Method for injection-production of wellbore sealed by electric packer conveyed by coiled tubing

Abstract

The present invention relates to a method for constructing a continuous oil pipe transmission electric isolation wellbore injection and production method, which is used to run into the wellbore through the continuous oil pipe through the cable to treat different wellbore areas. The pipe string used in the method includes: a first and a second packer, which can be operated to set and unseal to treat different wellbore areas; an electric switch valve, which is arranged between the first and second packers and is used to operate to open and close the fluid communication channel between the pipe and the formation; an isolation valve, which is used to operate to open and close the channel in the pipe; and a fluid control valve, which is used to control the opening and closing of the communication channel between the oil pipe and the formation. The present invention can realize the running of a double-seal cross-isolation pipe string under pressure, the packer can be repeatedly set and unsealed, the squeeze injection or production channel can be opened and closed multiple times, and a single trip of the pipe string can be used to treat multiple sections of the formation.

Description

Technical Field

[0001] The present invention relates to the technical field of downhole operations in the oil and gas industry, and more particularly, to a method for continuous coiled tubing transmission and electric isolation of a wellbore for injection and production. Background Art

[0002] The expandable production packer allows fluid to enter through an inlet channel to expand the packer rubber cylinder. When the setting pressure is reached, the inlet channel is closed to maintain the pressure inside the rubber cylinder and set the packer. When releasing the packer, it depends on the specific mechanical design of the packer. For example, the packer can use a rotary release system to lift and rotate the pipe string to release the rubber cylinder. In contrast, the lift release system requires a certain pulling force to cut the shear pins to release the rubber cylinder.

[0003] The straddle string has an expandable straddle packer to isolate the downhole wellbore, so that injection or production operations can be carried out in this section of the wellbore. This tool requires the following operations on the pipe string, namely, expanding the packer rubber cylinder, locking the pressure inside the rubber cylinder, opening the injection outlet for injection or production construction, closing the injection port, and releasing the packer. When the tool needs to be repeatedly constructed downhole, the tool needs to return to the initial state to be set again. Repeatedly using this tool to set and release downhole has a high risk and great difficulty. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for continuous coiled tubing transmission and electric isolation of a wellbore for injection and production, which can realize the pressure-bearing lowering of a double-packer straddle string. The packer can be repeatedly set and released, and the injection or production channel can be repeatedly opened and closed, and one trip of the pipe string can be used to treat multiple formations.

[0005] The technical solution adopted by the present invention to solve its technical problems is to construct a method for continuous coiled tubing transmission and electric isolation of a wellbore for injection and production, which is used to lower into the wellbore through a coiled tubing with a cable to process different wellbore areas. The pipe string adopted by the method includes:

[0006] The first and second packers, which can be operated to set and release to process different wellbore areas;

[0007] An electric on-off valve, arranged between the first and second packers, for operating to open and close the fluid communication channel between the pipe and the formation;

[0008] An isolation valve, for operating to open and close the pipe internal channel;

[0009] A fluid control valve, for controlling the opening and closing of the communication channel between the inside of the oil pipe and the formation.

[0010] The method includes the following steps:

[0011] First step: Electrically control the isolation valve to cut off the pumping fluid from passing through the bottom channel of the coiled tubing. The packer control valve remains open during the first step.

[0012] Second step: Pump liquid through the coiled tubing string. The liquid enters the liquid inlets of the first and second packers and passes through the control valve liquid inlets to expand and set the packers.

[0013] Third step: Electrically control the packer liquid inlet control valve to keep the packers in the set state. The fluid control valve remains closed in the first three steps.

[0014] Fourth step: Electrically control the fluid control valve to open, allowing the pumped liquid to enter the formation between the two packers through the electric switch valve for formation treatment operations; or allowing the formation fluid to enter the tubing string through the fluid control valve for production.

[0015] Fifth step: After completing the formation treatment or production operations, electrically control the fluid control valve to close, thereby closing the communication channel between the tubing and the formation.

[0016] According to the above solution, the packer control valve is open in the first and second steps to allow the packers to expand and set by liquid inlet. In the third step, after the packers are set, the packer control valve is closed to maintain the expansion pressure of the rubber cylinder and keep the packers in a continuous set state.

[0017] According to the above solution, the tubing string used in the method further includes a first piston disposed in the packer control valve. The liquid inlet of the first piston can be kept in communication with the inside of the pipe. When the piston is open, the liquid inlet is in communication with the packer. The first piston is connected to the electric control system.

[0018] According to the above solution, the packer includes an expandable rubber cylinder, and the rubber cylinder expands by the liquid inlet pressure at the liquid inlet.

