A hydrate development device

Abstract

This invention discloses a hydrate development device, belonging to the field of natural gas resource development technology. It includes a support base placed on a seabed stratum, on which a main development well assembly and an auxiliary development well assembly are mounted. The main development well assembly includes a pumping pipeline with its inlet extending into the natural gas hydrate formation and its outlet extending above sea level to connect with the pumping system. The auxiliary development well assembly includes a gas pumping pipeline with its inlet extending into a shallow natural gas layer below the natural gas hydrate formation and its outlet connected to the pumping pipeline. This development device employs a dual-well design, which not only accommodates the shallow natural gas that may be encountered when developing hydrates in shallow strata, avoiding natural gas waste, but also increases hydrate production. Furthermore, the support base not only increases the overall structural bending resistance and support capacity but also facilitates the integration of the main and auxiliary development wells.

Description

Technical Field

[0001] This invention relates to the field of natural gas resource development technology, and in particular to a hydrate development apparatus. Background Technology

[0002] Patent application "201510890553.3", entitled "A System and Method for Co-developing Natural Gas, Water-soluble Gas, and Natural Gas Hydrates", discloses a natural gas hydrate development device, including a first production well assembly, a second production well assembly, a gas-water separation device, a high-pressure pump set, and a gas gathering tank. Both the first and second production well assemblies extend from sea level to a triple-gas stacked reservoir. The first production well assembly is connected to the gas-water separation device and the gas gathering tank via a pipeline, and the second production well assembly is connected to the gas-water separation device and the high-pressure pump set via a pipeline. The gas-water separation device is connected to the high-pressure pump set and the gas gathering tank via a pipeline. Safety valves are installed on both pipelines. By adopting a dual-pipeline co-development model, both natural gas hydrates and free natural gas can be developed, using the economic benefits of natural gas to compensate for the benefits of hydrate extraction. However, the above patent still has several problems: First, the deep-sea seabed strata are relatively soft, and the well depth structure is shallow, making it difficult for the strata to support the production well system; second, the pipelines only have safety relief valves and cannot actively regulate the pressure within the pipelines. Summary of the Invention

[0003] The purpose of this invention is to solve the above-mentioned technical problems and provide a hydrate development device. By setting a support base, the overall structural bending resistance and support force for the development well can be increased to meet the operational requirements and facilitate the integration of the main development well and the auxiliary development well. At the same time, the control valve group between the main development well and the auxiliary development well is connected, which can be adjusted according to the pressure inside the well.

[0004] To achieve the above objectives, the present invention provides the following solution: The present invention discloses a hydrate development device, including a support base placed on a seabed stratum. The support base is provided with a main development well assembly and an auxiliary development well assembly. The main development well assembly includes an oil pumping pipeline, the inlet end of which extends into the natural gas hydrate stratum, and the outlet end of which extends out to sea level and connects to the oil pumping system. The auxiliary development well assembly includes a gas pumping pipeline, the inlet end of which extends into a shallow natural gas layer located below the natural gas hydrate stratum, and the outlet end of which is connected to the oil pumping pipeline.

[0005] Preferably, the outlet end of the air extraction pipeline is connected to the oil extraction pipeline via a control valve assembly.

[0006] Preferably, both the main development well assembly and the auxiliary development well assembly include a vertically arranged support conduit, one end of which extends to the bottom of the support base and the other end of which extends to the top of the support base. The oil pumping line is sleeved in the support conduit of the main development well assembly, and the gas pumping line is sleeved in the support conduit of the auxiliary development well assembly.

[0007] Preferably, a reinforcing rib plate assembly is provided between the supporting conduit and the supporting base.

[0008] Preferably, a main directional casing is provided between the oil pumping pipeline and the support guide of the main development well assembly, with one end of the main directional casing extending above the support base and the other end extending into the natural gas hydrate formation; a secondary directional casing is provided between the gas pumping pipeline and the support guide of the secondary development well assembly, with one end of the secondary directional casing extending above the support base and the other end extending into the shallow natural gas layer.

[0009] Preferably, concrete is poured between the main directional casing and the support guide pipe of the main development well assembly, and between the auxiliary directional casing and the support guide pipe of the auxiliary development well assembly.

