CN115726763A - Ultrasonic imaging logging system and method for well wall stratum while drilling - Google Patents

Abstract

The invention discloses an ultrasonic imaging well logging system for well wall stratum while drilling, which comprises: the first ultrasonic device is embedded in the outer wall of the middle part of the drill collar and is used for transmitting first ultrasonic pulse waves to a well wall interface and receiving pulse echoes reflected from the interface; the second type of ultrasonic device is provided with an upper transmitting array, a lower transmitting array and a receiving array positioned between the two transmitting arrays, transmits second type of ultrasonic pulse waves to a well wall stratum along opposite radial directions by the transmitting arrays, and receives ultrasonic pulse sliding wave trains which are transmitted through the stratum and refracted from drilling fluid in a well hole; and the acquisition and control processing device is used for carrying out receiving and transmitting control on the ultrasonic device when the drill collar rotates to a corresponding position, analyzing and processing the pulse echo and the ultrasonic pulse sliding wave train, and obtaining the propagation time and amplitude of the echo, and the longitudinal and transverse wave velocity and ultrasonic attenuation of the well wall stratum. The invention realizes the fine evaluation of the geometric shape of the borehole and the heterogeneity and the anisotropy of the stratum around the borehole wall under the well logging while drilling.

Description

Ultrasonic imaging well logging system and method for well wall stratum while drilling

Technical Field

The invention relates to the technical field of petroleum exploration and development, in particular to an ultrasonic imaging logging system and method for a well wall stratum while drilling.

Background

Along with the great improvement of the level and precision of petroleum drilling and well logging, the strength and scale of exploration and development of complex oil and gas reservoirs and unconventional reservoirs are increased, and particularly, the occurrence of a large number of horizontal wells and highly-deviated wells leads to the strong heterogeneity and anisotropy of well wall strata. In addition, the abnormal stress distribution of the well wall can also induce the anisotropy of the stratum and seriously affect the safety of oil and gas production, so the heterogeneity and the anisotropy evaluation of the reservoir are the challenges which must be faced in the oil exploration and development.

In the existing acoustic logging technology, a cable orthogonal dipole acoustic logging instrument and a while-drilling eccentric sound source acoustic logging instrument are commonly used for evaluating the heterogeneity and the anisotropy of a reservoir. The basic features of these conventional logging tool configurations are: the transmitter to receiver measurement source spacing is greater than 6ft, the adjacent receiver measurement spacing is typically 6in, and the source operating frequency range is approximately from 500Hz to 20kHz. However, in the process of implementing the present invention, the present inventors found that: due to the large measurement distance and the low working frequency of a sound source, the conventional logging instrument still has the large limitations of low measurement resolution, poor imaging precision, weak fine layering capability and the like in the aspects of evaluating the heterogeneity and the anisotropy of a reservoir; in addition, particularly in a horizontal well with obvious layering, the anisotropic parameters of the reservoir measured by an instrument are often incorrect due to the large influence of the surrounding rock effect, so that great risks are brought to the stability evaluation of the well wall and the hydraulic fracturing construction operation. Therefore, compared with an orthogonal dipole sound source and an eccentric sound source, the method can be used for evaluating the heterogeneity and the anisotropy of the reservoir in the ultrasonic frequency range of 100-300 kHz, and can be used for remarkably improving the measurement resolution and the imaging precision.

No matter the cable logging or the logging while drilling, the existing ultrasonic imaging logging technology is an imaging logging technology for acquiring a borehole wall medium image based on an ultrasonic pulse reflection echo method and dynamic rotary scanning, is used for evaluating the geometrical shape of a borehole and identifying cracks and holes of the borehole wall, and has very important significance for the evaluation of drilling engineering and oil and gas reservoirs. In the prior art, the ultrasonic imaging logging technology represents the circumferential change of the acoustic impedance of the stratum around the well wall by an echo amplitude imaging graph with high resolution. However, the inversion of the acoustic impedance of the borehole wall and the formation is simultaneously influenced by various factors such as drilling fluid media, formation wave velocity, density, incident angle and the like, so that the existing ultrasonic imaging logging technology cannot accurately measure the acoustic impedance and the wave velocity of the formation around the borehole wall, and the heterogeneity and the anisotropy of a reservoir layer cannot be evaluated.

Therefore, how to evaluate the reservoir heterogeneity and anisotropy with high resolution and high precision in the ultrasonic frequency band becomes a problem to be solved urgently.

Disclosure of Invention

In order to solve the technical problem, the invention provides an ultrasonic imaging logging system for a borehole wall formation while drilling, which comprises: the first ultrasonic device is embedded in the outer wall of the middle part of the drill collar and used for transmitting first ultrasonic pulse waves to a well wall interface and receiving pulse echoes reflected from the interface; the second type of ultrasonic device comprises an upper transmitting array and a lower transmitting array which are respectively embedded in the outer walls of the upper half part and the lower half part of the drill collar, and a receiving array which is embedded in the outer wall of the middle part of the drill collar, and is used for transmitting a second type of ultrasonic pulse wave to the well wall stratum along opposite radial directions respectively by each group of transmitting arrays, and receiving an ultrasonic pulse sliding wave train which is transmitted through the stratum and refracted from drilling fluid in a well hole by the receiving array; and the acquisition and control processing device is used for carrying out transceiving control on the first type of ultrasonic device and the second type of ultrasonic device when the drill collar rotates to a corresponding position, and analyzing and processing the pulse echo and the ultrasonic pulse sliding wave train to obtain echo propagation time and amplitude, and longitudinal and transverse wave speed and ultrasonic attenuation data of a well wall stratum.

Preferably, the first type of ultrasonic device comprises a plurality of ultrasonic sensors integrated with each other, and the ultrasonic sensors integrated with each other are installed at the same depth position, wherein the ultrasonic sensors integrated with each other are distributed at intervals of 90 ° along the circumferential direction.

Preferably, the upper transmitting array comprises a first transmitting ultrasonic sensor and a second transmitting ultrasonic sensor, and the first transmitting ultrasonic sensor and the second transmitting ultrasonic sensor are installed at the same depth position and distributed at intervals of 180 degrees along the circumferential direction; the lower transmitting array comprises a third transmitting ultrasonic sensor and a fourth transmitting ultrasonic sensor, the third transmitting ultrasonic sensor and the fourth transmitting ultrasonic sensor are arranged at the same depth position and distributed at intervals of 180 degrees along the circumferential direction, and the radial direction corresponding to the first transmitting ultrasonic sensor is the same as the radial direction corresponding to the third transmitting ultrasonic sensor.

Preferably, the receiving array comprises a plurality of groups of receiving stations distributed at intervals along the axial direction of the borehole wall, each group of receiving stations comprises a first receiving ultrasonic sensor and a second receiving ultrasonic sensor, the first receiving ultrasonic sensor and the second receiving ultrasonic sensor are installed at the same depth position and distributed at intervals of 180 degrees along the circumferential direction, the radial directions corresponding to all the first receiving ultrasonic sensors are the same, and the radial directions corresponding to the first receiving ultrasonic sensors are the same as the radial directions corresponding to the first transmitting ultrasonic sensors.

Preferably, the acquisition and control processing device comprises: the receiving and transmitting integrated control circuit is used for synchronously exciting all the receiving and transmitting integrated ultrasonic sensors to transmit the first type of ultrasonic pulse waves and parallelly receiving the pulse echoes detected by all the sensors under the control of a first transmitting instruction; the transmitting circuit is used for exciting the sensors in the upper transmitting array and the lower transmitting array to synchronously transmit the second type of ultrasonic pulse waves under the control of a second transmitting instruction; the receiving circuit is used for receiving the ultrasonic pulse sliding wave train including sliding longitudinal waves, transverse waves and pseudo-Rayleigh waves detected by each sensor in the receiving array in parallel; the acquisition module is used for acquiring the pulse echo or the ultrasonic pulse sliding wave train received by each channel in parallel; and the main control module is used for sequentially sending the first transmitting instruction and the second transmitting instruction to the receiving-transmitting integrated control circuit and the transmitting circuit in a time-sharing manner when the drill collar rotates to a corresponding azimuth angle so as to receive the pulse echo and the ultrasonic pulse sliding wave train acquired under the corresponding azimuth angle and perform analysis processing.