[0019] According to the above solution, the tubing string used in the method includes: a second piston disposed in the fluid control valve. The liquid outlet of the second piston can be kept in communication with the inside of the pipe. When the piston is closed, the liquid outlet is isolated from the formation. The second piston is connected to the electric control system.

[0020] Implementing the method of continuous coiled tubing transmission electric packer wellbore injection and production has the following beneficial effects:

[0021] The packer rubber barrel of the present invention has a liquid inlet channel and a control valve that communicate with the fluid inside the pipe. The liquid inlet channel is opened through the control valve. Therefore, the rubber barrel can be filled with liquid to expand and seal the wellbore. The electric switch valve has a liquid outlet channel that communicates the inside of the pipe with the formation, and this channel is controlled by a fluid control valve. After the rubber barrel is fully expanded, the control unit electrically controls the packer control valve to close the connection between the rubber barrel and the liquid inlet channel. Then, the control unit electrically controls the fluid control valve to open the liquid outlet channel of the electric switch valve to communicate with the formation, so that squeezing injection or exploitation can be carried out on the formation area. The present invention can realize the pressure - carrying lowering of a double - packer cross - isolation pipe string. The packer can be set and released repeatedly, and the squeezing injection or exploitation channel can be opened and closed multiple times, enabling a single trip of the pipe string to treat multiple formation sections. Brief Description of the Drawings

[0022] The present invention will be further described below in conjunction with the drawings and embodiments. In the drawings:

[0023] Figure 1 is the state diagram of the packer liquid inlet setting in the method of continuous coiled tubing transmission for electric - sealed wellbore injection and production of the present invention;

[0024] Figure 2 is the state diagram of the packer release in the method of continuous coiled tubing transmission for electric - sealed wellbore injection and production of the present invention;

[0025] Figure 3 is the schematic diagram of the packer release / setting structure in the method of continuous coiled tubing transmission for electric - sealed wellbore injection and production of the present invention;

[0026] Figure 4 is the schematic diagram of the closing / opening structure of the electric switch valve in the method of continuous coiled tubing transmission for electric - sealed wellbore injection and production of the present invention;

[0027] Figure 1 、 2 In figures: 101 - wellbore, 102 - formation, 103 - isolated well section, 104 - continuous coiled tubing, 105 - inner channel of the tubing, 106 - isolation valve, 108 - cross - isolation wellbore injection and production pipe string, 109 - packer, 110 - liquid inlet, 111 - packer control valve, 112 - electric switch valve, 113 - squeezing injection liquid outlet, 114 - fluid control valve, 115 - electric control system unit.

[0028] Figure 3 In figures: 301 - packer, 110 - liquid inlet, 302 - mandrel, 303 - control valve system, 304 - hydraulic chamber, 305 - liquid inlet bypass, 306 - control channel, 307 - first piston, 308 - sealing ring, 309 - packer rubber barrel, 310 - rubber barrel liquid inlet chamber, 311 - spring.

[0029] Figure 4In Chinese: 401 - Electric switch valve, 113 - Extrusion liquid outlet, 114 - Fluid control valve, 402 - Mandrel, 403 - Control valve system, 404 - Hydraulic cavity, 405 - Control channel, 406 - Second piston, 407 - Sealing device, 408 - Sealing ring, 409 - Spring. Detailed implementation mode

[0030] For a clearer understanding of the technical features, objectives, and effects of the present invention, the detailed implementation mode of the present invention will now be described in detail with reference to the accompanying drawings.

[0031] A method for continuously injecting and producing in an electric packer wellbore through coiled tubing is used to process different wellbore areas by lowering coiled tubing through a cable into the wellbore. The string used in the method includes:

[0032] The first and second packers, which can be operated to set and release to process different wellbore areas;

[0033] An electric switch valve, arranged between the first and second packers, for operating to open and close the fluid communication channel between the pipe and the formation;

[0034] An isolation valve, for operating to open and close the internal pipe channel;

[0035] A fluid control valve, for controlling the opening and closing of the communication channel between the inside of the tubing and the formation

[0036] The method includes the following steps:

[0037] In the first step, the isolation valve is electrically controlled to close, cutting off the pumping fluid from passing through the bottom channel of the coiled tubing. The packer control valve remains open during the first step;

[0038] In the second step, the coiled tubing pumps liquid, and the liquid enters the liquid inlets of the first and second packers and passes through the control valve to expand and set the packers;

[0039] In the third step, the packer inlet control valve is electrically controlled to close to keep the packers in the set state. The fluid control valve remains closed during the first three steps;

[0040] In the fourth step, the fluid control valve is electrically controlled to open, enabling the pumped liquid to enter the formation between the two packers through the electric switch valve for formation treatment operations; or enabling the formation fluid to enter the string through the fluid control valve for production;

[0041] In the fifth step, after the formation treatment or production operation is completed, the fluid control valve is electrically controlled to close, thereby closing the communication channel between the tubing and the formation.

