CN112000042A - Multi-electric fracturing device equal network control system and method - Google Patents

Abstract

The invention provides an equal network control system for a plurality of fracturing devices, wherein output pipelines of the plurality of fracturing devices are mutually connected through a main pipeline, the fracturing devices are provided with main control devices, the main control devices are electrically connected with a motor, and the main control devices of the fracturing devices are mutually connected through an industrial field bus to form an adaptive equal network. Time synchronization of each master control device; optionally, a node sends out an initial instruction of binding time; each node receives the initial instruction, and returns to the node sending the initial instruction after the difference between the receiving time and the time bound in the instruction is obtained; averaging the time differences; taking the master control device closest to the average number as a master node; the selection of the master node in the equal network is realized through the steps. Because of adopting the adaptive equal network structure, the dependence on the control of an upper computer is greatly reduced, and the flexible control is realized. The robustness of a multi-electric fracturing device equipment group can be greatly improved, and the occurrence probability of shutdown faults is reduced.

Description

Multi-electric fracturing device equal network control system and method

Technical Field

The invention relates to the field of petroleum drilling and production equipment, in particular to a multi-electric fracturing device equal network control system and a method.

Background

The fracturing operation is a main measure for increasing and stabilizing yield in the exploration and development of oil and gas fields, and a plurality of high-power fracturing devices are utilized to fracture reservoir rocks and form a flow guide channel. With the development of ultra-deep well and horizontal well technologies, the power of the needed fracturing unit is increased, and the weight and the volume of a single fracturing device are increased. For example, the output pressure of the existing equipment reaches 175Mpa, and higher requirements are also put on the clutch in the equipment due to higher pressure. Chinese patent document CN107237617A describes an electrically driven fracturing device with a single-machine dual-pump structure, in which two pump head assemblies are driven by one motor to operate, and the friction plate assembly of the clutch needs to be hydraulically driven to switch between a disengaged state and an engaged state.

In the prior art, more electric fracturing devices are needed to form an equipment group to realize larger fracturing fluid flow output. With the increase of the output pressure, the difficulty of controlling the equipment group of the multi-fracturing device is greatly increased, and the difficulty of controlling the output pressure in a small fluctuation range is very high. Adopt the host computer to control usually among the prior art, the problem that exists is that, the problem that host computer self appears will lead to the work of whole equipment group to stop, causes great economic loss easily. And the data transmission delay between the upper computer and each electric fracturing device results in either low control accuracy or very expensive implementation, for example, providing a high-accuracy external clock as a reference.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a multi-electric fracturing device equal network control system and method, which can greatly improve the robustness of a multi-electric fracturing device equipment group and reduce the occurrence probability of shutdown faults. In the preferred scheme, the cost of the control system can be reduced, the control difficulty is reduced, and the stability of the output pressure of the multi-electric fracturing device equipment group is improved.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: the utility model provides a many fracturing units equal network control system, the output pipeline of a plurality of fracturing units interconnects through the main line, and the fracturing unit is equipped with master control unit, and master control unit and motor electricity are connected, and the master control unit of each fracturing unit interconnects through industrial field bus and constitutes self-adaptation equal network.

In the preferred scheme, the motor is a double-extension-shaft motor, and two ends of a motor shaft are respectively connected with the pump head through clutches;

the pump head is 3, 4, 5 or 6 cylinders.

In a preferred scheme, the industrial field bus is also electrically connected with an industrial personal computer for collecting and sending data.

A control method of the multi-electric fracturing device equal network control system comprises the following steps:

s1, time synchronization of each master control device;

s2, optionally sending an initial instruction of binding time by a node;

s3, each node receives the initial instruction, and returns to the node sending the initial instruction after the difference between the receiving time and the time bound in the instruction is obtained;

s4, averaging each time difference;

s5, taking the master control device closest to the average number as a master node;

the selection of the master node in the equal network is realized through the steps.

Preferably, the method further includes S01, performing self-test on each master control device, and evaluating the robustness of the master control device, where the evaluation parameters include computing power, storage capacity, operating age and operating temperature, and the master control device whose robustness is lower than a preset value is restricted to be qualified as the master node.

In a preferred embodiment, if the remaining master controllers have a robustness lower than a predetermined value, the master controller with the highest robustness is selected as the master node.

Preferably, before step S1, the method further includes the step of confirming whether the master node exists in the equal network.

In a preferred embodiment, in step S1, the initiating node sends a segment of clock pulse, and the receiving node adjusts its own clock according to the clock pulse to perform synchronization;

and gradually increasing the frequency of the clock pulse until reaching the precision limit of each master control device.

