Offshore deep continuous foam liquid drainage gas production process pipe column and operation method

Abstract

The invention discloses an offshore deep continuous foam liquid drainage gas production process pipe column and an operation method, the pipe column comprises a production sleeve, an oil pipe, a lower suspension packer, an upper suspension packer and a continuous oil pipe, a production packer and a top packer are sequentially arranged between the oil pipe and the production sleeve from top to bottom, the oil pipe is located above the production packer for punching, and the continuous oil pipe is located above the production packer for drilling. The lower suspension packer is arranged below the punching position, the upper suspension packer is arranged above the punching position, the upper suspension packer is connected with the lower suspension packer in a sealed mode through an inserting head, and the lower portion of the lower suspension packer is connected with the coiled tubing. A foam scrubbing agent channel from an oil pipe and sleeve annulus to an oil pipe and continuous oil pipe annulus is established through cooperation of multiple tools, the foam scrubbing agent is introduced into a deep shaft liquid accumulation well section below a production packer and above a production layer from the oil pipe and production sleeve annulus, and the fluid density of a shaft is reduced; the mixed fluid is discharged from the continuous oil pipe and the upper oil pipe, and continuous and stable discharging and mining of the gas well are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of continuous stable production of offshore gas wells, and particularly relates to a deep continuous foam liquid drainage gas production process string and operation method for offshore wells. BACKGROUND

[0002] All gas wells of offshore oil and gas fields have production packers, and the oil casing annulus is not connected; the upper part of the production string has a downhole safety valve; more than 90% of the gas wells are high-deviation wells, and the well deviation and dogleg are large, so the conventional operation is limited to a certain extent. For the gas wells with a long distance between the production packer and the production layer, the conventional gas lifting can only drain the liquid above the production packer, and cannot drain the deep liquid below the production packer. For offshore gas wells, the foam drainage agent can only be injected from the wellhead tubing into the well section below the production packer, and cannot be injected from the oil casing annulus to the deep well section, so it cannot be continuously produced. Therefore, a deep continuous foam liquid drainage gas production process suitable for offshore gas wells is urgently needed to realize continuous stable and efficient drainage and production of offshore gas wells and improve the development efficiency of gas fields. SUMMARY

[0003] In view of the existing technical problems, the present application provides a deep continuous foam liquid drainage gas production process string and operation method for offshore wells, which aims to overcome the problems in the above-mentioned technology.

[0004] To achieve the above-mentioned purpose, the present application provides the following technical scheme: A deep continuous foam liquid drainage gas production process string for offshore wells, comprising a production casing, a tubing, a lower hanging packer, an upper hanging packer and a coiled tubing, wherein the production casing and the tubing are sequentially provided with a production packer and a top packer from top to bottom, the tubing is perforated above the production packer, the lower hanging packer is arranged below the perforation, the upper hanging packer is arranged above the perforation, the upper hanging packer is sealingly connected with the lower hanging packer through an insertion head, and the lower hanging packer is connected with the coiled tubing below.

[0005] Optionally, the body of the lower hanging packer is provided with a one-way valve, which allows the annular fluid of the production casing and the tubing to flow downward and prevents the formation produced fluid from flowing upward.

[0006] Optionally, the upper end of the lower hanging packer is provided with a sealing cylinder, and the lower part of the upper hanging packer is provided with an insertion head, which is inserted into the upper end sealing cylinder of the lower hanging packer.

[0007] Optionally, the liquid drainage gas production process string is suitable for offshore liquid accumulation gas wells with an oil content of less than 20%, a water production of less than 50 m3, a formation pressure coefficient of greater than or equal to 0.2, and a bottom hole temperature of less than or equal to 180 DEG C.

[0008] Optionally, the end of the coiled tubing is within 50 meters of the top of the production zone below the top packer.

