CN210460643U

CN210460643U - Hole diameter flow adjusting instrument

Info

Publication number: CN210460643U
Application number: CN201921142288.0U
Authority: CN
Inventors: 袁磊; 马瑞涛; 魏玉平; 来超
Original assignee: Xian Sitan Apparatus Co Ltd
Current assignee: Xian Sitan Apparatus Co Ltd
Priority date: 2019-07-19
Filing date: 2019-07-19
Publication date: 2020-05-05
Anticipated expiration: 2029-07-19

Abstract

The utility model discloses a hole diameter flow adjusting instrument, which comprises an ultrasonic flow nipple, a hole diameter measuring nipple and an adjusting control nipple which are connected in sequence, wherein the ultrasonic flow nipple comprises a flow probe and a flow control module which are electrically connected with each other; the well diameter measuring short section comprises a bendable well diameter measuring arm, a movable barrel, a fixed barrel, a spring, a central rod, a displacement sensor and a well diameter control module; the testing and adjusting control short section comprises a testing and adjusting control motor, a testing and adjusting transmission system, an adjusting arm assembly and a testing and adjusting control module, wherein the testing and adjusting control module is electrically connected with the flow control module, the well diameter control module and the testing and adjusting control motor, the testing and adjusting transmission system is connected with the testing and adjusting control motor and the adjusting arm assembly, and the free end of the adjusting arm assembly extends out of the testing and adjusting control short section. The caliper flow regulator can monitor the caliper and the flow in real time, so that the caliper can calibrate the flow value, and the flow test is more accurate.

Description

Hole diameter flow adjusting instrument

Technical Field

The utility model belongs to the technical field of the oil and gas surveys, concretely relates to hole diameter flow timing appearance.

Background

Oilfield flooding is an important means for supplementing energy to the stratum, maintaining the pressure of the stratum, improving the recovery ratio of the oilfield and maintaining the stable yield and high yield of the oilfield in the oilfield development process. At present, most oil fields in China are developed by adopting a water flooding mode, and the water flooding development is still the main mode for oil field development even for a long time in the future. Therefore, the excellent water injection effect has very important significance for scientific exploitation of oil fields. In the water injection operation process, the underground water injection flow is a parameter which is mainly referred to the water injection effect, and the accurate measurement of the data is an important step for researching the dynamic characteristic in the water injection process and checking the ground water injection process flow, and has important significance for analyzing whether the water injection achieves the expected effect.

There are many testing methods and measuring devices for measuring the flow rate of water injection process, among which, the flowmeter is the main measuring instrument. According to the actual construction condition of an oil field, in the process of flow measurement, the underground pipe column can generate inner diameter deformation due to the effects of collision, corrosion, deposition, wax deposition and other conditions.

However, the existing flow measurement methods are designed based on a uniform model with the upper and lower consistent sections in the pipe column, and the corrosion, scaling and deformation of the pipe column are not considered, so that the measured flow data has a certain error with the actual flow.

SUMMERY OF THE UTILITY MODEL

In order to solve the above-mentioned problem that exists among the prior art, the utility model provides a hole diameter flow timing appearance. The to-be-solved technical problem of the utility model is realized through following technical scheme:

the utility model provides a hole diameter flow adjusting instrument, which comprises an ultrasonic flow nipple, a hole diameter measuring nipple and an adjusting control nipple which are connected in sequence, wherein the ultrasonic flow nipple comprises a flow probe and a flow control module which are electrically connected with each other;

the well diameter measuring short section comprises a bendable well diameter measuring arm, a movable cylinder, a fixed cylinder, a spring and a central rod, wherein one end of the well diameter measuring arm is connected with the shell of the ultrasonic flow short section, and the other end of the well diameter measuring arm is connected with the movable cylinder; the spring is sleeved on the central rod, one end of the spring abuts against the movable cylinder, and the other end of the spring abuts against the fixed cylinder, so that the movable cylinder can move up and down relative to the fixed cylinder; the lower end of the central rod is provided with a displacement sensor and a well diameter control module, and the displacement sensor is electrically connected with the well diameter control module; one end of the center rod is connected with the movable cylinder, and the other end of the center rod is connected with the fixed cylinder;

the measuring and adjusting control short section comprises a measuring and adjusting control motor, a measuring and adjusting transmission system, an adjusting arm assembly and a measuring and adjusting control module, wherein the measuring and adjusting control module is electrically connected with the flow control module, the hole diameter control module and the measuring and adjusting control motor respectively, the measuring and adjusting transmission system is connected with the measuring and adjusting control motor and the adjusting arm assembly, and the free end of the adjusting arm assembly can obliquely extend out of the measuring and adjusting control short section according to the driving of the measuring and adjusting transmission system.