In a preferred embodiment, the method further comprises the following steps:

s6, the main node determines the number of each main control device;

s7, the main node performs circumferential indexing of the phase according to the total number of the main control devices;

s8, the master node sends the indexing phase angle to each slave node;

s9, the master node and the slave nodes are started in sequence according to the sequence of the phase angles;

s10, issuing the rotating speed and the real-time phase angle by the master node every other time period;

s11, the slave node follows according to the issued rotating speed, and the real-time phase angle is converted into the self following phase angle for closed-loop control;

through the steps, the output pressure fluctuation stability under the equal network control of the multiple electric fracturing devices is realized.

In the preferred scheme, in the working cycle of the master node, if the slave node is added or withdrawn, the steps S6-S11 are executed again;

when the master node exits, the process goes to step S1 to reselect the master node.

According to the system and the method for controlling the multilevel hydraulic fracturing device equal network, by adopting the scheme, the dependence on the upper computer control is greatly reduced due to the adoption of the self-adaptive equal network structure, and the flexible control is realized. The fault of the upper computer does not affect the work of the multi-electric fracturing device equipment group, so that the robustness of the multi-electric fracturing device equipment group can be greatly improved, and the probability of shutdown faults is reduced. In the preferred scheme, upper computer control is cancelled, so that the cost of a control system, particularly the cost of a software part, can be reduced, and the control difficulty is reduced. The stability of the output pressure of the multi-electric fracturing device equipment group is improved by the advantage of low time delay of the equal network structure.

Drawings

The invention is further illustrated by the following examples in conjunction with the accompanying drawings:

fig. 1 is a schematic diagram of the overall structure of an electric fracturing apparatus equipment group according to the present invention.

Fig. 2 is a schematic structural diagram of a single electric fracturing device in the invention.

Fig. 3 is a schematic view of a connection structure of the main control device of the present invention.

FIG. 4 is a schematic view of a plurality of master control devices of the present invention indexed circumferentially.

Fig. 5 is a schematic diagram of the output pressure of a single electric fracturing device of the present invention.

Fig. 6 is a schematic diagram of the output pressure of the electric fracturing unit equipment group in the present invention.

Fig. 7 is a schematic diagram of output pressure fluctuations for the group of electrically operated fracturing units of the present invention.

Fig. 8 is a flowchart when determining a master node in the present invention.

FIG. 9 is a schematic diagram of clock synchronization according to the present invention.

Fig. 10 is a flow chart of the present invention for controlling the main control devices to be uniformly distributed along the circumference in phase.

In the figure: the system comprises a fracturing device 1, a motor 2, a pump head 3, an electrical cabinet 4, a main control device 5, a clock 51, a control part 52, a network part 53, a clutch 6 and an industrial field bus 7.

Detailed Description

Example 1:

as shown in fig. 1 to 3, in the multi-electric fracturing device equal network control system, output pipelines of a plurality of fracturing devices 1 are connected with each other through a main pipeline, the main pipeline is connected with a wellhead, the fracturing devices 1 are provided with main control devices 5, the main control devices 5 are electrically connected with a motor 2, and the main control devices 5 of the fracturing devices 1 are connected with each other through an industrial field bus 7 to form an adaptive equal network. By adopting the scheme of the self-adaptive equal network, the control of an upper computer is omitted, and the influence on the operation of an equipment group consisting of a plurality of electric fracturing devices due to the upper computer is avoided. In the equipment group of the electric fracturing device, even if part of equipment fails, the equipment can easily quit the self-adaptive equal network for maintenance, and the rest electric fracturing devices can be adjusted in a self-adaptive mode to continuously complete the set work.

The industrial field BUS 7 comprises one of PROFIBUS, EtherCAT, Interbus, CANopen, ControlNet , Ethernet, PROFINET, Modbus, RS232/RS485, EPA, G-link, Symotion and NCUC-BUS.

In a preferred scheme, as shown in fig. 2, the motor 2 is a double-extension-shaft motor, and two ends of a shaft of the motor 2 are respectively connected with the pump head 3 through clutches 6; the pump head is 3, 4, 5 or 6 cylinders. In this example, each pump head 3 is preferably of a 5-cylinder construction.

In a preferred embodiment, the industrial fieldbus 7 is also electrically connected to an industrial control computer for collecting and transmitting data. With this structure, it is convenient to collect the operation data of each equipment group or realize remote control, but the control is separated from the adaptive equal network, and more similar to some advanced commands, such as increasing or decreasing pressure, increasing or decreasing flow and so on.

