Control method for oil well layering recognition

Abstract

The invention relates to a control method for oil well layering recognition, and belongs to the technical field of oil field oil extraction tools. Controlling the on or off of a switch according to a preset timing layering recognition state time table; in the horizon understanding process, if understanding of the current horizon is completed before understanding action time of the next horizon in the timetable, a horizon-adjusting pulse signal of the corresponding horizon is transmitted by changing pressure of the wellhead at the wellhead, and after the switch monitors the horizon-adjusting pulse signal, the switch in the open state is closed, and the current horizon is understood. The switch corresponding to the position recognition of the next layer in the time table is turned on; and if the recognition action time of the next layer is up and the current layer is still not recognized clearly, a delay pulse signal is transmitted at a wellhead, and after all the switches monitor the delay pulse signal, any switching action is not executed. The scheme is used for solving the problem that the single-layer water exploration period cannot be adjusted in real time according to the production condition of each oil layer in the prior art.

Description

Technical Field

[0001] The invention relates to a control method for oil well stratification recognition, belonging to the technical field of oil field production tools. Background Art

[0002] In the later stage of oil well exploitation, due to the decrease in oil content, water injection is required for oil recovery, which increases the water content of the oil layer. In order to increase production, improve recovery rate and achieve water control and oil stabilization, it is necessary to have a clear understanding of the water content of each oil layer in the oil well. Usually, a mechanical water-finding device is used to find water in each oil layer in layers. The mechanical water-finding device is to lower a multi-stage fixed pipe string into the oil well, and place a slip packer and a water-finding switch in the pipe string. The slip packer is used to block other oil layers to maintain the normal production of a single oil layer. The water content of each layer is judged according to the chemical analysis of the output fluid during normal production of the oil layer, so as to have a clear understanding of the water content of each oil layer.

[0003] The Chinese utility model patent authorization publication document with publication number CN202348249U discloses a downhole stratified oil production control device. The principle of this utility model is to use a packer to isolate each layer in the well, and install a set of intelligent switches on the pipe string corresponding to each target layer. During the water finding and blocking process, the switch can automatically open or close the oil layer according to the set time sequence. Without the need for complicated ground operations, water finding and water blocking measures can be implemented in the oil well, achieving the purpose of arbitrary layer selection for mining and reducing water and increasing oil.

[0004] Although the above-mentioned downhole stratified oil production control device can solve the problem of injection wells finding water in each single layer of the oil well in turn, because the program of the switch during the water finding process has been set and cannot be changed, there is a problem that the single-layer water finding cycle cannot be adjusted in real time according to the production status of each oil layer. Summary of the invention

[0005] The purpose of the present invention is to provide a control method for oil well stratification recognition, so as to solve the problem in the prior art that the single-layer water search cycle cannot be adjusted in real time according to the production status of each oil layer.

[0006] To achieve the above object, the solution of the present invention includes:

[0007] A control method for oil well stratification recognition, which controls the opening or closing of a switch and performs stratum recognition according to a preset switch timing stratification recognition state schedule;

[0008] During the layer recognition process, if the recognition of the current layer is completed before the next layer recognition action time in the schedule, a fixed layer adjustment pulse signal is emitted at the wellhead by changing the wellhead pressure. After the switch detects the layer adjustment pulse signal, the switch in the open state is closed, and the switch corresponding to the next layer recognition in the schedule is opened;

[0009] If the next layer recognition action time in the schedule is reached and the current layer is still not recognized clearly, a delayed pulse signal is emitted at the wellhead by changing the wellhead pressure, and after all switches detect the delayed pulse signal, no switching action is performed;

[0010] The switch is located between two packers respectively used to seal the upper and lower positions of the corresponding oil layers in the casing. The switch executes a timetable and includes a pressure monitoring device for receiving a wellhead pressure signal.

