Downhole pressurized gas well drainage process pipe column and method

Abstract

The invention discloses an underground pressurized gas well discharge and recovery process pipe column which comprises an outer layer pipe column, a first inner layer pipe column and a second inner layer pipe column, the outer layer pipe column extends into a sleeve, and an outer pipe supporting packer is arranged on the outer side of the lower end of the outer layer pipe column; the upper end of the first inner-layer tubular column is sealed in the outer-layer tubular column, and the lower end of the first inner-layer tubular column extends out of the outer-layer tubular column; the second inner-layer tubular column is arranged in the outer-layer tubular column, the second inner-layer tubular column is arranged above the first inner-layer tubular column, and a gas compressor is arranged on the second inner-layer tubular column. According to the underground pressurization gas well drainage and recovery process pipe column, the purpose of lifting accumulated liquid at the bottom of a gas well to the ground can be achieved, and the effect of draining the accumulated liquid in a shaft of the gas well is achieved; the well bottom flowing pressure of the gas well can be further reduced, the production pressure difference is increased, and the purpose of improving the overall gas well recovery efficiency is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of offshore oilfield drainage and gas production, and in particular to a downhole pressurized gas well drainage and production process pipe string and method. Background Art

[0002] Due to long-term exploitation of some gas wells in onshore and offshore oil fields, the formation gas pressure will gradually decrease with the increase in production. After the formation gas pressure decreases, the gas lift flow rate will gradually decrease compared with the previous exploitation. When the flow rate drops to a certain level, the produced gas is not enough to lift the associated liquid in the gas production process to the ground, resulting in accumulation of formation liquid in the gas lift string. The liquid accumulation pressure further leads to a decrease in the output gas volume, and the gas flow rate further decreases, which makes the liquid accumulation problem more serious. When the liquid accumulation reaches a certain level, it will completely block the gas production channel, seriously affecting the production of the gas well.

[0003] Therefore, in order to ensure the normal exploitation of gas wells and improve the recovery efficiency, it is urgent to propose an underground pressurized gas well drainage and production process string to effectively solve the problem of liquid accumulation in the gas production channel caused by insufficient energy of the gas well. Summary of the invention

[0004] The present application aims to solve the problem of liquid accumulation in the wellbore in the late stage of gas well exploitation. In combination with the characteristics of offshore oil field gas production pipe strings, an underground pressurized gas well drainage process pipe string and method are invented to solve the problem of gas production decline and low recovery rate caused by liquid accumulation in the wellbore in the late stage of gas well exploitation. A new drainage gas production process pipe string and method are provided for gas well development to improve the recovery rate of gas fields.

[0005] To achieve the above objectives, this application provides the following technical solutions:

[0006] A downhole pressurized gas well drainage and production process string, comprising:

[0007] An outer tubular column, the outer tubular column extends into the casing, and an outer side of the lower end of the outer tubular column is provided with an external tubular support packer;

[0008] A first inner tube string, wherein the upper end of the first inner tube string is sealed inside the outer tube string, and the lower end of the first inner tube string extends out of the outer tube string;

[0009] The second inner tubular string is arranged inside the outer tubular string, the second inner tubular string is arranged above the first inner tubular string, and a gas compressor is arranged on the second inner tubular string.

[0010] Furthermore, a downhole safety valve is provided on the outer tubular string, and the first inner tubular string is located below the downhole safety valve.

[0011] Furthermore, the second inner tubular string is located above the downhole safety valve.

[0012] Furthermore, the upper end of the first inner tubular string is connected to the outer tubular string via an in-pipe hanging packer.

[0013] Furthermore, the upper end of the outer tubing string is hung in the casing through an outer tubing hanger.

[0014] Furthermore, the upper end of the second inner tubular string is hung in the outer tubular string through an inner tubing hanger.

[0015] A method for the aforementioned downhole pressurized gas well drainage process string comprises the following steps:

[0016] The outer tubing string is suspended by an outer tubing hanger and connected to a downhole safety valve. Before lowering the downhole safety valve, the hydraulic control pipeline is first connected to the downhole safety valve. The hydraulic control pipeline is lowered together with the downhole safety valve. The lower part of the outer tubing string is connected to the external support packer. After the external support packer is lowered to the target depth, the external support packer is set and sealed, and the stratification is achieved by using the external support packer.

[0017] When the formation pressure is sufficient, the gas below the outer support packer enters from the bottom of the outer tubing string and sprays to the wellhead;

[0018] When the formation pressure is insufficient and the bottom of the well is accumulated with liquid, the first inner string is lowered into the outer string, the first inner string is first connected to the inner pipe hanging packer, lowered to a predetermined depth, the inner pipe hanging packer is set below the downhole safety valve in the outer string, and then the string above the inner pipe hanging packer is pulled out, and the second inner string is lowered, the bottom of the second inner string is connected to a gas compressor, and the top of the second inner string is connected to an inner layer tubing hanger;

[0019] The gas compressor is powered by cables, and the gas and liquid produced from the first inner layer pipe string are sucked into the gas compressor, and then lifted to the ground after being pressurized, thereby playing the role of draining liquid and recovering gas.