The utility model discloses an embodiment, supersound flow nipple joint with between the nipple joint is measured to the well diameter, and the nipple joint is measured to the well diameter with link to each other through leimo four-core coaxial socket and plug respectively between the measure and regulate control nipple joint.

The utility model discloses an in the embodiment, flow probe sets up in the top of supersound flow nipple joint, and flow control module sets up in the flow probe below, and flow control module electricity is connected survey and regulate the control nipple joint.

In one embodiment of the invention, the caliper measuring arm comprises a first arm and a second arm that are articulated, wherein the first arm is connected to the housing of the flow control module and the second arm is connected to the side wall of the movable barrel.

The utility model discloses an embodiment, the nipple joint is measured to the hole diameter includes a plurality of hole diameter and measures the arm, a plurality of hole diameter measure the arm around the circumference evenly distributed of nipple joint is measured to the hole diameter.

The utility model discloses an embodiment, the nipple joint is measured to the well diameter still includes the locking ring, the locking ring is in along circumference joint on the inner wall of a movable section of thick bamboo, well core rod stretches into the locking ring is in with the restriction in the inner chamber of a movable section of thick bamboo.

In an embodiment of the utility model, the upper end of well core rod is passed the inner chamber of a movable section of thick bamboo is connected to supersound flow nipple joint, the other end along the axial stretch into fixed connection to the inner chamber of a fixed section of thick bamboo and with a fixed section of thick bamboo fastening connection.

The utility model discloses an embodiment, the measure and regulate control nipple joint still includes the guide, the guide is located the below of regulating arm subassembly.

The utility model discloses an in one embodiment, test and debug the control nipple joint and still include the magnetism setting element, test and debug control module still includes magnetism location acquisition circuit, magnetism setting element electricity is connected magnetism location acquisition circuit.

Compared with the prior art, the beneficial effects of the utility model reside in that:

1. the utility model discloses a hole diameter flow timing appearance adopts split type structure, measures the nipple joint and measures the three nipple joint of accent control nipple joint by supersound flow nipple joint, hole diameter and constitutes, and three nipple joint can both be dismantled, easily changes, is convenient for maintain and carry.

2. The hole diameter measuring nipple of the hole diameter flow adjusting instrument comprises a bendable hole diameter measuring arm and can be bent into different angles according to the change of the hole diameter in real time, so that real data of the hole diameter are obtained in real time, and flow numerical values are calibrated through the real hole diameter data, so that the flow calibration is more accurate.

The present invention will be described in further detail with reference to the accompanying drawings and examples.

Drawings

Fig. 1 is a schematic structural diagram of a hole diameter flow rate adjustment gauge provided in an embodiment of the present invention;

fig. 2 is a schematic partial cross-sectional view of a short section for measuring the borehole diameter provided by an embodiment of the present invention;

fig. 3 is a schematic connection diagram of a control module of a hole diameter flow rate calibration instrument according to an embodiment of the present invention.

Description of reference numerals:

1-ultrasonic flow nipple; 11-a flow probe; 12-a flow control module; 2-measuring the short section of the well diameter; 21-a caliper measuring arm; 22-a movable cylinder; 23-a stationary cylinder; 24-a spring; 25-a center rod; 26-a displacement sensor; 27-a caliper control module; 28-locking ring; 3-measuring and adjusting the control short section; 31-measuring and adjusting a control motor; 32-measuring and adjusting a transmission system; 33-an adjustment arm assembly; 34-a test and adjustment control module; 35-a magnetic positioning element; 36-a guide; 4-ground control system.

Detailed Description

In order to further explain the technical means and effects of the present invention adopted to achieve the objectives of the present invention, the following description will be made in conjunction with the accompanying drawings and the detailed description of the preferred embodiments of the present invention with reference to the well diameter flow rate adjustment instrument.