[0010] Preferably, both the main directional casing and the auxiliary directional casing include a vertically arranged straight pipe section, an inclined pre-angle pipe section, and a production pipe section. The straight pipe section, the pre-angle pipe section, and the production pipe section are arranged sequentially from top to bottom. The production pipe section is connected to the pre-angle pipe section via a tailpipe suspension. The straight pipe section is connected to the high-pressure wellhead via a connecting conduit. The high-pressure wellhead is fixed to the pipe opening of the supporting conduit located above the supporting base.

[0011] Preferably, the straight pipe section is connected to the high-pressure wellhead via a reducing joint.

[0012] Preferably, both the oil extraction pipeline and the gas extraction pipeline are fixed inside the high-pressure wellhead via tubing hangers, and the high-pressure wellhead in the auxiliary development well assembly is provided with a tubing plug.

[0013] Preferably, the control valve assembly is connected to the oil extraction pipeline and the air extraction pipeline via flexible pipeline and rigid pipeline respectively, and a remote control panel is provided on the support base, which is connected to the control valve assembly via a control pipeline.

[0014] The present invention achieves the following technical effects compared to the prior art:

[0015] 1. The hydrate development device of the present invention is specifically designed for the development of natural gas hydrates. It can meet the operational requirements of deep-water drilling and completion. The support base increases the overall structural bending resistance. Moreover, since the formation structure in deep-water areas is relatively soft, the support base can also increase the support force to meet the operational requirements. In terms of wellhead system design, a combination design of main development well and auxiliary development well is adopted to meet the needs of shallow natural gas that may be encountered when developing hydrates in shallow formations. This not only avoids the waste of natural gas, but also increases the production of hydrates and reduces the damage to development equipment caused by shallow natural gas.

[0016] 2. In this invention, we have added a control valve group connecting the oil extraction pipeline and the gas extraction pipeline, which can adjust and control the pressure in the pipeline according to the formation pressure to meet development needs.

[0017] 3. In this invention, since the entire development well is relatively shallow, in order to increase the levelness of the oil pumping pipeline and the gas pumping pipeline, it is required to perform directional drilling as close to the wellhead as possible. We designed the maximum directional drilling angle and adopted the method of using a straight pipe section plus a pre-directional pipe section for directional drilling.

[0018] 4. In this invention, the guide casing is fixed by pre-filling the annulus with cement to prevent damage to the internal pipelines due to excessive downward pressure during the lowering of the support base. The connecting pipeline adopts a combination of rigid and flexible pipes, with a control valve group in the middle, which can be adjusted according to the pressure inside the well. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained by analyzing these drawings without creative effort.

[0020] Figure 1 A three-dimensional structural diagram of a hydrate development device;

[0021] Figure 2 Exploded view of a hydrate development facility.

[0022] Explanation of reference numerals in the attached figures:

[0023] 1. Support base; 2. Main development well assembly; 3. Auxiliary development well assembly; 4. Control valve assembly;

[0024] 201. Pumping line; 202. Main support guide pipe; 203. Main reinforcing rib plate assembly; 204. Main straight pipe section; 205. Main pre-angled pipe section; 206. Main production pipe section; 207. Main tailpipe suspension; 208. Main reducing joint; 209. Main connecting guide pipe; 210. Main high-pressure wellhead; 211. Main pipeline joint;

[0025] 301. Gas extraction pipeline; 302. Auxiliary support guide pipe; 303. Auxiliary reinforcing rib plate assembly; 304. Auxiliary straight pipe section; 305. Auxiliary pre-angled pipe section; 306. Auxiliary production pipe section; 307. Auxiliary tailpipe suspension; 308. Auxiliary reducer joint; 309. Auxiliary connecting guide pipe; 310. Auxiliary high-pressure wellhead; 311. Auxiliary pipeline joint; 312. Tubing plug;

[0026] 401. Flexible pipeline; 402. Remote control panel; 403. Control pipeline; 404. Rigid pipeline. Detailed Implementation

[0027] 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 analyzed and obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] This embodiment provides a hydrate development device, such as... Figures 1 to 2 As shown, the system includes a support base 1 placed on the seabed strata, on which a main development well assembly 2 and an auxiliary development well assembly 3 are mounted. The main development well assembly 2 includes a pumping pipeline 201, with its inlet extending into the natural gas hydrate formation and its outlet extending above sea level to connect with the pumping system. It is primarily used to extract natural gas hydrates from the seabed strata. The auxiliary development well assembly 3 includes a gas extraction pipeline 301, with its inlet extending into a shallow natural gas layer below the natural gas hydrate formation. Its outlet is connected to the pumping pipeline 201 via a control valve assembly 4. The gas extraction pipeline 301 is mainly used for the development of shallow natural gas and natural hydrates, satisfying the shallow gas potential during hydrate development in shallow strata and increasing hydrate production. The control valve assembly 4 can adjust the pipeline pressure within the gas extraction pipeline 301 and the pumping pipeline 201 according to the formation pressure to meet development needs. The support base 1 can increase the overall structural bending resistance and also increase the support force in the deep-sea formation, effectively integrating the main development well assembly 2 and the auxiliary development well assembly 3 together.