[0020] In summary, the technical effects and advantages of the present invention are as follows: the downhole pressurized gas well production process tubing of the present invention can achieve the purpose of lifting the accumulated liquid at the bottom of the gas well to the ground, and has the function of discharging the accumulated liquid in the wellbore of the corresponding gas well; it can further reduce the bottom flow pressure of the gas well and increase the production pressure difference, thereby achieving the purpose of improving the overall gas well recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 It is a schematic diagram of the structure of a downhole pressurized gas well production process string in one embodiment of the present invention.

[0023] Among them: 1. Outer tubing hanger; 2. Inner tubing hanger; 3. Gas compressor; 4. Casing; 5. Downhole safety valve; 6. Outer tubing string; 7. First inner tubing string; A. Hydraulic control pipeline; B. Electric cable; C. Inner-tube hanging packer; D. Outer-tube supporting packer. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In addition, 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.

[0026] This embodiment provides a downhole pressurized gas well drainage process string, such as Figure 1 As shown, it includes an outer tubular string 6, a first inner tubular string 7 and a second inner tubular string. The outer tubular string 6 extends into the casing 4, and an outer support packer D is provided on the outer side of the lower end of the outer tubular string 6; the outer support packer D is a gas well stratification tool, which plays the role of stratum stratification, supporting the bottom weight of the outer tubular string 6 and straightening. The upper end of the first inner tubular string 7 is sealed inside the outer tubular string 6, and the lower end of the first inner tubular string 7 extends out of the outer tubular string 6; the second inner tubular string is arranged inside the outer tubular string 6, and the second inner tubular string is arranged above the first inner tubular string 7. The second inner tubular string is used to install a gas compressor 3, and a gas compressor 3 is provided on the second inner tubular string. The first inner tubular string 7 can increase the lifting velocity of the produced gas and lift the bottom gas and liquid to the suction port of the gas compressor 3. The gas compressor 3 is used to lift the first inner layer pipe string 7 to the vicinity of the gas compressor 3 , and the gas and liquid are sucked into the gas compressor 3 , pressurized in the gas compressor 3 , and the gas and liquid are ejected at high speed through the outlet and lifted to the ground.

[0027] When the formation pressure is sufficient, the outer tubing string 6 is the gas production channel; when the formation pressure is insufficient, resulting in liquid accumulation at the bottom of the well and the production decreases, the first inner tubing string 7 and the second inner tubing string are installed in the outer tubing string 6, and the gas compressor 3 is pressurized, and the accumulated liquid flows to the ground through the first inner tubing string 7, the outer tubing string 6 and the second inner tubing string.

[0028] Furthermore, the outer tubular string 6 is provided with a downhole safety valve 5, and the first inner tubular string 7 is located below the downhole safety valve 5. The downhole safety valve 5 is a tubular string well control tool, which can close the gas production channel of the outer tubular string 6 in an emergency to ensure well control safety.

[0029] Furthermore, the second inner pipe string is located above the downhole safety valve 5 .

[0030] Furthermore, the upper end of the first inner layer tubular string 7 is connected to the outer layer tubular string 6 via an in-tube hanging packer C. The in-tube hanging packer C is used to hang the first inner layer tubular string 7 .

[0031] Specifically, the upper end of the outer tubing string 6 is hung in the casing 4 through the outer tubing hanger 1 , and the outer tubing hanger 1 is used to hang the outer tubing string 6 .

[0032] Furthermore, the upper end of the second inner tubular string is suspended in the outer tubular string 6 through the inner tubular hanger 2. The inner tubular hanger 2 is used to hang the second inner tubular string and the gas compressor 3.

[0033] A method for the aforementioned downhole pressurized gas well drainage process string comprises the following steps:

[0034] 1) Lowering the outer pipe string 6;

[0035] 2) The external support packer D is set;

[0036] 3) Run the first inner string, set the packer hanging outside the pipe, and run the second inner string;

[0037] 4) Start the gas compressor 3 to lift.