The foregoing and other technical matters, features and effects of the present invention will be apparent from the following detailed description of the embodiments, which is to be read in connection with the accompanying drawings. The technical means and effects of the present invention to achieve the predetermined objects can be more deeply and specifically understood through the description of the specific embodiments, however, the attached drawings are only for reference and description and are not intended to limit the technical solution of the present invention.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a hole diameter flow rate adjustment instrument according to an embodiment of the present invention. The hole diameter flow adjusting instrument of this embodiment includes ultrasonic flow nipple 1, hole diameter measurement nipple 2 and measure and adjust control nipple 3 that link together in proper order along axial direction with can dismantling the mode. Between the nipple joint 2 is measured to supersound flow nipple joint 1 and well diameter to and between nipple joint 2 is measured to well diameter and the measure and regulate control nipple joint 3 for example can link to each other through leimo four-core coaxial socket and plug respectively, guarantee that three nipple joint can dismantle wantonly, convenient maintenance and change.

The ultrasonic flow nipple 1 comprises a flow probe 11 and a flow control module 12, wherein the flow probe 11 is arranged at the top end of the ultrasonic flow nipple 1, and the flow control module 12 is arranged below the flow probe 11. Further, the flow probe 11 and the flow control module 12 are electrically connected to each other, and the flow control module 12 is electrically connected to the gauging control sub 3. The flow probe 11 can send and receive ultrasonic signals, acquire downhole flow information according to the signals, and then send the flow information to the flow control module 12; flow control module 12 can gather and handle flow signal to process into flow data with it, and send to measure and regulate control nipple joint 3, in this embodiment, measure and regulate control nipple joint 3 can be connected to ground control system, and will flow data send to ground control system.

The hole diameter measuring short section 2 comprises a bendable hole diameter measuring arm 21, a movable barrel 22, a fixed barrel 23, a spring 24, a central rod 25, a displacement sensor 26 and a hole diameter control module 27. The ultrasonic flow nipple joint comprises a plurality of well diameter measuring arms 21, wherein the plurality of well diameter measuring arms 21 are uniformly distributed around the circumference of a well diameter measuring nipple 2, one end of each well diameter measuring arm 21 is connected with an outer shell of the ultrasonic flow nipple 1, and the other end of each well diameter measuring arm 21 is connected with a movable barrel 22. As shown in fig. 1, the caliper measuring sub 2 of this embodiment includes three bendable caliper measuring arms 21, which are uniformly distributed at an included angle of 120 ° outside the caliper measuring sub 2.

Further, please refer to fig. 2, fig. 2 is a schematic partial cross-sectional view of a short section for measuring the borehole diameter according to an embodiment of the present invention. The caliper arm 21 of the present embodiment includes a first arm portion 211 and a second arm portion 212 that are hinged, wherein the first arm portion 211 is rotatably connected to the housing of the flow control module 12, the second arm portion 212 is rotatably connected to the side wall of the movable cylinder 22, and the connecting portion of the first arm portion 211 and the second arm portion 212 protrudes outward so as to form an angle.

A spring 24 is fitted over the center rod 25, and one end of the spring 24 abuts against the movable barrel 22 and the other end abuts against the fixed barrel 23, so that the movable barrel 22 can move up and down with respect to the fixed barrel 23. The center rod 25 is connected to the movable cylinder 22 at one end and to the fixed cylinder 23 at the other end. In this embodiment, the upper end of the center rod 25 passes through the inner cavity of the movable cylinder 22 and is connected to the ultrasonic flow nipple 1, and the other end axially extends into the inner cavity fixedly connected to the fixed cylinder 23 and is tightly connected with the fixed cylinder 23. The displacement sensor 26 and the hole diameter control module 27 are arranged at the lower end of the central rod 25, and the displacement sensor 26 is electrically connected with the hole diameter control module 27.

Further, the well diameter measuring short joint 2 further comprises a locking ring 28, the locking ring 28 is clamped on the inner wall of the movable cylinder 22 along the circumferential direction, and the central rod 25 extends into the locking ring 28 to be limited in the inner cavity of the movable cylinder 22, so that the whole structure has higher stability during the movement process.