[0009] A method for operating the offshore deep foam liquid drainage gas production process string of any of the preceding, comprising the steps of: Step one, lower the special lower hanging packer: the operating coiled tubing is connected with battery, electric setting tool, lower hanging packer and coiled tubing in sequence; the lower hanging packer is lowered to the position above the production packer by the operating coiled tubing; the electric setting tool is set by the battery; then the operating coiled tubing is separated from the lower hanging packer through the electric setting tool; the operating coiled tubing, battery and electric setting tool are pulled out. Step two, lower the perforating tool to perforate: the operating coiled tubing is connected with battery and perforating tool in sequence; the perforating tool is lowered to the upper end of the lower hanging packer; the depth is calibrated by the lower hanging packer as the positioning tool; the perforating tool is driven by the battery to perforate the tubing; the operating coiled tubing, battery and perforating tool are pulled out. Step three, lower the upper hanging packer: the operating coiled tubing is connected with battery, electric setting tool and upper hanging packer in sequence; the insertion head of the upper hanging packer is inserted into the sealing cylinder at the upper end of the lower hanging packer; the upper hanging packer is set above the perforated position of the tubing by the electric setting tool driven by the battery; then the operating coiled tubing is separated from the upper hanging packer through the electric setting tool; the operating coiled tubing, battery and electric setting tool are pulled out.

[0010] In summary, the technical effects and advantages of the present application are as follows: for the offshore liquid accumulation gas well with oil content less than 20%, water production less than 50 cubic meters, formation pressure coefficient greater than or equal to 0.2 and bottom hole temperature less than or equal to 180℃, the present application establishes a foam drainage agent channel from the tubing and casing annulus to the tubing and coiled tubing annulus by cooperating with multiple tools, introduces the foam drainage agent from the tubing and production casing annulus to the deep wellbore liquid accumulation well section below the production packer and above the production zone, fully mixes the injected foam drainage agent with the deep wellbore fluid, reduces the density of the mixed fluid, and discharges the mixed fluid from the coiled tubing and the upper tubing, thereby realizing continuous and stable drainage and production of the gas well. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort.

[0012] Figure 1 It is an embodiment of the present application that the offshore deep foam liquid drainage gas production process string is shown in the figure; Figure 2 This is a schematic diagram of the first operation in one embodiment of the present invention; Figure 3 This is a schematic diagram of the second operation in one embodiment of the present invention; Figure 4 This is a schematic diagram of the third operation in one embodiment of the present invention.

[0013] Among them, 1. casing; 2. downhole safety valve; 3. tubing; 4. upper suspended packer; 5. lower suspended packer; 6. production packer; 7. coiled tubing; 8. top packer; 9. positioning insert seal; 10. screen pipe; 11. working coiled tubing; 12. battery; 13. electric setting tool; 14. drilling tool. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0016] This embodiment proposes a continuous foam drainage gas production process string for deep-sea environments, such as... Figures 1-4 As shown, its tubing mainly includes a lower suspended packer 5, an upper suspended packer 4, a coiled tubing 7, and a positioning insertion seal 9.

[0017] The original production well string includes: production casing 1 and tubing 3. A production packer 6 and a top packer 8 are installed from top to bottom in the annular space between the tubing 3 and the production casing 1. The lower end of the tubing 3 passes through the top packer 8 and extends to the gas well production layer. The tubing 3 is connected to a positioning insertion seal 9. The positioning insertion seal 9 is inserted into the rubber sleeve of the top packer 8 to achieve sealing of the upper and lower annular spaces of the top packer 8.

[0018] The lower suspended packer 5 is set at a suitable position on the upper tubing 3 of the production packer 6. The lower suspended packer 5 is connected to a continuous tubing 7. The end of the continuous tubing 7 is within 50 meters of the top of the production layer below the top packer 8. The lower suspended packer 5 is equipped with a check valve to allow the annular fluid in the production casing and tubing to flow downwards and to prevent the formation production fluid from flowing upwards.

[0019] The upper end of the lower hanging packer 5 is provided with a sealing cylinder, and the body is provided with a single flow channel; the oil pipe 3 at a suitable position is perforated; the upper hanging packer 4 is set above the perforated position of the oil pipe 3, and the lower part of the upper hanging packer 4 is provided with an insertion head which is inserted into the upper end sealing cylinder of the lower hanging packer 5.