[0038] Specifically:

[0039] The outer tubing string 6 is suspended by the outer tubing hanger 1 and connected to a downhole safety valve 5. Before lowering the downhole safety valve 5, the hydraulic control pipeline A is first connected to the downhole safety valve 5. The hydraulic control pipeline A is lowered together with the downhole safety valve 5. The lower part of the outer tubing string 6 is connected to the outer tube support packer D. After the outer tube support packer D is lowered to the target depth, the outer tube support packer D is set and sealed, and the outer tube support packer D is used to achieve stratification;

[0040] When the formation pressure is sufficient, the gas below the outer support packer D enters from the bottom of the outer pipe string 6 and sprays to the wellhead;

[0041] When the formation pressure is insufficient and the bottom of the well is accumulated with liquid, the first inner layer tubular string 7 is lowered into the outer layer tubular string 6, and the first inner layer tubular string 7 is first connected to the inner pipe hanging packer C, lowered to a predetermined depth, and the inner pipe hanging packer C is set below the downhole safety valve 5 in the outer layer tubular string 6, and then the hand is removed, and the tubular string above the inner pipe hanging packer C is pulled out, and then the second inner layer tubular string is lowered, and the bottom of the second inner layer tubular string is connected to the gas compressor 3, and the top of the second inner layer tubular string is connected to the inner layer oil pipe hanger 2;

[0042] The gas compressor 3 is powered by a cable, and the gas and liquid produced from the first inner layer pipe string 7 are sucked into the gas compressor 3, and are lifted to the ground after being pressurized, thereby playing the role of draining liquid and recovering gas.

[0043] In summary, the downhole pressurized gas well production process tubing of the present embodiment can achieve the purpose of lifting the liquid accumulated at the bottom of the gas well to the ground, and has the function of discharging the liquid accumulated in the wellbore of the gas well; it can further reduce the bottomhole flow pressure of the gas well and increase the production pressure difference, thereby achieving the purpose of improving the overall gas well recovery rate.

[0044] For ease of description, spatially relative terms such as "upper", "lower", "outer layer", "inner layer" and the like are used in the embodiments to illustrate the relationship of one element or feature shown in the figures relative to another element or feature. It should be understood that in addition to the orientation shown in the figures, the spatial terms are intended to include different orientations of the device in use or operation. Therefore, the exemplary term "lower" can include both upper and lower orientations.

[0045] Furthermore, relational terms such as "3" and "4" etc. are merely used to distinguish one component from another having the same name, but do not necessarily require or imply any such actual relationship or order between these components.

[0046] Although the preferred implementation cases of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms of specific changes without departing from the scope of protection of the invention spirit and claims, which all fall within the scope of protection of the present invention.

Claims

1. A downhole pressurized gas well drainage and production process string, characterized in that: include: An outer tubular column, the outer tubular column extends into the casing, and an outer side of the lower end of the outer tubular column is provided with an external tubular support packer; A first inner tube string, wherein the upper end of the first inner tube string is sealed inside the outer tube string, and the lower end of the first inner tube string extends out of the outer tube string; The second inner tubular string is arranged inside the outer tubular string, the second inner tubular string is arranged above the first inner tubular string, and a gas compressor is arranged on the second inner tubular string.

2. A downhole pressurized gas well drainage and production process string according to claim 1, characterized in that: The outer tubular string is provided with a downhole safety valve, and the first inner tubular string is located below the downhole safety valve.

3. A downhole pressurized gas well drainage and production process string according to claim 2, characterized in that: The second inner tubular string is located above the downhole safety valve.

4. A downhole pressurized gas well drainage and production process string according to claim 1, characterized in that: The upper end of the first inner layer tubular string is connected to the outer layer tubular string via an in-pipe hanging packer.

5. The downhole pressurized gas well drainage and production process string according to claim 1, characterized in that: The upper end of the outer tubing string is hung in the casing through an outer tubing hanger.

6. A downhole pressurized gas well drainage and production process string according to claim 1, characterized in that: The upper end of the second inner tubular string is suspended in the outer tubular string through an inner tubing hanger.

7. A method for the downhole pressurized gas well drainage process string according to any one of claims 1 to 6, characterized in that: The following steps are involved: The outer tubing string is suspended by an outer tubing hanger and connected to a downhole safety valve. Before lowering the downhole safety valve, the hydraulic control pipeline is first connected to the downhole safety valve. The hydraulic control pipeline is lowered together with the downhole safety valve. The lower part of the outer tubing string is connected to the external support packer. After the external support packer is lowered to the target depth, the external support packer is set and sealed, and the stratification is achieved by using the external support packer. When the formation pressure is sufficient, the gas below the outer support packer enters from the bottom of the outer tubing string and sprays to the wellhead; When the formation pressure is insufficient and the bottom of the well is accumulated with liquid, the first inner layer tubing string is lowered into the outer layer tubing string, the first inner layer tubing string is first connected to the inner pipe hanging packer, lowered into a predetermined depth, the inner pipe hanging packer is set and sealed at a position below the downhole safety valve in the outer layer tubing string, and then the tubing string above the inner pipe hanging packer is pulled out, and the second inner layer tubing string is lowered, the bottom of the second inner layer tubing string is connected to a gas compressor, and the top of the second inner layer tubing string is connected to an inner layer tubing hanger; The gas compressor is powered by cables, and the gas and liquid produced from the first inner layer pipe string are sucked into the gas compressor, and then lifted to the ground after being pressurized, thereby playing the role of draining liquid and recovering gas.

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