As described above, in an actual oil exploitation process, according to actual construction conditions on an oil field, during a flow measurement process, a downhole string may be deformed in an inner diameter due to various situations such as collision, corrosion, deposition, and wax deposition. The existing flow measuring method is designed based on a uniform model with the upper and lower consistent sections in the pipe column, and the conditions of corrosion, scaling and deformation of the pipe column are not considered, so that the measured flow data has a certain error with the actual flow.

The caliper gauge of this embodiment includes a caliper measuring arm 21 extending out of the gauge body, and in a normal state, the caliper measuring arm 21 is in a normally open state due to the fact that the movable cylinder 22 is pressed by the thrust of the spring 24, and the movable cylinder 22 is connected with the central rod 25 through the locking ring 28 to drive the displacement sensor 26 to stretch, so that the displacement sensor 26 is in a maximum position state. In the instrument downhole process, the borehole diameter measuring arm 21 is in real-time contact with the borehole wall and is extruded by the borehole wall, so that the borehole diameter measuring arm 21 tends to move inwards along the axial direction of the borehole diameter flow regulator, namely, the hinged part between the first arm part 211 and the second arm part 212 rotates relatively, an included angle between the first arm part 211 and the second arm part 212 is increased, the movable cylinder 22 is further pushed to overcome the elastic force of the spring 24 and then drive the central rod 25 to move downwards, then the displacement sensor 26 positioned at the lower end of the central rod 25 also moves downwards, the position of the displacement sensor changes to form a displacement signal, and the displacement signal is processed into borehole diameter data after being collected by the borehole diameter control module 27. In this embodiment, the hole diameter control module 27 is connected to the measurement and adjustment control sub 3, and the hole diameter data is sent to the ground control system through the measurement and adjustment control sub 3.

Meanwhile, the well diameter measuring nipple 2 is arranged below the ultrasonic flow nipple 1, and has the function of stabilizing the flow probe 11, so that the fluid flow is ensured, and the measured flow is more accurate.

Referring to fig. 1 and fig. 3, fig. 3 is a schematic connection diagram of a control module of a caliper/flowmeter according to an embodiment of the present invention. The measurement and adjustment control short section 3 comprises a measurement and adjustment control motor 31, a measurement and adjustment transmission system 32, an adjusting arm assembly 33 and a measurement and adjustment control module 34, wherein the measurement and adjustment control module 34 is electrically connected with the flow control module 12, the hole diameter control module 27 and the measurement and adjustment control motor 31, the measurement and adjustment transmission system 32 is connected with the measurement and adjustment control motor 31 and the adjusting arm assembly 33, and the free end of the adjusting arm assembly 33 extends out of the measurement and adjustment control short section 3. In the present embodiment, the metering drive train 32 may be a drive gear set or other conventional drive assembly.

In this embodiment, the measurement and adjustment control module 34 is disposed below the adjustment arm assembly 33, includes a decoding circuit and a code sending circuit, and is electrically connected to the surface control system 4 for communicating with the surface control system 4, the flow control module 12, and the hole diameter control module 27. Similarly, the flow control module 12 and the hole diameter control module 27 may also include a decoding circuit and a code sending circuit, respectively, to communicate with the relevant components, and the specific processes have been described in detail above and are not described again here.

In addition, the testing and adjusting control module 34 further includes a driving circuit, which is electrically connected to the decoding circuit and the code sending circuit, and is configured to drive the adjusting arm assembly 33 to open according to the adjusting arm assembly opening signal sent by the ground control system 4, and drive the testing and adjusting control motor 31 to rotate according to the testing and adjusting control motor driving signal sent by the ground control system 4.

Specifically, the measurement and adjustment control module 34 can control the positive and negative rotation of the measurement and adjustment control motor 31, and the measurement and adjustment control motor 31 drives the measurement and adjustment transmission system 32 to rotate, so that the adjusting arm assembly 33 can complete the arm opening and closing and positive and negative adjustment actions, so as to be in butt joint with the adjusting arm assembly 33 and the eccentric water distributor, and perform the water nozzle positive adjustment and negative adjustment operations of the eccentric water distributor through the adjusting arm assembly 33. It should be noted that the measurement and adjustment control module 34 is not only responsible for the control, state detection and cable head signal transmission of the measurement and adjustment control motor 31, but also responsible for packaging the flow data from the flow control module 12 and the hole diameter data from the hole diameter control module 27 and then sending the packaged data to the ground control system 4. And the ground control system 4 judges and sends a command after decision according to the flow data after the well diameter compensation, and controls the water nozzle of the underground eccentric water distributor to be opened and closed in a large or small way, so that the measurement and adjustment of the stratified water injection are realized. Specifically, after receiving a measurement and adjustment control motor driving signal sent by the ground control system 4, the driving circuit drives the measurement and adjustment control motor 31 to perform forward rotation, reverse rotation and stop actions, and the forward rotation, reverse rotation and stop actions of the measurement and adjustment control motor 31 drive the measurement and adjustment transmission system 32, so as to drive the adjusting arm assembly 33 to realize functions of opening and closing an arm, positively adjusting a water nozzle, negatively adjusting the water nozzle and the like.