Preferably, the acquisition and control processing device further comprises: and the azimuth detection circuit is used for acquiring various logging tool face angle information, and extracting an azimuth measurement value corresponding to the current measurement point based on the information so as to transmit the azimuth measurement value to the main control module.

Preferably, the acquisition and control processing device comprises: and the data reading circuit is connected with a ground device and used for reading the obtained analysis processing result in real time and transmitting the reading result to the ground device, wherein the ground device is used for calculating the geometrical shape of the borehole according to the obtained echo propagation time information of the omnibearing angle under different logging depths, evaluating the acoustic impedance characteristic of a borehole wall medium according to the obtained echo amplitude information of the omnibearing angle under different logging depths, thus obtaining a first type of circumferential imaging graph of the reflection characteristic of the borehole wall medium according to the analysis result of the geometrical shape of the borehole and the acoustic impedance characteristic of the borehole wall medium, and obtaining a second type of circumferential imaging graph representing the wave velocity and attenuation of the borehole wall stratum according to the obtained longitudinal and transverse wave velocity and ultrasonic attenuation characteristics of the borehole wall stratum under different logging depths and thus determining the circumferential change of the wave velocity of the stratum and evaluating and analyzing the anisotropy of the stratum around the borehole wall.

Preferably, the acquisition and control processing device is installed on the inner wall of a drill collar through a square prism framework and filled with high-temperature-resistant silica gel, wherein the drill collar is a non-magnetic drill collar which is arranged in a drilling fluid medium in a well hole and is connected with the underground drilling tool through a screw thread.

In another aspect, the present invention further provides an ultrasonic imaging logging method for a borehole wall formation while drilling, the method being implemented by using the ultrasonic imaging logging system as described above, the ultrasonic imaging logging method including: transmitting a first type of ultrasonic pulse wave to a well wall interface at the current drill collar rotation position, and receiving a pulse echo reflected from the interface; transmitting a second type of ultrasonic pulse wave to the well wall stratum by each group of transmitting arrays in the current position along opposite radial directions respectively, and receiving an ultrasonic pulse sliding wave train which is transmitted through the stratum and refracted from drilling fluid in a well hole by the receiving array; and analyzing and processing the acquired pulse echo and the ultrasonic pulse sliding wave train to respectively obtain the propagation time and amplitude of the echo, and the wave velocity of longitudinal waves and the wave velocity of ultrasonic waves of the well wall stratum and ultrasonic attenuation data.

Preferably, the analysis processing result obtained under the corresponding rotation direction is read in real time, and the read result is transmitted to the ground device; calculating the geometrical shape of the borehole according to the acquired echo propagation time information of the omnibearing angle under different logging depths, and evaluating the acoustic impedance characteristic of the borehole wall medium according to the acquired echo amplitude information of the omnibearing angle under different logging depths, so as to obtain a first-class circumferential imaging graph of the reflection characteristic of the borehole wall medium according to the analysis result of the geometrical shape of the borehole and the acoustic impedance characteristic of the borehole wall medium; and according to the acquired longitudinal and transverse wave velocities and ultrasonic attenuation characteristics of the borehole wall stratum at all angles under different logging depths, acquiring a second type of circumferential imaging graph representing the wave velocity and attenuation of the borehole wall stratum so as to determine the circumferential change of the stratum wave velocity, and evaluating and analyzing the anisotropy and anisotropy of the stratum around the borehole wall.

Compared with the prior art, one or more embodiments in the above scheme can have the following advantages or beneficial effects:

the invention discloses an ultrasonic imaging logging system and method for a well wall stratum while drilling. The system and the method are used for solving the technical problems of low measurement resolution, poor imaging precision, large influence of surrounding rock effect, weak fine layering capacity and the like in the prior art, and the characteristics of the wave velocity of the stratum around the well wall, the shape of the well bore, the acoustic impedance of a well wall medium and the like are subjected to circumferential scanning imaging by adopting an ultrasonic pulse transceiving and ultrasonic pulse echo combined measurement technology, so that a high-resolution and high-definition circumferential imaging graph of the wave velocity of the well wall and a circumferential imaging graph of well wall medium reflection can be obtained in the logging-while-drilling process, the geometric shape of the well bore and the heterogeneity and anisotropy of complex oil and gas reservoirs and unconventional oil and gas reservoirs of the stratum around the well wall are finely evaluated, the geological guiding operation is facilitated, the change of the lithology, the structural characteristics and the dip angle of the stratum is evaluated, and the application range of the ultrasonic imaging logging technology is greatly expanded.

In addition, the method can effectively obtain the well wall stratum wave velocity circumferential imaging graph and the well wall medium reflection circumferential imaging graph simultaneously in one-time logging while drilling process, reduces the influence of drilling fluid invasion, ensures that the measurement result can more truly reflect the characteristics of the original stratum, and has the advantages of high measurement resolution, excellent imaging precision, strong fine layering capability, high execution efficiency, more reliable measurement result and the like. The ultrasonic imaging well logging device and method for well wall stratum while drilling provided by the invention can evaluate the heterogeneity and anisotropy of the stratum around the well wall, evaluate the lithology, structural characteristics and change of stratum inclination angle of the stratum, and greatly expand the application range of the ultrasonic imaging well logging technology.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic diagram of the overall structure of an ultrasonic imaging logging system for a borehole wall formation while drilling according to an embodiment of the present application.

Fig. 2 is a schematic diagram of a specific structure and an application scenario of the ultrasonic imaging logging system for a borehole wall formation while drilling according to the embodiment of the present application.

FIG. 3 is a schematic diagram illustrating the operation of a first type of ultrasonic device in an ultrasonic imaging logging system for well wall formations while drilling according to an embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating an operation principle of a second type of ultrasonic device in the ultrasonic imaging logging system for well wall formation while drilling according to the embodiment of the application.

Fig. 5 is a schematic diagram of an internal structure of an acquisition and control processing device in an ultrasonic imaging logging system for a borehole wall formation while drilling according to an embodiment of the present application.

FIG. 6 is a flowchart illustrating operation of the ultrasonic imaging logging system for a borehole wall formation while drilling according to an embodiment of the present application.

FIG. 7 is a block diagram of a method of ultrasonic imaging logging while drilling a borehole wall formation according to an embodiment of the present application.

Detailed Description

The following detailed description of the embodiments of the present invention will be provided with reference to the drawings and examples, so that how to apply the technical means to solve the technical problems and achieve the technical effects can be fully understood and implemented. It should be noted that, as long as there is no conflict, the embodiments and the features of the embodiments of the present invention may be combined with each other, and the technical solutions formed are within the scope of the present invention.

Additionally, the steps illustrated in the flow charts of the figures may be performed in a computer system such as a set of computer-executable instructions. Also, while a logical order is shown in the flow diagrams, in some cases, the steps shown or described may be performed in an order different than here.

Along with the great improvement of the petroleum drilling and well logging level and precision, the strength and scale of exploration and development of complex oil and gas reservoirs and unconventional reservoirs are increased, and particularly, the well wall stratum presents strong heterogeneity and anisotropy when a large number of horizontal wells and highly deviated wells appear. In addition, the abnormal stress distribution of the well wall can also induce formation anisotropy, and seriously affect the safety of oil and gas production, so the heterogeneity and anisotropy evaluation of the reservoir become the challenges which must be faced in the oil exploration and development.