[0011] The present invention controls the recognition process in two forms: preset program and sending pressure pulse signal at the wellhead. Control by preset program means that before the oil well stratification recognition device is lowered, a timed stratification recognition state time table is written in the intelligent switch, and the recognition process recognizes each layer in sequence according to the time table. The control method of sending pressure pulse signal at the wellhead refers to changing the pressure value of the wellhead by manually operating the pressure tanker, and making the change of the pressure value conform to the pre-designed pressure pulse sequence, and the change of the wellhead pressure is transmitted to the well with water as the medium. The pressure pulse sequence is monitored by the pressure monitoring module, and the pressure monitoring module converts the pressure pulse signal into a digital signal and transmits it to the single-chip control module. The single-chip control module transmits the control information to the motor drive module according to the pre-set control rules, thereby controlling the motor drive module to perform corresponding actions, so as to recognize each layer. This method realizes that the oil well stratification recognition layer can be adjusted at any time, and solves the problem that the single-layer water search cycle cannot be adjusted in real time according to the production status of each oil layer because the program of the switch in the stratification recognition process has been set and cannot be changed.

[0012] Furthermore, after the switch detects the layer adjustment pulse signal, the switch corresponding to the layer that has not been recognized determines which layer is the switch corresponding to the next layer recognition according to the recognition action time of each layer in the timetable.

[0013] Through the use of a schedule, the switch can determine whether it is the switch to be turned on at the next level. No external operation is required. The judgment logic is simple and the purpose of layer adjustment can be achieved without additional auxiliary operations.

[0014] Furthermore, after all switches detect the delayed pulse signal, all switches will perform corresponding delayed operations according to the recognized action times in the timetable.

[0015] All switches will perform corresponding delayed operations according to the recognition time in the schedule, so as to facilitate other operations according to the schedule later.

[0016] Furthermore, the layer adjustment pulse signal is generated after the pressure is increased several times within a preset time period, and does not increase pressure within a continuous preset time period after the last pressure increase and pressure relief are completed.

[0017] Furthermore, the delayed pulse signal is a signal that is applied to the pressure several times within a preset time period, and then applied to the pressure again continuously for several minutes within a preset time period after the last application of pressure and pressure relief.

[0018] Furthermore, the several minutes represent a certain time period preset for delay.

[0019] Furthermore, the changing of the pressure at the wellhead is to change the pressure at the wellhead by manually operating a pressure tanker truck at the wellhead.

[0020] The method of changing the pressure at the wellhead by manually operating a pressure tanker truck at the wellhead is simple and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of the oil well stratification recognition device of the present invention;

[0022] Figure 2 It is a schematic diagram of the pressure detection principle structure of the intelligent switch of the present invention;

[0023] Figure 3 It is a pulse control schematic diagram of the layer adjustment control scheme and the delay control scheme of the present invention;

[0024] Figure 4 It is a schematic diagram of the liquid volume and water content monitoring principle structure of the intelligent switch of the present invention;

[0025] In the figure: 1. tubing; 2. pump; 3. screen tube; 4. tail pipe; 5. drop-out string; 511. packer; 521. intelligent switch; 512. packer; 522. intelligent switch; 6. thread plug. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0027] An embodiment of a control method for oil well stratification recognition:

[0028] The embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

[0029] like Figure 1The oil well stratification recognition device of the present invention shown in the figure comprises an oil pipe 1, a pump 2, a screen pipe 3 and a tail pipe 4 which are threadedly connected in sequence; and also comprises a hand-release pipe string 5, which comprises a plurality of water-blocking packers 511, 512 ... 51n and a plurality of intelligent switches 521, 522 ... 52n and a thread plug 6, and each oil layer corresponds to a packer and an intelligent switch. The packer plays a role of isolating each oil layer.

[0030] like Figure 2 The intelligent switch shown is composed of a power module, a pressure monitoring module, a single-chip control module, a motor drive module and a storage module.

