A pipe string and method for rapid resumption of production after well killing in a gas well

Abstract

The present invention provides a pipe string and method for rapid resumption of production after wellbore pressure reduction of a gas well, including an oil pipe, a sleeve, a packer and a plug, wherein the lower end of the oil pipe is connected to the plug, the packer is arranged at the lower part of the oil pipe, and the sleeve is located above the packer and connected to the oil pipe. The present invention has the functions of rapid resumption of production, meeting the needs of later production, simplifying on-site processes, improving construction efficiency, and protecting the production capacity of gas wells. The present invention artificially creates a flow channel with a lower pressure and a smaller diameter than the wellbore by inserting a pipe string for rapid resumption of production once after wellbore pressure reduction of the gas well, which is used to accelerate the upward return flow rate of the gas in the well, improve its liquid carrying capacity, reduce the accumulation of liquid at the bottom of the well, reduce the back pressure at the bottom of the well, and meet the needs of later production. The present invention has the technical advantages of rapid resumption of production and meeting the needs of later production, while simplifying the on-site process and improving the construction efficiency, and plays an extremely important role in protecting the production capacity of gas wells.

Description

Technical Field

[0001] The invention relates to a pipe column and a method for quickly resuming production of a gas well after well killing. Background Art

[0002] For gas wells that cannot be fractured by casing due to graded cementing and need to be modified by tubing layered fracturing tools, it is difficult to pull out the pipe string in the later stage due to the presence of multiple packers and hydraulic anchor tools. This problem can be solved by pulling out the pipe string in time after fracturing is completed and then running a small diameter pipe for production. Pulling the pipe string requires well killing operation. If the blowout is not induced in time after well killing, the bottom layer will be blocked by the killing fluid or the wellbore will accumulate liquid during the replacement blowout stage, causing a large back pressure at the bottom of the well, damaging the reservoir or "killing" the well, which seriously affects the production and life of the gas well. At present, after the well killing and pulling the pipe string, the production pipe is grouting, and then the coiled tubing liquid nitrogen lifting method is used to induce blowout and discharge. The induction and discharge of blowout requires coiled tubing operations and corresponding tools, which are easily restricted by the organization of coiled tubing equipment. In addition, there are many drilling procedures and long cycles after drilling, and the induction and discharge of blowout is not timely, and the recovery effect is not ideal. At the same time, in order to consider the need to run coiled tubing in the later stage, the inner diameter of the production pipe string is limited, which affects the production capacity of the gas well in the later stage. Summary of the invention

[0003] In order to overcome the problem that the on-site well killing after the blowout and drainage requires continuous tubing operation, which is easily restricted by the organization of the continuous tubing equipment, and there are many processes of starting and drilling after the killing, the cycle is long, the on-site recovery effect is not ideal, and the inner diameter of the production string is larger due to the need for the continuous tubing to be lowered, which affects the performance of the gas well capacity, the present invention provides a pipe string and method for rapid recovery of production after the gas well is killed. The present invention artificially creates a flow channel with lower pressure and smaller diameter than the wellbore by lowering a small-diameter recovery production integrated pipe string once after the gas well is killed, which is used to accelerate the gas return flow rate in the well, improve its liquid carrying capacity, reduce the bottom of the well liquid accumulation, reduce the bottom of the well back pressure, and meet the needs of later production at the same time. The present invention has the technical advantages of rapid recovery and meeting the needs of later production, and at the same time simplifies the on-site process, improves the construction efficiency, and plays an extremely important role in protecting the gas well capacity.

[0004] The technical solution adopted by the present invention is:

[0005] A pipe string for rapid resumption of production after well killing in a gas well comprises an oil pipe, a sliding sleeve, a packer and a plug. The lower end of the oil pipe is connected to the plug, the packer is arranged at the lower part of the oil pipe, and the sliding sleeve is located above the packer and connected to the oil pipe.

[0006] The oil pipe is a small-diameter oil pipe, which is an oil pipe with a diameter smaller than the diameter of the original oil pipe in the well.

[0007] The sliding sleeve is an openable sliding sleeve.

[0008] The packer is a compression packer.

[0009] The plugging device is in a closed state when entering the well.

[0010] A method for quickly resuming production after killing a gas well, comprising the following specific steps:

[0011] Step 1: Kill the well and start the layered fracturing string.