[0020] In the embodiment, the single flow valve, the lower hanging packer, the sealing cylinder, the insertion head and the upper hanging packer form a seal, effectively maintaining the wellbore integrity during the operation process and the production process.

[0021] Specifically, the single flow valve of the body of the lower hanging packer 5 cooperates with the perforation of the oil pipe 3, and a flow channel is established through the oil pipe 3 and the annulus of the continuous oil pipe 7 below the lower hanging packer 5, so that the foam agent is introduced from the annulus of the oil pipe 3 and the production casing 1 to the deep wellbore fluid well section above the production zone below the production packer 6, the injected foam agent is fully mixed with the deep wellbore fluid, the wellbore fluid pressure density is reduced, and the mixed fluid is discharged through the continuous oil pipe 7 and the upper oil pipe 3, so as to realize continuous and stable production of the gas well.

[0022] In the embodiment, the lower hanging packer 5 and the upper hanging packer 4 are in a split structure and are not an integral whole. The lower hanging packer 5 is used to position the perforated position of the oil pipe 3, and an anchor is not needed to position the perforated position. The upper end of the lower hanging packer 5 is provided with a sealing cylinder, and the insertion head of the upper hanging packer 4 is inserted into the lower hanging packer 5, so as to realize the sealed connection of the insertion head and the sealing cylinder. The body of the lower hanging packer 5 is provided with a single flow valve, which allows the annulus fluid of the production casing 1 and the oil pipe 3 to flow downward and prevents the formation produced fluid from flowing upward.

[0023] The drainage gas recovery process string of the embodiment is suitable for offshore fluid accumulation gas wells with an oil content of less than 20%, a water production of less than 50 m3, a formation pressure coefficient of greater than or equal to 0.2, and a bottom hole temperature of less than or equal to 180℃. Through the non-moving string modification, continuous and stable and efficient production of the gas well is realized, and technical support is provided for the drainage gas recovery of the fluid accumulation gas well.

[0024] The embodiment further provides an operation method of the offshore deep continuous foam drainage gas recovery process, which comprises lowering a lower hanging packer, perforating a lower perforating tool, and lowering an upper hanging packer, and specifically comprises the following steps. Step one, lowering the lower hanging packer: the operation continuous oil pipe 11 is connected with a battery 12, an electric setting tool 13, the lower hanging packer 5 and the continuous oil pipe 7 in sequence. The lower hanging packer 5 is lowered above the oil pipe 3 at a suitable position by using the operation continuous oil pipe 11, the battery 12 drives the electric setting tool 13 to set the lower hanging packer 5, then the operation continuous oil pipe 11 is separated from the lower hanging packer 5 through the electric setting tool 13, and the operation continuous oil pipe 11, the battery 12 and the electric setting tool 13 are pulled out.

[0025] Step two, the lower perforating tool is perforated: the workover coiled tubing 11 is connected with the battery 12 and the perforating tool 14 in turn, the perforating tool 14 is lowered to the upper end of the lower hanging packer 5, the lower hanging packer 5 is used as a depth calibration tool, the battery 12 is used to drive the perforating tool 14 to perforate the oil pipe 3, and then the workover coiled tubing 11, the battery 12 and the perforating tool 14 are pulled out.

[0026] Step three, the upper hanging packer is lowered: the workover coiled tubing 11 is connected with the battery 12, the electric setting tool 13 and the upper hanging packer 4 in turn, the insertion head of the upper hanging packer 4 is inserted into the sealing cylinder at the upper end of the lower hanging packer 5, the battery 12 is used to drive the electric setting tool 13 to set the upper hanging packer 4 above the perforated position of the oil pipe 3, and then the workover coiled tubing 11 is separated from the upper hanging packer through the electric setting tool 13, and the workover coiled tubing 11, the battery 12 and the electric setting tool 13 are pulled out.

[0027] For the old well with liquid accumulation, according to the depth of the wellbore liquid accumulation and the wellhead pressure and yield required during continuous production, the annular foam agent dosage is optimized, the perforation position, coiled tubing length, lower hanging packer position and wellhead injection pressure are optimized and designed, the deep liquid accumulation in the wellbore is discharged, continuous and stable efficient liquid discharge and gas production are realized, and the gas well recovery is improved.