Further, the measurement and adjustment control sub 3 further comprises a guide piece 36, the guide piece 36 is located below the adjusting arm assembly 33, and after the adjusting arm assembly 33 is opened, the guide piece 36 is in butt joint with a downhole eccentric water distributor for use. Further, the measurement and adjustment control pup joint 3 further comprises a magnetic positioning piece 35, the measurement and adjustment control module 34 further comprises a magnetic positioning acquisition circuit, and the magnetic positioning piece 35 is electrically connected with the magnetic positioning acquisition circuit. The magnetic positioning acquisition circuit can acquire signals on the magnetic positioning piece 35, and the acquired magnetic positioning signals can judge the underground working position of the instrument.

In this embodiment, among three independent short sections, i.e., the ultrasonic flow short section 1, the hole diameter measuring short section 2 and the measurement and adjustment control short section 3, only the measurement and adjustment control short section 3 can directly communicate with a ground control system, and the other two short sections are used as slaves of the measurement and adjustment control short section 3 and are controlled by the slaves. The hole diameter flow rate adjusting instrument can complete the functions of adjusting the water nozzle and adjusting the flow rate in field use.

The water nozzle adjusting process:

the utility model discloses a well diameter flow timing appearance is after going into the well, the well depth data and the preliminary judgement of magnetism locating signal of earlier surveying through ground control system the roughly position of eccentric injection mandrel, lift this well diameter flow timing appearance about 5-10m to the injection mandrel top, then send the instruction and for surveying and transferring control module 34, make it open regulating arm subassembly 33, transfer well diameter flow timing appearance, through the guide effect of guide assembly 36 for regulating arm subassembly 33 and injection mandrel butt joint, so far, can carry out the positive accent and the negative accent operation of eccentric injection mandrel water injection well choke.

Flow adjustment and calibration processes:

in the process of descending the well, the well diameter flow adjusting gauge measures underground flow data and well diameter data in real time through the ultrasonic flow nipple 1 and the well diameter measuring nipple 2, and transmits the flow data and the well diameter data to a ground control system through the measuring and adjusting control module 34. The ground control system utilizes a compensation formula to compensate the flow through the measured hole diameter data, the compensated flow data is actually measured data, the underground water injection condition can be analyzed through the data, and then the measurement and adjustment control module 34 is guided to control the parts such as the adjusting arm assembly 33, the adjustment operation of the water nozzle is carried out, and further the water distribution amount among different stratums can be guided.

After the water nozzle adjustment and flow adjustment process is finished, the hole diameter flow adjustment instrument is lifted up, and then the test of other layers is carried out.

It should be noted that, because the utility model discloses a 3 work nipple joints of hole diameter flow timing appearance are independent design, measure and transfer process and timing process are two mutually independent processes, consequently the utility model discloses a measure and transfer process and hole diameter flow timing process do not have earlier order, can go on simultaneously.

The hole diameter flow adjustment instrument of this embodiment adopts split type structure, measures the nipple joint and measure and regulate the three nipple joint of control nipple joint by supersound flow nipple joint, hole diameter and constitutes, and total length is less than 2000mm, and three nipple joint can both be dismantled, easily changes, is convenient for maintain and carry. In addition, the hole diameter measuring nipple of the hole diameter flow adjusting instrument comprises a bendable hole diameter measuring arm and can be bent into different angles according to the change of the hole diameter in real time, so that real data of the hole diameter are obtained in real time, and flow numerical values are calibrated through the real hole diameter data, so that the flow calibration is more accurate.