[0042] Preferably, the packer control valve is in an open state in the first and second steps, allowing the packer to expand and set by injecting fluid. In the third step, after the packer is set, the packer control valve is in a closed state to maintain the expansion pressure of the rubber cylinder and keep the packer in a continuously set state.

[0043] Preferably, the pipe string used in the method further includes a first piston disposed in the packer control valve. The inlet of the first piston can be kept in communication with the inside of the pipe. When the piston is in an open state, the inlet is in communication with the packer. The first piston is connected to the electric control system. The electric control system can operate to move the first piston to close the inlet in response to an electric control method, causing the packer control valve to be in a closed state.

[0044] Preferably, the packer includes an expandable rubber cylinder, and the rubber cylinder expands by the injection pressure at the inlet.

[0045] Preferably, the pipe string used in the method further includes: a second piston disposed in the fluid control valve. The outlet of the second piston can be kept in communication with the inside of the pipe. When the piston is in a closed state, the outlet is isolated from the formation. The second piston is connected to the electric control system. The electric control system can operate to move the second piston to open the outlet in response to an electric control method, causing the fluid control valve to be in an open state.

[0046] The working principle of the present invention is as follows:

[0047] The cross - interval wellbore injection - production pipe string and the coiled tubing with cable are lowered into the formation together to perform fracturing or other types of injection or production operations. The pipe string has two packers, each packer having an inlet communicating with the tubing, and a packer control valve to open the fluid passage between the packer rubber cylinder and the inlet. Between the two packers, there is an electric switch valve. The outlet of the electric switch valve communicates with the tubing, and the fluid control valve of the electric switch valve controls the opening and closing of the communication passage between the outlet and the formation.

[0048] The control operation unit on the pipe string is coupled to the packer control valve and the fluid control valve. The control unit operates the valve switch according to the electric control instruction.

[0049] During the lowering process, the packer control valve is in an open state and the fluid control valve is in a closed state. Once the pipe string is lowered to the well section to be treated, the isolation valve at the lowest end of the pipe string is closed through an electric control instruction, and then pressure is pumped into the coiled tubing string. The pressure enters the packer rubber cylinder through the open packer control valve to set the packer and seal the well section. The two packers are expandable packers with expandable rubber cylinders, and the rubber cylinders expand with the pressure in the coiled tubing.

[0050] The control unit closes the packer control valve in an electrically controlled manner, closing the communication channel between the packer and the liquid inlet hole, thereby locking the pressure in the expandable rubber barrel of the packer. At the same time, the control unit opens the fluid control valve in an electrically controlled manner to open the fluid channel between the liquid outlet and the wellbore. At this time, the treatment fluid pumped into the pipe string can flow out from the liquid outlet, enter the isolated well section, treat the formation, or the formation fluid can flow out from the liquid outlet for production.

[0051] Finally, the liquid outlet can be closed in an electrically controlled manner, the packer control valve can be opened to release the packer, and the downhole isolation valve can be opened to restore the tubing circulation channel. After the isolation valve is opened, the pipe string can be lowered into a new well section for repeated packing, squeezing, and production.

[0052] Figure 1 Shown is the liquid inlet setting state of the packer 109 in the across-interval wellbore injection-production pipe string 108. The surface fluid pumped through the inner channel 105 of the coiled tubing cannot pass through the closed bottom isolation valve 106. Therefore, the fluid can enter the packer 109 through the packer liquid inlet 110, causing the rubber barrel to expand and set to isolate the well section 103. The packer is designed with a starting setting pressure to prevent premature setting during circulation when lowering. The electrically controlled control system unit 115 in the across-interval pipe string 108 operates the packer control valve 111 of the packer 109, the injection and liquid outlet 113 of the electric switch valve 112, and the opening and closing of the isolation valve 106 through coiled tubing cable electrical control.

[0053] Figure 2 Shown is the across-interval pipe string 108 in the released state after the completion of the across-interval wellbore treatment construction. At this time, the isolation valve 106 is in the open state, the liquid inlet 110 of the packer 109 is in the open state so that the packer can be depressurized and released. In addition, the injection and liquid outlet 113 of the electric switch valve 112 is in the closed state. After the coiled tubing string 104 is released, it can be lowered into other well sections that need to be treated.