Example 2:

on the basis of embodiment 1, as shown in fig. 8 and 9, a control method adopting the above-mentioned multi-electric fracturing device equal network control system includes the following steps:

s1, synchronizing the time of each master control device 5;

in a preferred embodiment, in step S1, the initiating node sends a segment of clock pulse, and the receiving node adjusts its own clock according to the clock pulse to perform synchronization;

and gradually increasing the frequency of the clock pulse until reaching the precision limit of each master control device. In chinese patent 201410019821.X, a wireless sensor assembly and a TDMA ad hoc network implementation method are described, wherein a scheme for implementing synchronization of each node through time slot control is mentioned. In this example, the clock synchronization is achieved step by clock pulses. As shown in fig. 9, the initiating node gives a clock, and other nodes are approximately adjusted to be consistent according to the clock, but the synchronization precision is low at this time, and the influence caused by network delay, operation delay and operation delay is not considered. A clock pulse is sent, for example, initially at a frequency of seconds, i.e., a square waveform per second, and then the frequency is increased step by step, for example, 1/2 seconds, 1/5 seconds, 1/10 seconds, 1/50 seconds, 1/100 seconds, until the limit of the accuracy of the master control device is reached. This step achieves accurate synchronization of the clocks. But also very fast.

S2, optionally sending an initial instruction of binding time by a node; the optional node is a node qualified to participate in the main node election, and may select one main control device 5 with the largest or smallest serial number, or the highest robustness, or the random selection, and the sent initial instruction is a code, which at least includes an address code, a time code and an event code, the address code is convenient for receiving returned data, the time code is used for operation, and the event code is used for informing other nodes that the instruction is the initial instruction.

S3, each node receives the initial instruction, and returns to the node sending the initial instruction after the difference between the receiving time of each node and the time bound in the instruction is obtained; according to the scheme, the time delay of each node relative to the initial node can be roughly obtained. The delay here includes the sum of network delay, computation delay and operation delay.

S4, averaging each time difference;

s5, taking the master control device closest to the average number as a master node; the probability of multiple juxtaposed near-average masters appearing is very low due to the sufficiently high accuracy, and of course, can be selected in an optional manner if they occur. Since delay is inevitable, it is advantageous to select a master device with a central delay as the master node to reduce the accumulated error of the delay.

The selection of the master node in the equal network is realized through the steps.

In a further preferred scheme, the nodes which issue the initial instructions may be sequentially selected, and the steps of S1 to S5 may be performed in multiple rounds, with the master node which has the most number of times of selection as the final master node.

In a preferred scheme, the method further comprises the step of S01, performing self-test on each master control device, and evaluating the robustness of the master control device, wherein evaluation parameters comprise computing capacity, storage capacity, working age and working temperature, and the master control device with the robustness lower than a preset value is limited to be qualified as a master node;

in a preferred embodiment, if the remaining master controllers have a robustness lower than a predetermined value, the master controller with the highest robustness is selected as the master node. By the scheme, the breakdown resistance of the whole system is further improved.

Preferably, before step S1, the method further includes the step of confirming whether the master node exists in the equal network. A time period may be preset in which data transmitted from the master node is not received, and step S1 is initiated.

Example 3:

independently or on the basis of the embodiments 1-2, a preferable scheme is as shown in fig. 10, and the method further comprises the following steps:

s6, the main node determines the number of each main control device 5;

s7, the master node performs circumferential indexing of the phase according to the total number of the master control device 5; as shown in fig. 4. It should be noted that fig. 4 is merely an example for easy observation and understanding. In practice, each electric fracturing device has a plurality of cylinders, for example, from 1 to 12, and each cylinder of each electric fracturing device is distributed in a complete circle, that is, in practice, the division angle a in the figure is much smaller than that shown in the figure. Taking 5 cylinders as an example, the phase angles of 5 cylinders are generally distributed equally on the circumference, and the phase angle of each cylinder on the circumference is 72 degrees, but when there are 20 groups of 5 cylinder heads forming an array, the problem of overlapping the phase angles of the cylinders is easy to exist, if the phase angles of a plurality of cylinders are relatively close to each other, a pressure peak appears on the output pressure value, and if no cylinder output pressure exists in a section of the circumference, a pressure valley appears on the output pressure value, which is not favorable for the normal operation of the equipment, especially the damage to the high-pressure manifold is large. If the phase angles of the cylinders can be evenly distributed on the circumference, a medium with stable pressure value can be output, and the service life of the equipment is prolonged. Thus, when there is an array of 20 groups of 5 cylinder heads, the phase angles of the cylinders are distributed with an angular difference of 3.6 °.

S8, the master node sends the indexing phase angle to each slave node; the index phase refers to a phase difference between the slave node and the master node.

S9, the master node and the slave nodes are started in sequence according to the sequence of the preset phase angles;

s10, issuing the rotating speed and the real-time phase angle by the master node every other time period;

s11, the slave nodes follow according to the rotating speed issued by the master node, and the real-time phase angle is converted into the self following phase angle for closed-loop control; the slave node firstly follows the rotating speed, and after the rotating speed approximately reaches the rotating speed of the master node, the phase angle is adjusted in a following mode according to the phase angle of the master node. Further preferably, in the conversion, the delay of the network time is calculated as a correction coefficient, thereby further improving the control accuracy.