In the existing acoustic logging technology, a cable orthogonal dipole acoustic logging instrument and a while-drilling eccentric sound source acoustic logging instrument are commonly used for evaluating the heterogeneity and the anisotropy of a reservoir. The basic features of these conventional logging tool configurations are: the transmitter to receiver measurement source spacing is greater than 6ft, the adjacent receiver measurement spacing is typically 6in, and the source operating frequency range is approximately from 500Hz to 20kHz. However, in the process of implementing the present invention, the present inventors found that: due to the large measurement distance and the low working frequency of a sound source, the conventional logging instrument still has the large limitations of low measurement resolution, poor imaging precision, weak fine layering capability and the like in the aspects of evaluating the heterogeneity and the anisotropy of a reservoir; in addition, particularly in a horizontal well with obvious layering, the anisotropic parameters of the reservoir measured by an instrument are often incorrect due to the large influence of the surrounding rock effect, so that great risks are brought to the stability evaluation of the well wall and the hydraulic fracturing construction operation. Therefore, compared with an orthogonal dipole sound source and an eccentric sound source, the reservoir heterogeneity and anisotropy evaluation is carried out within the ultrasonic frequency range of 100-300 kHz, and the measurement resolution and the imaging precision can be remarkably improved.

No matter the cable logging or the logging while drilling, the existing ultrasonic imaging logging technology is an imaging logging technology for acquiring a borehole wall medium image based on an ultrasonic pulse reflection echo method and dynamic rotation scanning, is used for evaluating the geometrical shape of a borehole and identifying cracks and holes of the borehole wall, and has very important significance for drilling engineering and oil and gas reservoir evaluation. In the prior art, the ultrasonic imaging logging technology represents the circumferential change of the acoustic impedance of the stratum around the well wall by an echo amplitude imaging graph with high resolution. However, the inversion of the acoustic impedance of the borehole wall and the formation is simultaneously influenced by various factors such as drilling fluid media, formation wave velocity, density, incident angle and the like, so that the existing ultrasonic imaging logging technology cannot accurately measure the acoustic impedance and the wave velocity of the formation around the borehole wall, and the heterogeneity and the anisotropy of a reservoir layer cannot be evaluated.

Therefore, how to evaluate the reservoir heterogeneity and anisotropy with high resolution and high precision in the ultrasonic frequency band becomes a problem to be solved urgently.

Accordingly, in order to solve one or more of the above technical problems, the present invention provides an ultrasonic imaging logging system and method for a borehole wall formation while drilling. The system and the method take the drill collar as a bearing frame and mainly comprise the following steps: the system comprises a first type ultrasonic device which is formed into a self-sending and self-receiving ultrasonic well logging acoustic system, a second type ultrasonic device which is formed into a double-sending and four-receiving ultrasonic well logging acoustic system, and an acquisition and control processing device which is connected with the two types of ultrasonic devices. The first-class ultrasonic device can transmit ultrasonic pulse waves and receive reflected pulse echoes from a well wall interface through a four-array-element ultrasonic probe array; the second type of ultrasonic device can transmit ultrasonic pulse waves and receive ultrasonic pulse sliding wave trains which are transmitted through a well wall stratum and refracted from drilling fluid in a well through a double-transmitting four-receiving ultrasonic logging acoustic system; and then, the acquisition and control processing device can acquire the reflected pulse echo and the refracted ultrasonic pulse sliding wave train, acquire a borehole wall medium reflection circumferential imaging graph containing echo propagation time and amplitude characteristic information by analyzing and processing the reflected pulse echo, and acquire a borehole wall circumferential imaging graph containing longitudinal and transverse wave velocity and ultrasonic attenuation characteristic information of the stratum by analyzing and processing the ultrasonic pulse sliding wave train.

Therefore, the invention can carry out circumferential scanning imaging on the characteristics of the wave velocity of the stratum around the well wall, the shape of the well bore, the acoustic impedance of the medium of the well wall and the like, thereby obtaining a high-resolution and high-definition circumferential imaging graph of the wave velocity of the stratum of the well wall and a circumferential imaging graph of the reflection of the medium of the well wall in the logging-while-drilling process, and being used for finely evaluating the geometric shape of the well bore and the heterogeneity and the anisotropy of the stratum around the well wall, thereby realizing the fine evaluation of the geometric shape of the well bore and the heterogeneity and the anisotropy of the stratum around the well wall under the logging-while-drilling condition.

It should be noted that "up" and "down" as used in the embodiments of the present invention refer to relative positions with respect to the axial direction of the drill collar. Further, in embodiments of the present invention, "up" and "down" characterize locations closer to the wellhead and closer to the bottom of the well, respectively.

FIG. 1 is a schematic diagram of the overall structure of an ultrasonic imaging logging system for a borehole wall formation while drilling according to an embodiment of the present application. As shown in fig. 1, the ultrasonic imaging logging system of the present invention includes: a first type ultrasonic device A, a second type ultrasonic device B and an acquisition and control processing device C.

Fig. 2 is a schematic diagram of a specific structure and an application scenario of the ultrasonic imaging logging system for a borehole wall formation while drilling according to the embodiment of the present application. As shown in FIG. 2, a first type of ultrasonic device A is embedded in the outer wall of the middle part of the drill collar. The second type of ultrasound device B includes an upper transmit array 31, a lower transmit array 32, and a receive array 4. The upper transmitting array 31 is embedded in the outer wall of the upper half part of the drill collar, the lower transmitting array 32 is embedded in the outer wall of the lower half part of the drill collar, and the receiving array 4 is located between the upper transmitting array 31 and the lower transmitting array 32. Further, a first distance formed by the geometric center position of the upper transmitting array 31 and the geometric center position of the receiving array 4 is equal to a second distance formed by the geometric center position of the lower transmitting array 32 and the geometric center position of the receiving array 4. That is, the upper and lower transmission arrays 31 and 32 are symmetric with respect to the reception array 4.

In particular, with reference to fig. 1, acquisition and control processing means C are connected to first type ultrasound means a and second type ultrasound means B. The acquisition and control processing device C is used for carrying out ultrasonic receiving and transmitting control on the first type of ultrasonic device A and the second type of ultrasonic device B when the drill collar rotates to a corresponding position, analyzing and processing pulse echoes acquired from the first type of ultrasonic device A and ultrasonic pulse sliding wave trains acquired from the second type of ultrasonic device B, and respectively obtaining echo propagation time and amplitude, and longitudinal and transverse wave velocity and ultrasonic attenuation data of a well wall stratum. The first type of ultrasonic device A is used for transmitting a first type of ultrasonic pulse wave to a borehole wall interface 61 formed by a drilling fluid medium 62 in a borehole and a borehole wall stratum 6 and receiving a pulse echo reflected from the interface when the drill collar rotates to a corresponding position. The second type ultrasonic device B is used for enabling each group of the transmitting arrays 31 and 32 to respectively transmit second type ultrasonic pulse waves to the borehole wall stratum along opposite radial directions when the drill collar rotates to a corresponding position, and the receiving array 4 receives ultrasonic pulse sliding wave trains which are transmitted through the stratum and refracted back from drilling fluid in the borehole.

In the embodiment of the invention, the acquisition and control processing device C is mounted on the inner wall of the drill collar through a square prism framework 50. Specifically, the acquisition and control processing device C is integrated in the electronic cabin 5, wherein the electronic cabin 5 is nested and sealed on the inner wall (or inside) of the drill collar 1, and is filled with high temperature resistant silica gel for vibration reduction and heat dissipation. Further, the drill collar 1 is a non-magnetic drill collar, the non-magnetic drill collar 1 is arranged in a drilling fluid medium in a well hole, and the non-magnetic drill collar 1 is connected with the underground drilling tool assembly through threads. More specifically, the non-magnetic drill collar 1 is cast from steel alloy material and is constructed as a non-magnetic mounting bearing frame which is placed in the drilling fluid medium in the borehole, and the outer wall of the drill collar and the borehole wall interface form an external drilling fluid environment. The non-magnetic drill collar 1 is internally provided with a water hole 11 for realizing the internal and external circulation of drilling fluid. The upper end and the lower end of the non-magnetic drill collar 1 are provided with standard NC50 male and female screw threads 12 and 13 which are used for being screwed in a down-hole drilling tool assembly.