[0054] Figure 3 Shown is the released / set structure of the expandable packer. The packer 301 has a control valve system 303 installed on the mandrel 302 with a liquid inlet 110 connected to the coiled tubing 104, and a movable piston 307 is installed in the hydraulic chamber 304 ( Figure 3 Left, the hydraulic chamber is in the closed state, Figure 3Right, hydraulic chamber open state). When the packer 301 starts the pressure injection and setting operation, the liquid inlet 110 is in the open state. The pumped liquid enters the rubber barrel liquid inlet chamber 310 through the liquid inlet 110 to expand and set the packer rubber barrel 309. Then, the hydraulic oil is pumped through the control channel 306 by the electric control system unit 115 to make the piston 307 move upward through the sealing ring 308 after overcoming the resistance of the spring 311 to seal the liquid inlet 110, so as to keep the packer in the set state. After the construction is completed, the electric control system unit 115 is used again to control the piston 307 to open the liquid inlet 110, so that the packer can be depressurized and released.

[0055] Figure 4 The closed / open structure of the electric switch valve is shown. The electric switch valve 401 includes a control valve system 403 installed on the mandrel 402 connected to the coiled tubing 104 and having an extrusion liquid outlet 113. The movable piston 406 is installed in the hydraulic chamber 404 ( Figure 4 Left, hydraulic chamber closed state, Figure 4 Right, hydraulic chamber open state). During the liquid inlet setting operation of the packer, the extrusion liquid outlet 113 of the electric switch valve 401 is in the closed state. When extruding liquid, the hydraulic oil is pumped through the control channel 405 by the electric control system unit 115 to make the piston 406 move downward after overcoming the resistance of the spring 409 to open the extrusion liquid outlet 113 sealed by the sealing device 407 and the sealing ring 408, so as to start the cross-interval extrusion construction. After the construction is completed, the electric control system unit 115 is used again to control the piston 406 to close the extrusion liquid outlet 113.

[0056] The embodiments of the present invention have been described above in conjunction with the accompanying drawings. However, the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the spirit and scope protected by the claims of the present invention. These all fall within the protection scope of the present invention.

Claims

1. A method for injection and production of electric isolation wellbore by coiled tubing transmission, It is characterized in that The method is used to treat different wellbore areas by running a continuous oil pipe through a cable into the wellbore, and the pipe string used in the method includes: two packers, each packer has a liquid inlet connected to the oil pipe, and a packer control valve to open a fluid channel between the packer rubber sleeve and the liquid inlet; an electric switch valve is provided between the two packers, the liquid outlet of the electric switch valve is connected to the oil pipe, and the fluid control valve of the electric switch valve controls the opening and closing of the communication channel between the liquid outlet and the formation; The pipe string used in the method also includes a first piston arranged in the packer control valve, the first piston liquid inlet can be kept in communication with the inside of the pipe, when the first piston is in an open state, the liquid inlet is in a communication state with the packer, and the first piston is connected to a control unit; the pipe string used in the method also includes: a second piston arranged in the fluid control valve, the second piston liquid outlet can be kept in communication with the inside of the pipe, when the second piston is in a closed state, the liquid outlet is in an isolated state with the formation, and the second piston is connected to the control unit; The control unit on the pipe string is coupled to the packer control valve and the fluid control valve; the control unit operates the valve switch according to the electronic control command; Injection methods include: During the lowering process, the packer control valve is in the open state and the fluid control valve is in the closed state; once the tubing string is lowered into the well section to be treated, the isolation valve at the lowest end of the tubing string is closed by an electric control command, and then pressure is pumped into the coiled tubing string, entering the packer rubber cylinder through the opened packer control valve, setting the packer and sealing the well section; the two packers are expandable packers, which have expandable packer rubber cylinders, which expand with the pressure in the coiled tubing; The control unit closes the packer control valve by electric control, closes the communication channel between the packer and the fluid inlet, and locks the pressure in the expansion rubber tube of the packer; at the same time, the control unit opens the fluid control valve by electric control to open the fluid channel between the fluid outlet and the wellbore; at this time, the treatment fluid pumped into the pipe string flows out from the fluid outlet, enters the isolated well section, treats the formation, or the formation fluid flows out from the fluid outlet for production; Finally, the liquid outlet is closed by electric control, the packer control valve is opened to release the packer, and the downhole isolation valve is opened to restore the oil pipe circulation channel; after opening the isolation valve, the tubing can be lowered into a new well section for repeated isolation, squeezing and production.

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