[0031] The power module is composed of a high temperature battery pack and a power circuit, and provides a stable power supply for each level of intelligent switches 521, 522...52n.

[0032] The single chip control module processes the pressure signal and sends a control signal to control the action of the motor drive module.

[0033] The pressure monitoring module includes a pressure sensor and a pressure signal acquisition circuit, which is used for real-time monitoring of the pressure signal.

[0034] The motor drive module includes a micro DC motor and a motor control circuit, and receives control signals from the single-chip control module to realize forward and reverse rotation and protection of the motor.

[0035] The storage module is a power-off protection memory that mainly stores information such as pressure and switch action instructions.

[0036] The oil well stratification recognition control principle of the present invention is:

[0037] The recognition process is controlled by two forms: preset program and sending pressure pulse signal at the wellhead. Control by preset program means writing a timed layer recognition status schedule in the intelligent switch before the oil well layer recognition device is lowered. The recognition process recognizes each layer in sequence according to the schedule. The control method of sending pressure pulse signal at the wellhead refers to changing the pressure value at the wellhead by manually operating the pressure tanker, and making the change of pressure value conform to the pre-designed pressure pulse sequence. The change of wellhead pressure is transmitted to the well with water as the medium. The pressure pulse sequence is monitored by the pressure monitoring module, and the pressure monitoring module converts the pressure pulse signal into a digital signal and transmits it to the single-chip control module. The single-chip control module transmits the control information to the motor drive module according to the pre-set control rules, thereby controlling the motor drive module to perform corresponding actions, so as to recognize each layer.

[0038] This embodiment takes three layers as an example, and the specific control method is as follows:

[0039] 1) Before the oil well stratification recognition device is lowered into the formation, the control method is preset. Before the oil well stratification recognition device is lowered into the oil well, the intelligent switch timing stratification recognition state schedule is set. The schedule mainly includes the start delay time, the first layer recognition action time, the second layer recognition action time, and the third layer recognition action time.

[0040] 2) The intelligent switch enters the start-up delay working stage after power is turned on. During this period, the control circuit is in a dormant state and the power consumption is extremely low. At the same time, the oil well stratification recognition device will be lowered into the oil layer during this period.

[0041] 3) After the start-up delay working stage is over, according to the timetable sequence, it will enter the first-layer recognition action time. During this stage, the first-layer intelligent switch 521 is turned on, and the first-layer intelligent switch 522 and the third-layer intelligent switch 523 are turned off. After a period of time, the oil well enters the stable production stage. At this time, the staff takes samples at the wellhead for testing to understand the water content and liquid production of the layer.

[0042] 4) If the first layer can be recognized clearly within the time of the first layer recognition action, the recognition stage of the second layer will be entered according to the preset schedule.

[0043] 5) If the first layer is already known before the second layer is known, the oil well layer recognition device will adopt the layer adjustment control scheme, as follows: Figure 3 As shown, at the wellhead, according to the second layer, the pressure value of the wellhead is changed by manually operating the pressure tanker to transmit a layer adjustment pulse signal, that is, the pressure is increased n times in the time period t1, and the pressure is not increased in the time period t2. After the pressure monitoring module in each layer of the intelligent switch 521, 522...52n in the oil well layer recognition device detects the pulse signal, the switch in the open state is closed, and the switch corresponding to the layer that has not been recognized determines which layer is the switch corresponding to the next layer of layer recognition according to the recognition action time of each layer in the timetable, and the switch corresponding to the layer closest to the current time is turned on. Specifically, the first layer intelligent switch 521 is turned off. If the second layer intelligent switch 522 determines that it is the switch corresponding to the next layer of layer recognition in the timetable, a series of actions are executed, the second layer intelligent switch 522 is turned on, and the third layer intelligent switch 523 is turned off. Then the staff takes samples at the wellhead and enters the second layer recognition stage.