Thus, with the increase of the logging depth and the continuous rotation of the drilling tool along the circumferential direction, the ultrasonic imaging logging system according to the embodiment of the present invention can trigger the ultrasonic transceiver mechanisms of the first type ultrasonic device a and the second type ultrasonic device B through the device C in the corresponding directions to obtain the reflected pulse echoes and the ultrasonic pulse sliding wave trains in the corresponding directions, so as to obtain the echo propagation time, the echo amplitude characteristics, the longitudinal and transverse wave velocities of the borehole wall formation and the ultrasonic attenuation characteristics of the borehole wall formation in the corresponding logging depth by analyzing and processing the reflected pulse echoes and the ultrasonic pulse sliding wave trains acquired in each direction of the corresponding logging depth through the acquisition and control processing device C, and further analyze the formation velocity, the borehole geometric shape and the borehole wall medium around the borehole wall by using the information (the echo propagation time information and the echo amplitude information of the omnidirectional angles at different logging depths, and the longitudinal and transverse wave velocity and the ultrasonic attenuation characteristics of the borehole wall at the omnidirectional angles at different logging depths) to evaluate and analyze the anisotropy of the formation around the borehole.

FIG. 3 is a schematic diagram illustrating the operation of a first type of ultrasonic device in an ultrasonic imaging logging system for well wall formations while drilling according to an embodiment of the present invention. FIG. 4 is a schematic diagram illustrating the operation principle of a second type of ultrasonic device in an ultrasonic imaging logging system for a borehole wall formation while drilling according to an embodiment of the present application. The detailed structure and function of the ultrasonic imaging logging system according to the embodiment of the present invention will be described in detail with reference to fig. 3 and 4.

The side wall of the non-magnetic drill collar 1 is also provided with a plurality of groups of circumferential grooves for accommodating all array type ultrasonic well logging acoustic systems. In the embodiment of the invention, the array type ultrasonic well logging acoustic system works in the ultrasonic frequency range of 100-400 kHz and comprises a self-transmitting and self-receiving ultrasonic well logging acoustic system 2 and a double-transmitting and multi-receiving ultrasonic well logging acoustic system.

As shown in FIG. 3, the first type of ultrasonic device A according to the embodiment of the present invention is configured as a spontaneous and spontaneous ultrasound logging acoustic system 2. The first type of ultrasonic device A comprises a plurality of transmitting and receiving integrated ultrasonic sensors. All the transmitting and receiving integrated ultrasonic sensors are arranged at the same depth position. Wherein, each receiving and transmitting integrated ultrasonic sensor is distributed along the circumferential direction of the drill collar 1 at intervals of a preset angle.

In one embodiment, the spontaneous and spontaneous ultrasound logging acoustic system 2 according to the embodiment of the present invention is a four-array element ultrasound probe array. The four-array-element ultrasonic probe array is embedded in the outer wall of the non-magnetic drill collar 1 and comprises 4 receiving and transmitting integrated ultrasonic sensors which are positioned at the same depth and are arranged in a circumferential orthogonal 90-degree mode. The four-element ultrasonic probe array is used for transmitting first ultrasonic pulse waves to a drilling fluid medium 62 in a borehole and receiving pulse echoes reflected from a borehole wall interface 61.

Further, as shown in fig. 3, the four-element ultrasonic probe array 2 is composed of four ultrasonic sensors arranged orthogonally and integrated with each other. The four-array-element ultrasonic probe array 2 takes a groove in the side wall of the drill collar 1 as a bearing frame, and four receiving and transmitting integrated ultrasonic sensors are arranged in the groove with the same depth at intervals 90 along the circumferential direction of the outer wall of the drill collar.

Further, with reference to fig. 3, in the counterclockwise direction, the numbers of the four ultrasound sensors integrated with transceiver are TRE1, TRE2, TRE3, and TRE4, respectively. The receiving and transmitting integrated ultrasonic sensor adopts a broadband ultrasonic piezoelectric transducer, is of a cylindrical structure, and can transmit ultrasonic signals and receive the ultrasonic signals. As the array elements are all ultrasonic sensors integrating receiving and transmitting, the four-array-element ultrasonic probe array 2 forms a self-transmitting and self-receiving ultrasonic well logging acoustic system. In addition, the four-array element ultrasonic probe array 2 works in a self-transmitting and self-receiving mode, when the four-array element ultrasonic probe array is positioned in a drilling fluid medium 62 in a borehole, ultrasonic pulse waves can be simultaneously transmitted to 4 orthogonal directions, and pulse echoes reflected from a borehole wall interface 61 in the same direction as the transmitting direction are received. Therefore, the back-end equipment can estimate the geometrical shape of the borehole according to the propagation time of the pulse echo and evaluate the acoustic impedance characteristic of the borehole wall medium according to the amplitude of the pulse echo. In addition, in the embodiment of the invention, the center working frequency of the four-array element ultrasonic probe array 2 is near 250kHz, and the bandwidth is 200-280 kHz.

As shown in fig. 4, the second type of ultrasonic apparatus B according to the embodiment of the present invention is configured as a dual-transmitter multi-receiver ultrasonic logging acoustic system. The second type of ultrasonic device B is composed of an upper ultrasonic transmitter array 31, a lower ultrasonic transmitter array 32, and an ultrasonic receiver array 4. The upper and lower ultrasonic transmitter arrays 31, 32 each comprise a plurality of transmitting ultrasonic sensors, which may be distributed at circumferentially spaced preset angles. In addition, the embodiment of the present invention may also include a plurality of sets of upper ultrasonic emitter arrays 31, each set of upper ultrasonic emitter arrays 31 being distributed at a predetermined distance along the axial direction, and a plurality of sets of lower ultrasonic emitter arrays 32, each set of lower ultrasonic emitter arrays 32 being also distributed at a predetermined distance along the axial direction.

The receiving array 4 comprises a plurality of groups of receiving stations which are distributed at intervals along the axial direction of the well wall. Wherein each set of receiving stations further comprises a plurality of receiving ultrasonic sensors. The plurality of receiving ultrasonic sensors are distributed at preset angle intervals along the circumferential direction. The receiving ultrasonic sensors in each group of receiving stations are the same in number, and all the receiving ultrasonic sensors in different groups of receiving stations completely align the receiving ultrasonic sensors along the axial direction, so that the radial directions of all the receiving ultrasonic sensors in each group of receiving stations are the same.

In an embodiment, the dual-transmission multi-reception ultrasonic logging acoustic system according to the embodiment of the present invention is a dual-transmission four-reception ultrasonic logging acoustic system. The upper transmit array 31 includes a first transmit ultrasonic sensor and a second transmit ultrasonic sensor, and the lower transmit array 32 includes a third transmit ultrasonic sensor and a fourth transmit ultrasonic sensor. The first transmitting ultrasonic sensor and the second transmitting ultrasonic sensor are arranged at the same depth position and are distributed at intervals of 180 degrees along the circumferential direction; the third transmitting ultrasonic sensor and the fourth transmitting ultrasonic sensor are arranged at the same depth position and are distributed at intervals of 180 degrees along the circumferential direction. Further, the radial direction corresponding to the first transmitting ultrasonic sensor is the same as the radial direction corresponding to the third transmitting ultrasonic sensor; meanwhile, the radial direction corresponding to the second transmitting ultrasonic sensor is the same as the radial direction corresponding to the fourth transmitting ultrasonic sensor.

In addition, the receiving array 4 includes four sets of receiving stations. And each group of receiving stations are distributed along the axial direction of the drill collar at intervals according to the preset receiving stations. Each set of receiving stations includes a first receiving ultrasonic sensor and a second receiving ultrasonic sensor. The first receiving ultrasonic sensor and the second receiving ultrasonic sensor are arranged at the same depth position and are distributed at an interval of 180 degrees along the circumferential direction. And the radial directions corresponding to all the first receiving ultrasonic sensors are the same. Further, the radial direction corresponding to the first receiving ultrasonic sensor is the same as the radial direction corresponding to the first transmitting ultrasonic sensor; meanwhile, the radial direction corresponding to the second receiving ultrasonic sensor is the same as the radial direction corresponding to the second transmitting ultrasonic sensor.