[0012] Step 2: Run the tubing string for rapid recovery of production. After the tubing string is in place, set the packer. Open the plug at the lower end of the tubing string to control the flow rate of the tubing. The liquid in the well returns to the wellhead through the plug and is discharged. Open the sliding sleeve to control the flow rate of the tubing. The liquid in the annulus of the casing above the packer returns to the wellhead through the sliding sleeve and is discharged.

[0013] Step three, start well production.

[0014] In the step 2, the pipe string is lowered to the target position so that the liquid in the annulus of the packer can generate a downward pulling force on the pipe string that is not less than the maximum upward force generated by the upward return of gas and liquid in the pipe string.

[0015] In the step 2, the plug at the bottom of the pipe column is opened by injecting gas into the pipe column to pressurize it, and the injected gas is natural gas or liquid nitrogen.

[0016] In the step 2, the plug at the bottom of the pipe string is opened by dropping a tool into the empty wellbore and utilizing the impact force of its fall to open it.

[0017] The beneficial effects of the present invention are:

[0018] The present invention provides a pipe string and method for rapid resumption of production after well killing in a gas well. By running a pipe string for rapid resumption of production once in a gas well after well killing, an artificial liquid flow channel with lower pressure and smaller diameter than the wellbore is provided, thereby accelerating the upward return velocity of gas in the well, improving its liquid carrying capacity, reducing bottom hole liquid accumulation, reducing bottom hole back pressure, and rapidly restoring the gas well production capacity while meeting the needs of later production. The present invention solves the problem that continuous tubing is required for inducing blowout and draining liquid after well killing on site, which is easily restricted by the organization of continuous tubing equipment, and there are many starting and drilling processes after well killing, with a long cycle, and the on-site resumption of production effect is not ideal. The inner diameter of the production pipe string is larger due to the requirement for running the continuous tubing, which affects the performance of the gas well production capacity. The present invention has the technical advantages of rapid resumption of production and meeting the needs of later production, while simplifying the on-site process and improving the construction efficiency, and plays an extremely important role in protecting the gas well production capacity.

[0019] The following is a further description with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a schematic diagram of a pipe string used for rapid resumption of production after well killing in a gas well.

[0021] In the figure, the reference numerals are: 1, oil pipe; 2, sliding sleeve; 3, packer; 4, plugger. DETAILED DESCRIPTION

[0022] Embodiment 1:

[0023] In order to overcome the problem that the on-site well-killing after the blowout is caused by the need for continuous tubing operation, which is easily limited by the organization of the continuous tubing equipment, and there are many procedures for pulling out and drilling after the well is killed, the cycle is long, the on-site recovery effect is not ideal, and the inner diameter of the production string is large due to the need for the continuous tubing to be lowered, which affects the performance of the gas well production capacity, the present invention provides a method as follows Figure 1 The pipe string and method for rapid resumption of production after well killing of a gas well are shown. The present invention artificially creates a flow channel with lower pressure and smaller diameter than the wellbore by inserting a pipe string for rapid resumption of production once after well killing of the gas well, which is used to accelerate the upward return flow rate of the gas in the well, improve its liquid carrying capacity, reduce the accumulation of liquid at the bottom of the well, reduce the back pressure at the bottom of the well, and meet the needs of later production. The present invention has the technical advantages of rapid resumption of production and meeting the needs of later production, while simplifying the on-site process and improving the construction efficiency, which plays an extremely important role in protecting the production capacity of gas wells.

[0024] A pipe string for rapid resumption of production after well pressure reduction of a gas well comprises an oil pipe 1, a sleeve 2, a packer 3 and a plug 4, wherein the lower end of the oil pipe 1 is connected to the plug 4, the packer 3 is arranged at the lower part of the oil pipe 1, and the sleeve 2 is located above the packer 3 and connected to the oil pipe 1.

[0025] The working process of a tubing string device for rapid production resumption after well pressure relief provided by the present invention is as follows: the specific operations after the operation of lowering the tubing string for rapid production resumption are as follows: lowering the tubing string to the target position, the target position is preferably such that the downward pulling force exerted on the tubing string by the liquid in the annulus of the packer 3 is not less than the maximum upward force exerted by the upward return of the gas and liquid in the tubing string; setting the packer 3; injecting gas (natural gas or liquid nitrogen) into the tubing string to pressurize and open the plug 4 at the lower end of the tubing string, timely controlling the oil pipe blowout discharge volume, controlling the oil pipe blowout discharge volume to ensure that the gas in the well has a higher flow rate, and the liquid in the well returns to the wellhead through the plug 4 for discharge; opening the "openable" sliding sleeve 2 by wire operation, timely controlling the oil pipe blowout discharge volume, controlling the oil pipe blowout discharge volume to ensure that the gas in the well has a higher flow rate, and the liquid in the casing annulus above the packer 3 returns to the wellhead for discharge through the "openable" sliding sleeve 2.