The foregoing is a more detailed description of the present invention, taken in conjunction with the specific preferred embodiments thereof, and it is not intended that the invention be limited to the specific embodiments shown and described. To the utility model belongs to the technical field of ordinary technical personnel, do not deviate from the utility model discloses under the prerequisite of design, can also make a plurality of simple deductions or replacement, all should regard as belonging to the utility model discloses a protection scope.

Claims

1. A hole diameter flow adjusting gauge is characterized by comprising an ultrasonic flow nipple (1), a hole diameter measuring nipple (2) and an adjusting control nipple (3) which are sequentially connected, wherein the ultrasonic flow nipple (1) comprises a flow probe (11) and a flow control module (12) which are electrically connected with each other;

the well diameter measuring short section (2) comprises a bendable well diameter measuring arm (21), a movable barrel (22), a fixed barrel (23), a spring (24) and a central rod (25), wherein one end of the well diameter measuring arm (21) is connected with the shell of the ultrasonic flow short section (1), and the other end of the well diameter measuring arm is connected with the movable barrel (22); the spring (24) is sleeved on the central rod (25), one end of the spring abuts against the movable cylinder (22), and the other end of the spring abuts against the fixed cylinder (23), so that the movable cylinder (22) can move up and down relative to the fixed cylinder (23); a displacement sensor (26) and a well diameter control module (27) are arranged at the lower end of the central rod (25), and the displacement sensor (26) is electrically connected with the well diameter control module (27); one end of the central rod (25) is connected with the movable cylinder (22), and the other end of the central rod is connected with the fixed cylinder (23);

the measurement and adjustment control short section (3) comprises a measurement and adjustment control motor (31), a measurement and adjustment transmission system (32), an adjusting arm component (33) and a measurement and adjustment control module (34), wherein the measurement and adjustment control module (34) is respectively and electrically connected with the flow control module (12), the well diameter control module (27) and the measurement and adjustment control motor (31), the measurement and adjustment transmission system (32) is connected with the measurement and adjustment control motor (31) and the adjusting arm component (33), and the free end of the adjusting arm component (33) can obliquely extend out of the measurement and adjustment control short section (3) according to the driving of the measurement and adjustment transmission system (32).

2. The hole diameter flow regulator according to claim 1, wherein the ultrasonic flow nipple (1) and the hole diameter measuring nipple (2) and the regulation control nipple (3) are respectively connected through a rammo four-core coaxial socket and plug.

3. The hole diameter flow regulator according to claim 1, wherein the flow probe (11) is arranged at the top end of the ultrasonic flow nipple (1), the flow control module (12) is arranged below the flow probe (11), and the flow control module (12) is electrically connected with the measurement and regulation control nipple (3).

4. The hole diameter flow gauge according to claim 1, characterized in that the hole diameter measuring arm (21) comprises a first arm (211) and a second arm (212) which are hinged, wherein the first arm (211) is connected to the housing of the flow control module (12) and the second arm (212) is connected to the side wall of the movable barrel (22).

5. The hole diameter flow rate gauge according to claim 1, characterized in that the hole diameter measuring sub (2) comprises a plurality of hole diameter measuring arms (21), the plurality of hole diameter measuring arms (21) being evenly distributed around the circumference of the hole diameter measuring sub (2).

6. The hole diameter flow gauge according to claim 1, wherein the hole diameter measuring nipple (2) further comprises a locking ring (28), the locking ring (28) is circumferentially clamped on the inner wall of the movable barrel (22), and the central rod (25) extends into the locking ring (28) to be confined in the inner cavity of the movable barrel (22).

7. The hole diameter flow regulator according to claim 1, characterized in that the upper end of the center rod (25) is connected to the ultrasonic flow nipple (1) through the inner cavity of the movable cylinder (22), and the other end axially extends into the inner cavity fixedly connected to the fixed cylinder (23) and is tightly connected with the fixed cylinder (23).

8. The hole diameter flow meter according to claim 1, characterized in that the meter control sub (3) further comprises a guide (36), the guide (36) being located below the adjustment arm assembly (33).

9. The caliper flow adjuster according to any one of claims 1 to 8, wherein the measurement and adjustment control sub (3) further comprises a magnetic positioning element (35), the measurement and adjustment control module (34) further comprises a magnetic positioning acquisition circuit, and the magnetic positioning element (35) is electrically connected with the magnetic positioning acquisition circuit.