Further, as shown in fig. 4, the upper ultrasonic transmitter array 31 is embedded in the outer wall of the non-magnetic drill collar and includes 2 transmitting ultrasonic sensors located on the upper portion of the non-magnetic drill collar 1 and arranged at 180 ° intervals in the circumferential direction. The upper ultrasonic transmitter array 31 is adapted to transmit a second type of ultrasonic pulse in the borehole drilling fluid medium 62 in radially opposite directions toward the borehole wall formation 6. The lower ultrasonic transmitter array 32 is embedded in the outer wall of the non-magnetic drill collar and comprises 2 transmitting ultrasonic sensors which are positioned at the lower part of the non-magnetic drill collar 1 and are arranged at intervals of 180 degrees in the circumferential direction. The lower ultrasonic transmitter array 32 is adapted to transmit a second type of ultrasonic pulse in a borehole drilling fluid medium 62 in radially opposite directions toward the borehole wall formation 6. The transmitting ultrasonic transducer included in the lower ultrasonic emitter array and the transmitting ultrasonic transducer included in the upper ultrasonic emitter array are high-power ultrasonic piezoelectric transducers with good working performance consistency. The ultrasonic receiver array 4 is embedded in the outer wall of the non-magnetic drill collar 1, is positioned in the middle of the upper ultrasonic transmitter array 31 and the lower ultrasonic transmitter array 32, and comprises 4 receiving stations which are axially arranged at equal intervals. Wherein each receiving station comprises 2 receiving ultrasonic sensors which are arranged at the same depth and are circumferentially spaced by 180 degrees. The ultrasonic receiver array 4 is used for receiving ultrasonic pulse sliding wave trains propagated in the stratum 6 around the well wall, and longitudinal and transverse wave speeds of the well wall stratum on the side of the ultrasonic receiver array 4 can be obtained in subsequent equipment according to the similarity correlation of array waveforms.

Further, with continued reference to FIG. 4, the dual-transmitter-four-receiver ultrasonic logging system uses a groove on the sidewall of the drill collar 1 as a carrier, wherein the upper ultrasonic transmitter array 31 is disposed on the upper portion of the drill collar 1, the lower ultrasonic transmitter array 32 is disposed on the lower portion of the drill collar 1, and the ultrasonic receiver array 4 is disposed on the middle portion of the drill collar 1. As shown in FIG. 4, the upper ultrasonic transmitter array 31 comprises 2 transmitting ultrasonic sensors TANU and TAPU, which are embedded in the upper 2 grooves arranged at the same depth on the side wall of the drill collar 1 at 180 DEG intervals in the circumferential direction. Similarly, the lower ultrasonic transmitter array 32 comprises 2 transmitting ultrasonic sensors TAND and TAPD embedded in the lower 2 grooves circumferentially spaced 180 ° apart at the same depth in the sidewall of the drill collar 1. The transmitting ultrasonic sensor of the upper ultrasonic transmitter array 31 and the transmitting ultrasonic sensor of the lower ultrasonic transmitter array 32 are high-power ultrasonic columnar piezoelectric transducers with good working performance consistency, and can transmit ultrasonic pulse waves outwards under the action of high-voltage excitation pulses, and the main frequency of the pulse waves is near 230 kHz.

With continued reference to fig. 4, the ultrasonic receiver array 4 contains 4 receiving stations, each of which in turn contains 2 receiving ultrasonic sensors, for a total of 8 receiving ultrasonic sensors. The 8 receiving ultrasonic sensors can be divided into 2 groups of four-element ultrasonic receiver arrays 41 and 42. The four-array element ultrasonic receiver array 41 is embedded in 4 grooves which are axially arranged on the side wall of the drill collar 1 at equal intervals, and similarly, the four-array element ultrasonic receiver array 42 is also embedded in 4 grooves which are axially arranged on the side wall of the drill collar 1 at equal intervals in the 180-degree direction opposite to the groove. In the ultrasonic receiver array 4, 8 receiving ultrasonic sensors are all broadband high-sensitivity ultrasonic composite piezoelectric transducers with good consistency, and can receive ultrasonic pulse waves in the ultrasonic frequency range of 100-400 kHz.

Therefore, the borehole wall formation ultrasonic imaging logging while drilling system according to the embodiment of the invention can construct two dual-transmitting four-receiving ultrasonic logging acoustic systems, wherein the transmitting ultrasonic sensor TAPU in the upper ultrasonic transmitter array 31, the transmitting ultrasonic sensor TAPD in the lower ultrasonic transmitter array 32 and the four-array element ultrasonic receiver array 41 form one dual-transmitting four-receiving ultrasonic logging acoustic system; the transmitting ultrasonic sensor TANU in the ultrasonic transmitter array 31, the transmitting ultrasonic sensor TAND in the lower ultrasonic transmitter array 32 and the four-element ultrasonic receiver array 42 in the 180-degree direction opposite to the same constitute another dual-transmitting four-receiving ultrasonic logging acoustic system. Meanwhile, the dual-transmitting four-receiving ultrasonic well logging acoustic system can transmit ultrasonic pulse waves to the well wall stratum 6in two opposite directions in the medium of the well drilling fluid 62, the ultrasonic pulse waves are transmitted in the well wall stratum 6 and are refracted back to the well drilling fluid continuously to be received by the dual-transmitting four-receiving ultrasonic well logging acoustic system, and the received ultrasonic pulse sliding wave train comprises stratum longitudinal waves, transverse waves and pseudo-Rayleigh waves. Finally, the longitudinal and transverse wave velocity and the ultrasonic attenuation of the formation around the borehole wall in two opposite directions can be obtained according to the similarity correlation of the array waveforms, and the dual-transmitting four-receiving ultrasonic well logging acoustic system has borehole compensation effect in the region with severe borehole change due to the fact that the ultrasonic receiver array 4 is located between the upper ultrasonic transmitter array 31 and the lower ultrasonic transmitter array 32. In the logging-while-drilling process, the upper ultrasonic transmitter array, the lower ultrasonic transmitter array and the ultrasonic receiver array rotate along with the rotation of the drill collar, so that ultrasonic pulse sliding wave trains of the well wall stratum in different circumferential directions can be received, and the stratum wave speed can be measured. According to all the measured formation wave velocities within the range of 360 degrees, a circumferential imaging graph of the well wall formation wave velocities can be obtained so as to determine the circumferential variation of the formation wave velocities, and the circumferential imaging graph is used for evaluating and analyzing the heterogeneity and the anisotropy of the formations around the well wall.

In addition, the measurement resolution, imaging precision, amplitude of ultrasonic pulse wave and the like of the double-transmitting and four-receiving ultrasonic logging acoustic system are related to the ultrasonic measurement frequency band and the measurement source distance and the distance. Compared with the conventional sonic logging, the measurement source distance and the distance of the dual-transmitting four-receiving ultrasonic logging acoustic system are greatly shortened, the measurement source distance range is 6-8.4 cm, and the measurement distance is 8-10 mm, so that the well wall and stratum ultrasonic imaging logging device while drilling disclosed by the embodiment of the invention has good measurement resolution and imaging precision, and the signal-to-noise ratio of ultrasonic pulse waves is considered at the same time.

Further, the acquisition and control processing device C is electrically connected with the four-array-element ultrasonic probe array 2, the upper ultrasonic transmitter array 31, the lower ultrasonic transmitter array 32 and the ultrasonic receiver array 4, and is used for acquiring a reflected pulse echo from the well wall interface and an ultrasonic pulse glide wave train propagating along the well wall stratum, analyzing and processing the reflected pulse echo and the ultrasonic pulse glide wave train, and thus acquiring the propagation time and amplitude of the ultrasonic pulse echo and the wave velocity and ultrasonic attenuation of the well wall stratum. Fig. 5 is a schematic diagram of an internal structure of an acquisition and control processing device in an ultrasonic imaging logging system for a borehole wall formation while drilling according to an embodiment of the present application. The structure and function of the acquisition and control processing device C according to the embodiment of the present invention will be described in detail with reference to fig. 5.