[0026] The present invention artificially creates a flow channel with a lower pressure and smaller diameter than the wellbore by inserting a pipe column for rapid production recovery at one time after the gas well is killed, which is used to accelerate the upward return flow rate of the gas in the well, improve its liquid carrying capacity, reduce the bottom of the well liquid accumulation, reduce the bottom of the well back pressure, and meet the needs of later production. The present invention has the technical advantages of rapid production recovery and meeting the needs of later production, while simplifying the on-site process and improving the construction efficiency, which plays an extremely important role in protecting the production capacity of gas wells.

[0027] Embodiment 2:

[0028] Based on Example 1, in this example, the oil pipe 1 is a small-diameter oil pipe, which is an oil pipe with a diameter smaller than the diameter of the original oil pipe in the well.

[0029] The sliding sleeve 2 is an openable sliding sleeve, and the equivalent diameter of the nozzle of the sliding sleeve 2 is relatively small, with the upper limit being that the amount of water discharged from the annulus above the packer 3 is sufficient to be carried to the wellhead by the wellbore gas volume.

[0030] The packer 3 is a compression packer. The packer 3 can be in the following states: fixed tail pipe hanging, lifting or rotating pipe string setting, and lifting or rotating pipe string unsealing.

[0031] The plug 4 is in a closed state when entering the well.

[0032] A method for quickly resuming production after killing a gas well, comprising the following specific steps:

[0033] Step 1: Kill the well and start the layered fracturing string.

[0034] Step 2: Run the pipe string for rapid recovery of production. After the pipe string is put in place, set the packer 3; open the plug 4 at the lower end of the pipe string to control the discharge rate of the tubing, and the liquid in the well returns to the wellhead through the plug; open the sliding sleeve 2 to control the discharge rate of the tubing, and the liquid in the annulus of the casing above the packer 3 returns to the wellhead through the sliding sleeve 2 for discharge;

[0035] Step three, start well production.

[0036] In the step 2, the pipe string is lowered to the target position to seal the annulus liquid with the packer 3, and the downward pulling force on the pipe string is not less than the maximum upward force generated by the upward return of gas and liquid in the pipe string.

[0037] In the step 2, the plug 4 at the bottom of the pipe column is opened by injecting gas into the pipe column to pressurize it, and the injected gas is natural gas or liquid nitrogen.

[0038] In the step 2, the plug 4 at the bottom of the pipe string is opened by dropping a tool into the empty wellbore and utilizing the impact force of its falling to open it.

[0039] The oil pipe 1 in the present invention is a small diameter oil pipe, the diameter of which is smaller than the oil pipe used in the well pressure in step 1, and at the same time, it needs to meet the normal production requirements of carrying liquid in the later stage in step 2.

[0040] like Figure 1 A column according to an embodiment of the present invention is shown. Figure 1It can be seen that the string is composed of (from top to bottom): tubing 1 + "openable" sliding sleeve 2 + packer 3 + plug 4. The tubing 1 is a small diameter tubing. The smaller the diameter, the greater the gas flow rate and the stronger the drainage capacity. The nozzle equivalent diameter of the "openable" sliding sleeve 2 should be smaller, so that the amount of water discharged from the annular space above the packer is enough to be carried to the wellhead by the wellbore gas volume. The packer 3 is a combination of compression type, fixed tail pipe suspension, lifting or rotating string setting, lifting or rotating string unsealing. The plug 4 is in the closed state when it enters the well.

[0041] The operation method of the embodiment of the present invention includes: well pressure, stratified fracturing string; lowering the integrated production string (quick production string); opening the well for production. The specific operation after lowering the integrated production string operation is: lowering the string into place, and the target position is preferably such that the downward pulling force of the liquid in the annulus of the packer on the string is not less than the maximum upward force generated by the gas and liquid in the string; setting the packer 3; injecting gas (natural gas or liquid nitrogen) into the string to pressurize and open the plug 4 at the lower end of the string, and control the oil pipe spraying volume, and control the oil pipe spraying volume to ensure that the gas in the well has a higher flow rate, and the liquid in the well returns to the wellhead through the plug 4 for discharge; open the "openable" sliding sleeve 2 by wire operation, control the oil pipe spraying volume, and control the oil pipe spraying volume to ensure that the gas in the well has a higher flow rate, and the oil casing annulus liquid above the packer 3 returns to the wellhead for discharge through the "openable" sliding sleeve 2.