[0028] In summary, the embodiment is aimed at the offshore liquid accumulation gas well with an oil content less than 20%, a water production less than 50 m3, a formation pressure coefficient greater than or equal to 0.2 and a bottom hole temperature less than or equal to 180℃. The foam agent channel is established from the annulus between the oil pipe and the production casing to the annulus between the oil pipe and the coiled tubing by cooperating with multiple tools, the foam agent is introduced from the annulus between the oil pipe and the production casing to the deep wellbore liquid accumulation section above the production packer, the injected foam agent is fully mixed with the deep fluid in the wellbore, the mixed fluid is discharged from the coiled tubing and the upper oil pipe, and continuous and stable drainage and production of the gas well are realized.

[0029] Although the preferred embodiment of the present application is described above in combination with the drawings, the present application is not limited to the above specific embodiments, and the above specific embodiments are only illustrative and not limiting, and those skilled in the art can make many specific changes under the guidance of the present application without departing from the purpose of the present application and the scope protected by the claims, which are all within the protection scope of the present application.

Claims

1. A marine deep continuous foam drainage gas production process string, characterized in that, The production string, the tubing, the lower hanging packer, the upper hanging packer and the coiled tubing are included, the production packer and the top packer are sequentially arranged from top to bottom between the tubing and the production string, the tubing is perforated above the production packer, the lower hanging packer is arranged below the perforation, the upper hanging packer is arranged above the perforation, the upper hanging packer is sealingly connected with the lower hanging packer through the insertion head, and the coiled tubing is connected below the lower hanging packer.

2. The offshore deep-foam drainage gas-recovery process string of claim 1, wherein, The body of the lower hanging packer is provided with a one-way valve, which allows the annulus fluid of the production string and the tubing to flow downward and prevents the formation production fluid from flowing upward.

3. The offshore deep-foam drainage gas-recovery process string of claim 1, wherein, The upper end of the lower hanging packer is provided with a sealing cylinder, and the lower part of the upper hanging packer is provided with an insertion head which is inserted into the upper end sealing cylinder of the lower hanging packer.

4. The offshore deep-foam dewatering gas production process string of claim 1, wherein, The drainage gas recovery process string is suitable for offshore liquid accumulation gas wells with an oil content of less than 20%, a water production of less than 50 m3, a formation pressure coefficient of greater than or equal to 0.2, and a bottom hole temperature of less than or equal to 180 DEG C.

5. The offshore deep-foam dewatering gas production process string of claim 1, wherein, The end of the coiled tubing is within 50 meters from the top of the production layer below the top packer.

6. A method of operating a marine deep continuous foam drainage gas production process string according to any one of claims 1 to 5, characterised in that, The method comprises the following steps: Step one, lower the lower hanging packer: the working coiled tubing is sequentially connected with the battery, the electric setting tool, the lower hanging packer and the coiled tubing, the lower hanging packer is lowered into the tubing above the production packer by using the working coiled tubing, the battery drives the electric setting tool to set the lower hanging packer, then the working coiled tubing is separated from the lower hanging packer through the electric setting tool, and the working coiled tubing, the battery and the electric setting tool are pulled out; Step two, lower the perforating tool to perforate: the working coiled tubing is sequentially connected with the battery and the perforating tool, the perforating tool is lowered to the upper end of the lower hanging packer, the depth is calibrated by using the lower hanging packer as the positioning tool, the battery drives the perforating tool to perforate the tubing, and the working coiled tubing, the battery and the perforating tool are pulled out; Step three, lower the upper hanging packer: the working coiled tubing is sequentially connected with the battery, the electric setting tool and the upper hanging packer, the insertion head of the upper hanging packer is inserted into the sealing cylinder at the upper end of the lower hanging packer, the battery drives the electric setting tool to set the upper hanging packer above the perforation position of the tubing, then the working coiled tubing is separated from the upper hanging packer through the electric setting tool, and the working coiled tubing, the battery and the electric setting tool are pulled out.

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