As shown in fig. 5, the acquisition and control processing device C includes: the device comprises a main control module 51, an acquisition module 52, a transmitting-receiving integrated control circuit 53, a transmitting circuit 54 and a receiving circuit 55.

The transceiver-integrated control circuit 53 is configured to synchronously excite (or simultaneously excite) all transceiver-integrated ultrasonic sensors to transmit the first type of ultrasonic pulse waves and to receive pulse echoes detected by the sensors in parallel under the control of the first transmission instruction. In the embodiment of the present invention, referring to fig. 5, the transceiver-integrated control circuit 53 is formed by four independent excitation and reception channels, and the four channels are electrically connected to each (transceiver-integrated ultrasonic) sensor array element in the four-array-element ultrasonic probe array 2, respectively. The integrated transceiver control circuit 53 can simultaneously excite the four integrated transceiver ultrasonic sensors by using the first transmission command to transmit the first type of ultrasonic pulse waves, and can receive four amplified and reflected pulse echoes in parallel.

The transmitting circuit 54 is used for exciting all the sensors in the upper transmitting array 31 and the lower transmitting array 32 to synchronously transmit the second type of ultrasonic pulse waves under the control of a second transmitting instruction. In an embodiment of the present invention, referring to fig. 5, the transmitting circuit 54 is formed by at least two excitation channels electrically connected to the upper and lower arrays of ultrasound transmitters 31 and 32, respectively. The transmitting circuit 54 can synchronously drive the upper ultrasonic transmitter array 31 and the lower ultrasonic transmitter array 32 to transmit the ultrasonic pulse waves of the second type outwards by using the second transmitting instruction.

The receiving circuit 55 is used for receiving the ultrasonic pulse sliding wave train including sliding longitudinal waves, transverse waves and pseudo-rayleigh waves detected by all the receiving ultrasonic sensors in the ultrasonic receiver array 4 in parallel. In an embodiment of the present invention, referring to fig. 5, the receiving circuit 55 is formed by at least eight receiving channels, and the eight receiving channels are electrically connected to the sensors in the ultrasonic receiver array 4 respectively. The receive circuitry 55 is capable of receiving eight amplified ultrasonic pulse glide trains in parallel that propagate through the borehole wall formation and are refracted from the drilling fluid in the borehole.

The acquisition module 52 is configured to acquire pulse echoes or ultrasonic pulse train received by each (receiving) channel in parallel. In the embodiment of the present invention, referring to fig. 5, the acquisition circuit 52 is composed of at least 12 independent parallel acquisition channels, and the 12 receiving channels are electrically connected to four receiving channels in the transceiver integrated control circuit 53 and eight receiving channels in the receiving circuit 55, respectively. The acquisition module 52 is capable of acquiring the ultrasound pulse echo and the ultrasound pulse glide wave train synchronously.

The main control module 51 is a control processor with a digital signal processor as a core, and is mainly responsible for controlling the downhole work flow and data processing work. Specifically, the main control module 51 is configured to sequentially send a first transmitting instruction and a second transmitting instruction to the transceiver integrated control circuit and the transmitting circuit in a time-sharing manner when the drill collar rotates to a corresponding azimuth angle, so as to sequentially drive the first type of ultrasonic device a to detect a pulse echo at the current azimuth angle, and the second type of ultrasonic device B to detect an ultrasonic pulse sliding wave train at the current azimuth angle, and then receive a plurality of paths (four paths) of pulse echoes and a plurality of paths (eight paths) of ultrasonic pulse sliding wave trains acquired at the corresponding azimuth angle, and analyze and process the plurality of paths of pulse echoes and the plurality of paths of ultrasonic pulse sliding wave trains acquired. During analysis, the main control module 51 is configured to obtain echo propagation time and echo amplitude characteristics (information) according to the collected multiple paths of pulse echoes at the current azimuth angle, and obtain longitudinal and transverse wave velocities of the borehole wall formation and ultrasonic attenuation characteristics (information) of the borehole wall formation by using an array waveform similarity correlation method according to the collected multiple paths of) ultrasonic pulse sliding wave trains at the current azimuth angle, so as to represent (collected information) analysis processing results corresponding to the current azimuth angle (measurement point) by using the echo propagation time, the echo amplitude characteristics, the longitudinal and transverse wave velocities of the borehole wall formation and the ultrasonic attenuation characteristics of the borehole wall formation.

In addition, in the embodiment of the present invention, the acquisition and control processing device C further includes an orientation detection circuit 57. The azimuth detection circuit 57 is connected to the main control module 51. The azimuth detection circuit 57 is configured to obtain face angle information of various logging tools, and based on the face angle information, extract an azimuth measurement value corresponding to a current measurement point (a measurement azimuth in a current logging depth) to transmit the azimuth measurement value to the main control module 51, so as to provide support for the main control module 51 for analysis results of pulse echoes and ultrasonic pulse sliding wave trains. Specifically, the azimuth detection circuit 57 is composed of an azimuth sensor and a detection circuit, and can acquire azimuth information of different types of tool surfaces, such as a gravity tool surface and a magnetic tool surface, so as to provide an azimuth measurement value corresponding to the current measurement point.

Further, in the embodiment of the present invention, the acquisition and control processing device C further includes a data reading circuit 58, a storage circuit 56, and a power supply circuit 59.

The memory circuit 56 is a large-capacity nonvolatile memory, and can realize functions such as memory management and data storage. In the embodiment of the present invention, the storage circuit 56 is configured to store waveform data of all measured points (i.e., a plurality of pulse echoes and a plurality of ultrasonic pulse gliding wave trains corresponding to each measured point) and analysis result data obtained by the main control module 51 for all measured points.

The power supply circuit 59 takes a DC/DC power supply module as a core, is connected with the high-temperature lithium battery pack, and is configured to generate at least five power supply voltages required by each internal circuit unit (for example, the main control module 51, the acquisition module 52, the transceiver integrated control circuit 53, the transmission circuit 54, the reception circuit 55, and the orientation detection circuit 57) through DC/DC conversion processing.

The data reading circuit 58 is connected to a ground device (not shown) and the main control module 51. The data reading circuit 58 is configured to read, in real time, analysis processing results of the multi-channel pulse echoes and the multi-channel ultrasonic pulse sliding wave trains corresponding to different measurement points, which are obtained from the main control module 51 (the analysis processing results including echo propagation time, echo amplitude characteristics, longitudinal and transverse wave speeds of the borehole wall formation, and borehole wall formation ultrasonic attenuation characteristic data are obtained for each measurement point), and transmit the read results to the ground device. In the embodiment of the present invention, the data reading circuit 58 is composed of a high-speed CAN bus, and is responsible for reading waveform data (a multi-channel pulse echo and a multi-channel ultrasonic pulse sliding wave train corresponding to each measurement point) and analysis result data stored in the instrument, and uploading the read information to the ground computer.

At the moment, the ground device is used for calculating the geometrical shape of the borehole according to the acquired echo propagation time information of the omnibearing angles under different logging depths, and evaluating the acoustic impedance characteristic of the borehole wall medium according to the acquired echo amplitude information of the omnibearing angles under different logging depths, so that a first type of circumferential imaging graph representing the reflection characteristic of the borehole wall medium is further acquired according to the analysis result of the geometrical shape of the borehole and the acoustic impedance characteristic of the borehole wall medium. In addition, the ground device is also used for obtaining a second type of circumferential imaging graph representing the wave velocity and the attenuation characteristic of the well wall stratum according to the obtained longitudinal and transverse wave velocity and the ultrasonic attenuation characteristic of the well wall stratum at all angles under different logging depths so as to determine the circumferential change of the wave velocity of the stratum, and therefore the anisotropy and the anisotropy of the stratum around the well wall are evaluated and analyzed by utilizing the circumferential change information of the wave velocity and the attenuation characteristic of the stratum.