When a plurality of electric fracturing units are operated simultaneously as in fig. 6, the theoretical distribution of the cylinders should be as shown in fig. 6 to ensure as uniform as possible. As shown in FIG. 7, the purpose of steps 6-11 is to make the pressure difference Q1 as small as possible. Thereby ensuring a smooth output pressure. In fig. 5 and 6, the ordinate represents pressure and the abscissa represents phase of the circumference. In fig. 7, the vertical axis represents pressure, and the horizontal axis represents time.

Through the steps, the output pressure fluctuation stability under the equal network control of the multiple electric fracturing devices is realized. The solution in this example can be implemented independently.

In the preferred scheme, in the working cycle of the master node, if the slave node is added or withdrawn, the steps S6-S11 are executed again; the solution in this example can be implemented independently.

In a further preferred step, when the master node exits, the process goes to step S1 to reselect the master node.

The above-described embodiments are merely preferred embodiments of the present invention, and should not be construed as limiting the present invention, and the scope of the present invention is defined by the claims, and equivalents including technical features described in the claims. I.e., equivalent alterations and modifications within the scope hereof, are also intended to be within the scope of the invention. For the sake of brevity, all the combinations of the embodiments are not exemplified, and therefore, the technical features of the embodiments can be combined with each other to generate more technical solutions without conflict.

Claims (10)

1. The utility model provides a many electric fracturing unit equal network control system, the output pipeline of a plurality of fracturing unit (1) passes through main pipeline interconnect, and fracturing unit (1) is equipped with master control set (5), and master control set (5) are connected characterized by with motor (2) electricity:

the main control devices (5) of all the fracturing devices (1) are mutually connected through an industrial field bus (7) to form a self-adaptive equal network.

2. The system of claim 1, wherein the network controller comprises: the motor (2) is a double-extension-shaft motor, and two ends of a shaft of the motor (2) are respectively connected with the pump head (3) through a clutch (6);

the pump head is 3, 4, 5 or 6 cylinders.

3. The system of claim 1 or 2, wherein the network controller comprises: the industrial field bus (7) is also electrically connected with an industrial personal computer for collecting and sending data.

4. A control method using the multilevel hydraulic fracturing device equal network control system according to any one of claims 1 to 3, comprising the steps of:

s1, time synchronization of each master control device (5);

s2, optionally sending an initial instruction of binding time by a node;

s3, each node receives the initial instruction, and returns to the node sending the initial instruction after the difference between the receiving time and the time bound in the instruction is obtained;

s4, averaging each time difference;

s5, taking the master control device closest to the average number as a master node;

the selection of the master node in the equal network is realized through the steps.

5. The method for controlling a multilevel hydraulic fracturing device equal network control system according to claim 4, wherein:

and S01, performing self-test on each master control device, and evaluating the robustness of the master control device, wherein the evaluation parameters comprise computing capacity, storage capacity, working age and working temperature, and the master control device with the robustness lower than a preset value is restricted to be qualified as the master node.

6. The method of controlling a multilevel hydraulic fracturing device equal network control system according to claim 5, wherein: and if the strengths of the rest master control devices are lower than the preset value, selecting the master control device with the highest strength as the master node.

7. The method for controlling a multilevel hydraulic fracturing device equal network control system according to claim 4, wherein: before step S1, the method further includes the step of confirming whether the master node exists in the equal network.

8. The method for controlling a multilevel hydraulic fracturing device equal network control system according to claim 4, wherein: in step S1, the initiating node sends a segment of clock pulse, and the receiving node adjusts its own clock according to the clock pulse to perform synchronization;

and gradually increasing the frequency of the clock pulse until reaching the precision limit of each master control device.

9. The method for controlling a multilevel hydraulic fracturing device equal network control system according to claim 1 or 4, further comprising the steps of:

s6, the main node determines the number of each main control device (5);

s7, the main node performs circumferential indexing of the phase according to the total number of the main control devices (5);

s8, the master node sends the indexing phase angle to each slave node;

s9, the master node and the slave nodes are started in sequence according to the sequence of the phase angles;

s10, issuing the rotating speed and the real-time phase angle by the master node every other time period;

s11, the slave node follows according to the issued rotating speed, and the real-time phase angle is converted into the self following phase angle for closed-loop control;

through the steps, the output pressure fluctuation stability under the equal network control of the multiple electric fracturing devices is realized.

10. The method of controlling a multilevel hydraulic fracturing device equal network control system according to claim 9, wherein: in the working period of the main node, if the auxiliary node is added or quitted, the steps S6-S11 are executed again;

when the master node exits, the process goes to step S1 to reselect the master node.

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