[0042] Preferably, the plug 4 at the bottom end of the tubular column is opened by dropping a tool into an empty wellbore and applying pressure to open it.

[0043] Preferably, the plug 4 at the bottom end of the pipe string is opened by dropping a tool into an empty wellbore and utilizing the impact force of its falling to open it.

[0044] Preferably, the plug 4 at the bottom end of the pipe string is opened by inserting a tool into the pipe string and injecting gas (natural gas or liquid nitrogen) to pressurize and open it.

[0045] Preferably, the “openable” sliding sleeve 2 is opened by wire operation.

[0046] Preferably, the “openable” sliding sleeve 2 is opened by means of a continuous tubing operation.

[0047] Preferably, the "openable" sliding sleeve 2 is opened by blasting hydraulic action of a pressurized bursting disc in an oil pipe.

[0048] The present invention provides a pipe string and method for rapid resumption of production after well killing in a gas well. After the well is killed in the gas well, a small-diameter production pipe string for resumption of production and drainage is lowered once, thereby artificially providing a liquid flow channel with lower pressure and smaller diameter than the wellbore, accelerating the upward return velocity of the gas in the well, improving its liquid carrying capacity, reducing the accumulation of liquid at the bottom of the well, reducing the back pressure at the bottom of the well, and rapidly restoring the production capacity of the gas well while meeting the needs of later production. The present invention solves the problem that continuous tubing is required for inducing blowout and drainage after well killing on site, which is easily restricted by the organization of continuous tubing equipment, and there are many starting and drilling processes after killing, with a long cycle, and the on-site resumption of production effect is not ideal. The inner diameter of the production pipe string is larger due to the requirement for running the continuous tubing, which affects the production capacity of the gas well. The present invention has the technical advantages of rapid resumption of production and meeting the needs of later production, while simplifying the on-site process and improving the construction efficiency, and plays an extremely important role in protecting the production capacity of the gas well.

[0049] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. Any design that is the same or similar to the present invention belongs to the protection scope of the present invention. The device structure and method technology not described in detail in this embodiment belong to the well-known technology and common method in the industry, and will not be described one by one here.

Claims

1. A method for quickly resuming production of a pipe string after killing a gas well, characterized in that: A pipe string for rapid resumption of production after well killing in a gas well is used, the pipe string comprising an oil pipe (1), a sleeve (2), a packer (3) and a plug (4); the lower end of the oil pipe (1) is connected to the plug (4); the packer (3) is arranged at the lower part of the oil pipe (1); the sleeve (2) is located above the packer (3) and is connected to the oil pipe (1); the oil pipe (1) is a small-diameter oil pipe, which is an oil pipe with a diameter smaller than the diameter of the original oil pipe in the well killing; the sleeve (2) is an openable sleeve; the packer (3) is a compression packer; the plug (4) is in a closed state when entering the well; The specific steps of the rapid production resumption method of the pipe string used for rapid production resumption after gas well killing are as follows: Step 1: Kill the well and start the layered fracturing string. Step 2: Run the tubing string for rapid recovery of production. After the tubing string is in place, set the packer (3); open the plug (4) at the lower end of the tubing string to control the flow rate of the tubing, and the liquid in the well returns to the wellhead through the plug for discharge; open the sliding sleeve (2), control the flow rate of the tubing, and the liquid in the annulus of the casing above the packer (3) returns to the wellhead through the sliding sleeve (2) for discharge; Step three, start well production.

2. The rapid production resumption method of a pipe string for rapid production resumption after well killing of a gas well according to claim 1, characterized in that: In the step 2, the pipe string is lowered to the target position so that the downward pulling force exerted on the pipe string by the liquid in the annulus of the packer (3) is not less than the maximum upward force exerted by the upward return of gas and liquid in the pipe string.

3. The rapid production resumption method of a pipe string for rapid production resumption after well killing of a gas well according to claim 1, characterized in that: In the step 2, the plug (4) at the bottom end of the pipe column is opened by injecting gas into the pipe column to pressurize it, and the injected gas is natural gas or liquid nitrogen.

4. The rapid production resumption method of a pipe string for rapid production resumption after well killing of a gas well according to claim 1, characterized in that: In the step 2, the plug (4) at the bottom end of the pipe string is opened by dropping a tool into the empty wellbore and utilizing the impact force of its fall to open it.

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