Each circuit unit takes a square prism framework 50 (see fig. 1) as a bearing frame to form an ultrasonic acquisition control processing electronic bin 5. The ultrasonic acquisition control processing electronic bin 5 is nested and sealed on the inner wall of the drill collar 1, filled with high-temperature silica gel for vibration reduction and heat dissipation and used for acquiring, processing and analyzing reflected pulse echoes from a well wall interface and an ultrasonic pulse sliding wave train transmitted along a well wall stratum, so that the transmission time and amplitude of the ultrasonic pulse echoes and the longitudinal and transverse wave velocities and ultrasonic attenuation of the well wall stratum can be obtained.

FIG. 6 is a flow chart of the operation of an ultrasonic imaging logging system for drilling a borehole wall formation according to an embodiment of the present application. As shown in fig. 6, the ultrasonic imaging well logging system for borehole wall formation while drilling provided by the embodiment of the present invention can perform ultrasonic imaging well logging while drilling in a drilling process, and an ultrasonic reflection method and a refraction method are used to comprehensively evaluate the borehole geometry, and the heterogeneity and anisotropy of the borehole wall formation. As shown in fig. 6, the specific implementation flow includes the following steps:

step 71: at a certain time t1, the four-array-element ultrasonic probe array 2 simultaneously transmits first ultrasonic pulse waves to 4 orthogonal directions in a drilling fluid medium in a borehole in a self-transmitting and self-receiving mode, the first ultrasonic pulse waves encounter a borehole wall interface formed by the drilling fluid and a stratum to generate reflected pulse echoes, and at the moment, the reflected pulse echoes are reflected back along the same direction and are received by the four-array-element ultrasonic probe array 2.

Step 72: at the next moment t2 (t 2-t1>400 us), the dual-transmitting four-receiving ultrasonic well logging acoustic system works in a dual-transmitting four-receiving mode, namely the upper ultrasonic transmitter array 31 and the lower ultrasonic transmitter array 32 synchronously transmit second ultrasonic pulse waves to the well wall stratum in parallel in two opposite radial directions in a well drilling fluid medium, the ultrasonic pulse waves are transmitted in the well wall stratum and continuously refracted back to the well drilling fluid, and an ultrasonic pulse sliding wave train containing sliding longitudinal waves, transverse waves and pseudo-rayleigh waves is generated. The ultrasonic receiver array 4 receives ultrasonic pulse gliding wave trains which are propagated and refracted back from the stratum around the side borehole wall in the borehole drilling fluid medium.

Step 73: in the logging-while-drilling process, the steps 71 and 72 are alternately repeated along with the rotation of the drill collar, so that ultrasonic pulse echoes of different directions in the 360-degree range of the whole borehole and ultrasonic pulse sliding wave trains containing sliding longitudinal waves, transverse waves and pseudo-Rayleigh waves at different logging depths are recorded.

Step 74: the acquisition and control processing device in the electronic bin 5 records, analyzes and processes all pulse echoes and ultrasonic pulse sliding wave trains in a 360-degree range of the whole borehole; and then obtaining a borehole wall medium reflection circumferential imaging graph according to the arrival time and amplitude of the pulse echo obtained by analysis and processing, and obtaining a borehole wall stratum wave velocity and an attenuated circumferential imaging graph according to the longitudinal and transverse wave velocities and ultrasonic attenuation of the borehole wall stratum extracted by the analysis and processing in different circumferential directions.

Step 75: by comprehensively analyzing the borehole wall medium reflection circumferential imaging graph and the wave velocity and attenuation circumferential imaging graph of the borehole wall stratum, the geometric shape of the borehole and the heterogeneity and anisotropy of the stratum around the borehole wall can be evaluated finely.

On the other hand, based on the ultrasonic imaging well logging system, the embodiment of the invention also provides an ultrasonic imaging well logging method for the well wall stratum while drilling, and the method is realized through the ultrasonic imaging well logging system. FIG. 7 is a block diagram of a method of ultrasonic imaging logging while drilling a borehole wall formation according to an embodiment of the present application.

As shown in fig. 7, the ultrasonic imaging logging method according to the embodiment of the present invention includes the following steps: s101, transmitting a first type of ultrasonic pulse wave to a well wall interface at the current drill collar rotation position, and receiving a pulse echo reflected from the well wall interface; s102, transmitting a second type of ultrasonic pulse wave to the borehole wall stratum from each group of transmitting arrays in opposite radial directions at the current rotary position of the drill collar, and receiving an ultrasonic pulse sliding wave train which is transmitted through the stratum and refracted from drilling fluid in a borehole by the receiving array; step S103 analyzes and processes the pulse echo acquired in step S101 and the ultrasonic pulse gliding wave train acquired in step S102, and obtains echo propagation time and amplitude, and longitudinal and transverse wave velocities and ultrasonic attenuation data of the borehole wall formation, respectively. Thus, the embodiment of the invention continuously repeats the steps S101 to S103 for each logging measurement point to obtain the echo propagation time information of the omnidirectional angle at different logging depths, the echo amplitude information of the omnidirectional angle at different logging depths, and the longitudinal and transverse wave velocity and the ultrasonic attenuation characteristics of the borehole wall stratum at the omnidirectional angle at different logging depths.

In addition, the ultrasonic imaging logging method further comprises the following steps: reading an analysis processing result obtained under the corresponding rotation direction in real time, and transmitting the reading result to the ground device; calculating the geometrical shape of the borehole according to the acquired echo propagation time information of the omnibearing angle under different logging depths, and evaluating the acoustic impedance characteristic of the borehole wall medium according to the acquired echo amplitude information of the omnibearing angle under different logging depths, so as to obtain a first-class circumferential imaging graph of the reflection characteristic of the borehole wall medium according to the analysis result of the geometrical shape of the borehole and the acoustic impedance characteristic of the borehole wall medium; and according to the acquired longitudinal and transverse wave velocities and ultrasonic attenuation characteristics of the borehole wall stratum at all angles under different logging depths, acquiring a second type of circumferential imaging graph representing the wave velocity and attenuation of the borehole wall stratum so as to determine the circumferential change of the stratum wave velocity, and evaluating and analyzing the anisotropy and anisotropy of the stratum around the borehole wall.

The invention discloses an ultrasonic imaging logging system and method for a well wall stratum while drilling. The system and the method aim to solve the technical problems of low measurement resolution, poor imaging precision, large surrounding rock effect influence, weak fine layering capability and the like in the prior art, and adopt an ultrasonic pulse transceiving technology and an ultrasonic pulse echo combined measurement technology to carry out circumferential scanning imaging on characteristics such as the wave velocity of the stratum around the well wall, the shape of the well bore, the acoustic impedance of the well wall medium and the like, so that a high-resolution and high-definition circumferential imaging graph of the wave velocity of the well wall stratum and a circumferential imaging graph of the reflection of the well wall medium can be obtained in the logging-while-drilling process, the system and the method are used for finely evaluating the geometrical shape of the well bore, the complex oil and gas reservoirs around the well wall and the heterogeneity and anisotropy of unconventional oil and gas reservoirs, are favorable for guiding geological guiding operation, evaluating the change of the lithology, the structural characteristics and the inclination angle of the stratum, and greatly expand the application range of the ultrasonic imaging logging technology.

In addition, the method can effectively acquire the well wall stratum wave velocity circumferential imaging graph and the well wall medium reflection circumferential imaging graph simultaneously in one-time logging-while-drilling process, reduces the influence of drilling fluid invasion, ensures that the measurement result can truly reflect the characteristics of the original stratum, and has remarkable effects in the aspects of measurement resolution, imaging precision, fine layering capability, execution efficiency, measurement result reliability and the like. The ultrasonic imaging logging device and method for the well wall stratum while drilling provided by the invention can evaluate the heterogeneity and anisotropy of the stratum around the well wall, and evaluate the change of the lithology, structural characteristics and stratum inclination angle of the stratum, thereby greatly expanding the application range of the ultrasonic imaging logging technology.