[0044] 6) If the first layer is still not recognized clearly before the second layer recognition action time, then the delay control scheme can be implemented, which is as follows: in advance, the pressure value of the wellhead is changed by manually operating the pressure tanker at the wellhead to send a delayed pulse signal, that is, the pressure is raised n times within the t1 time period, and the pressure is raised again within the t2 time period for m minutes, where m minutes represents the delay time period m, and each layer of the intelligent switch 521,

[0045] After the pressure monitoring module 52b in 522…52n detects the pulse signal, all the intelligent switches will not perform any switching actions to keep the current switching state unchanged, but each layer of the intelligent switches will modify the recognition action time in the timing layered recognition state timetable, and all the intelligent switches will delay the recognition action time of each layer in the timing layered recognition state timetable for m time periods; specifically, after all the intelligent switches have delayed the recognition action time of each layer in the timing layered recognition state timetable for m time periods, the intelligent switch 521 still stays in the first layer recognition stage until the first layer is recognized clearly; the intelligent switches of other layers will then perform related actions according to the current delayed timing layered recognition state timetable and enter the second layer recognition stage.

[0046] 7) Similarly, the oil well stratification recognition intelligent switch executes the timetable sequence in the first and second recognition stages, and the second layer is recognized clearly within the preset time, then the third layer recognition stage is still executed according to the timetable sequence.

[0047] 8) If the third layer recognition stage is advanced or delayed, the control plan will be executed according to step 5 and enter the third layer recognition stage. Eventually, all layers will be clearly recognized and the water search will be completed.

[0048] like Figure 4 As shown, a liquid volume monitoring module and a water content monitoring module can be set underground. The monitoring module imports the monitoring data into the control module for analysis and judgment on whether to terminate the recognition of the current layer in advance or extend the recognition time of the current layer.

Claims

1. A control method for oil well stratification recognition, characterized in that: Control the opening or closing of the switch and perform layer recognition according to the preset switch timing layer recognition status schedule; During the layer recognition process, if the recognition of the current layer is completed before the next layer recognition action time in the schedule, a fixed layer adjustment pulse signal is emitted at the wellhead by changing the wellhead pressure. After the switch detects the layer adjustment pulse signal, the switch in the open state is closed, and the switch corresponding to the next layer recognition in the schedule is opened; If the next layer recognition action time in the schedule is reached and the current layer is still not recognized clearly, a delayed pulse signal is emitted at the wellhead by changing the wellhead pressure, and after all switches detect the delayed pulse signal, no switching action is performed; The switch is located between two packers respectively used to seal the upper and lower positions of the corresponding oil layers in the casing. The switch executes a timetable and includes a pressure monitoring device for receiving a wellhead pressure signal.

2. The control method for oil well stratification recognition according to claim 1, characterized in that: After the switch detects the layer adjustment pulse signal, the switch corresponding to the layer that has not been recognized determines which layer is the switch corresponding to the next layer recognition according to the recognition action time of each layer in the timetable.

3. The control method for oil well stratification recognition according to claim 1, characterized in that: After all switches detect the delayed pulse signal, all switches will perform corresponding delayed operations according to the recognized action time in the schedule.

4. The control method for oil well stratification recognition according to claim 1, characterized in that: The layer adjustment pulse signal is generated after the pressure is increased several times within a preset time period, and the pressure is not increased again within a continuous preset time period after the last pressure increase and pressure relief are completed.

5. The control method for oil well stratification recognition according to claim 1, characterized in that: The delayed pulse signal is generated after the pressure is increased several times within a preset time period, and the pressure is increased again continuously for several minutes within a continuous preset time period after the pressure is increased and the pressure is released for the last time.

6. The control method for oil well stratification recognition according to claim 5, characterized in that: The several minutes represent a certain time period preset for delay.

7. The control method for oil well stratification recognition according to claim 1, characterized in that: The changing of the pressure at the wellhead is to change the pressure at the wellhead by manually operating a pressure tanker at the wellhead.

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