The above description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

It is to be understood that the disclosed embodiments of the invention are not limited to the particular structures, process steps, or materials disclosed herein but are extended to equivalents thereof as would be understood by those ordinarily skilled in the relevant arts. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrase "one embodiment" or "an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment.

Although the embodiments of the present invention have been described above, the above description is only for the convenience of understanding the present invention, and is not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (10)

1. An ultrasonic imaging logging system for use in a borehole wall formation while drilling, comprising:

the first ultrasonic device is embedded in the outer wall of the middle part of the drill collar and used for transmitting first ultrasonic pulse waves to a well wall interface and receiving pulse echoes reflected from the interface;

the second type of ultrasonic device comprises an upper transmitting array and a lower transmitting array which are respectively embedded in the outer walls of the upper half part and the lower half part of the drill collar, and a receiving array which is embedded in the outer wall of the middle part of the drill collar, and is used for transmitting a second type of ultrasonic pulse wave to the well wall stratum along opposite radial directions respectively by each group of transmitting arrays, and receiving an ultrasonic pulse sliding wave train which is transmitted through the stratum and refracted from drilling fluid in a well hole by the receiving array;

and the acquisition and control processing device is used for carrying out transceiving control on the first type of ultrasonic device and the second type of ultrasonic device when the drill collar rotates to a corresponding position, and analyzing and processing the pulse echo and the ultrasonic pulse sliding wave train to obtain echo propagation time and amplitude, and longitudinal and transverse wave speed and ultrasonic attenuation data of a well wall stratum.

2. The ultrasonic imaging logging system of claim 1, wherein the first type of ultrasonic device comprises a plurality of all-in-one ultrasonic sensors, each of the all-in-one ultrasonic sensors being mounted at a same depth position, wherein the all-in-one ultrasonic sensors are distributed at intervals of 90 ° in the circumferential direction.

3. The ultrasonic imaging logging system of claim 2,

the upper transmitting array comprises a first transmitting ultrasonic sensor and a second transmitting ultrasonic sensor, and the first transmitting ultrasonic sensor and the second transmitting ultrasonic sensor are arranged at the same depth position and are distributed at intervals of 180 degrees along the circumferential direction;

the lower transmitting array comprises a third transmitting ultrasonic sensor and a fourth transmitting ultrasonic sensor, the third transmitting ultrasonic sensor and the fourth transmitting ultrasonic sensor are arranged at the same depth position and are distributed at intervals of 180 degrees along the circumferential direction, and the radial direction corresponding to the first transmitting ultrasonic sensor is the same as the radial direction corresponding to the third transmitting ultrasonic sensor.

4. The ultrasonic imaging logging system of claim 3 wherein the receiving array comprises a plurality of sets of receiving stations spaced apart along the axial direction of the borehole wall, each set of receiving stations comprising a first receiving ultrasonic transducer and a second receiving ultrasonic transducer, the first receiving ultrasonic transducer and the second receiving ultrasonic transducer mounted at a same depth position and spaced apart 180 ° circumferentially,

the radial positions corresponding to all the first receiving ultrasonic sensors are the same, and the radial positions corresponding to the first receiving ultrasonic sensors are the same as the radial positions corresponding to the first transmitting ultrasonic sensors.

5. The ultrasonic imaging logging system of any one of claims 1-4, wherein the acquisition and control processing means comprises:

the receiving and transmitting integrated control circuit is used for synchronously exciting all the receiving and transmitting integrated ultrasonic sensors to transmit the first type of ultrasonic pulse waves and parallelly receiving the pulse echoes detected by all the sensors under the control of a first transmitting instruction;

the transmitting circuit is used for exciting the sensors in the upper transmitting array and the lower transmitting array to synchronously transmit the second type of ultrasonic pulse waves under the control of a second transmitting instruction;

the receiving circuit is used for receiving the ultrasonic pulse sliding wave train including sliding longitudinal waves, transverse waves and pseudo-Rayleigh waves detected by each sensor in the receiving array in parallel;

the acquisition module is used for acquiring the pulse echo or the ultrasonic pulse sliding wave train received by each channel in parallel;

and the main control module is used for sequentially sending the first transmitting instruction and the second transmitting instruction to the receiving-transmitting integrated control circuit and the transmitting circuit in a time-sharing manner when the drill collar rotates to a corresponding azimuth angle so as to receive the pulse echo and the ultrasonic pulse sliding wave train acquired at the corresponding azimuth angle and analyze and process the pulse echo and the ultrasonic pulse sliding wave train.

6. The ultrasonic imaging logging system of claim 5, wherein the acquisition and control processing device further comprises:

and the azimuth detection circuit is used for acquiring various logging tool face angle information, and extracting an azimuth measurement value corresponding to the current measurement point based on the information so as to transmit the azimuth measurement value to the main control module.

7. The ultrasonic imaging logging system of any one of claims 1-6, wherein the acquisition and control processing means comprises:

a data reading circuit connected with the ground device for reading the obtained analysis processing result in real time and transmitting the reading result to the ground device, wherein,

the ground device is used for calculating the geometrical shape of a borehole according to the acquired echo propagation time information of all-directional angles under different logging depths, evaluating the acoustic impedance characteristics of a borehole wall medium according to the acquired echo amplitude information of all-directional angles under different logging depths, obtaining a first type of circumferential imaging graph of the reflection characteristics of the borehole wall medium according to the analysis result of the geometrical shape of the borehole and the acoustic impedance characteristics of the borehole wall medium, and obtaining a second type of circumferential imaging graph representing the wave speed and attenuation of the borehole wall stratum according to the obtained longitudinal and transverse wave speed and ultrasonic attenuation characteristics of the borehole wall stratum under all-directional angles under different logging depths so as to determine the circumferential change of the wave speed of the stratum and evaluate and analyze the anisotropy of the stratum around the borehole wall.

8. The ultrasonic imaging well logging system according to any one of claims 1 to 7, wherein the acquisition and control processing device is mounted on the inner wall of a drill collar through a square prism framework and filled with high-temperature-resistant silica gel, wherein the drill collar is a non-magnetic drill collar which is arranged in a drilling fluid medium in a well hole and is connected with a downhole drilling tool assembly through a screw thread.

9. An ultrasonic imaging logging method for a borehole wall formation while drilling, the method being implemented by an ultrasonic imaging logging system as claimed in any one of claims 1 to 8, the ultrasonic imaging logging method comprising:

transmitting a first type of ultrasonic pulse wave to a well wall interface at the current drill collar rotation position, and receiving a pulse echo reflected from the interface;

transmitting a second type of ultrasonic pulse wave to the well wall stratum by each group of transmitting arrays in the current position along opposite radial directions respectively, and receiving an ultrasonic pulse sliding wave train which is transmitted through the stratum and refracted from drilling fluid in a well hole by the receiving array;

and analyzing and processing the acquired pulse echo and the ultrasonic pulse sliding wave train to respectively obtain the propagation time and amplitude of the echo, and the longitudinal and transverse wave velocity and ultrasonic attenuation data of the well wall stratum.

10. The ultrasonic imaging logging method of claim 9,

reading an analysis processing result obtained under the corresponding rotation direction in real time, and transmitting the reading result to the ground device;

calculating the geometrical shape of the borehole according to the acquired echo propagation time information of the omnibearing angle under different logging depths, and evaluating the acoustic impedance characteristic of the borehole wall medium according to the acquired echo amplitude information of the omnibearing angle under different logging depths, so as to obtain a first-class circumferential imaging graph of the reflection characteristic of the borehole wall medium according to the analysis result of the geometrical shape of the borehole and the acoustic impedance characteristic of the borehole wall medium;

and according to the acquired longitudinal and transverse wave velocities and ultrasonic attenuation characteristics of the borehole wall stratum at all angles under different logging depths, acquiring a second type of circumferential imaging graph representing the wave velocity and attenuation of the borehole wall stratum so as to determine the circumferential change of the stratum wave velocity, and evaluating and analyzing the anisotropy and anisotropy of the stratum around the borehole wall.

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