[0029] In this embodiment, as Figures 1 to 2As shown, the main development well assembly 2 includes a main support conduit 202, and the auxiliary development well assembly 3 includes an auxiliary support conduit 302. The support base 1 has two mounting holes, in which the main support conduit 202 and the auxiliary support conduit 302 are vertically installed. One end of the main support conduit 202 extends to the bottom of the support base 1, and the other end extends out of the mounting hole and is located above the support base 1. The pumping line 201 is disposed within the main support conduit 202. One end of the auxiliary support conduit 302 extends to the bottom of the support base 1, and the other end also extends out of the mounting hole and is located above the support base 1. The pumping line 301 is fitted within the auxiliary support conduit 302.

[0030] To improve the stability of the connection between the support conduit and the support base 1, in this embodiment, as follows: Figures 1 to 2 As shown, a main reinforcing rib plate assembly 203 is provided between the main support conduit 202 and the support base 1. An auxiliary reinforcing rib plate assembly 303 is provided between the auxiliary support conduit 302 and the support base 1.

[0031] Furthermore, in this embodiment, as Figures 1 to 2 As shown, a main directional casing is provided between the pumping pipeline 201 and the main support conduit 202. One end of the main directional casing extends above the support base 1, and the other end extends into the natural gas hydrate formation. A secondary directional casing is provided between the gas extraction pipeline 301 and the secondary support conduit 302. One end of the secondary directional casing extends above the support base 1, and the other end extends into the shallow natural gas layer. The main directional casing serves to guide the pumping pipeline 201 and provide an annular passage for it. Similarly, the secondary directional casing serves to guide the gas extraction pipeline 301 and provide an annular passage for it.

[0032] Furthermore, in this embodiment, as Figures 1 to 2 As shown, concrete is poured between the main directional casing and the main support conduit 202, and between the auxiliary directional casing and the auxiliary support conduit 302, to improve the stability of the main directional casing and the auxiliary directional casing, thereby improving the stability of the oil extraction pipeline 201 in the main directional casing and the air extraction pipeline 301 in the auxiliary directional casing.

[0033] In this embodiment, as Figures 1 to 2As shown, the main directional casing includes a main straight pipe section 204, a main pre-angled pipe section 205, and a main production pipe section 206. The main straight pipe section 204, the main pre-angled pipe section 205, and the main production pipe section 206 are arranged sequentially from top to bottom. The main straight pipe section 204 is vertically arranged and connected to the main support guide pipe 202 above the support base 1 through the main high-pressure wellhead 210. The main pre-angled pipe section 205 is installed with an inclined setting. The bottom of the main production pipe section 206 is connected to the main pre-angled pipe section 205 through the main tailpipe suspension 207. The main pre-angled pipe section 205 allows the main production pipe section 206 to be pre-angled to the designed formation by connecting the oil pumping pipeline 201, thereby increasing the horizontality of the main production pipe section 206 and adapting to the shallow well depth of the entire development. Correspondingly, the auxiliary casing includes an auxiliary straight pipe section 304, an auxiliary pre-angled pipe section 305, and an auxiliary production pipe section 306. The auxiliary straight pipe section 304 is vertically arranged and connected to the auxiliary support guide pipe 302 above the support base 1 via an auxiliary high-pressure wellhead 310. The auxiliary pre-angled pipe section 305 is installed with an inclination. The bottom of the auxiliary production pipe section 306 is connected to the auxiliary pre-angled pipe section 305 via an auxiliary tailpipe suspension 307. The auxiliary pre-angled pipe section 305 allows the auxiliary production pipe section 306 to be pre-angled to the designed formation via the gas extraction pipeline 301, thereby increasing the horizontality of the auxiliary production pipe section 306 and adapting to the shallow well depth throughout the development.

[0034] In this embodiment, as Figures 1 to 2 As shown, the main straight pipe section 204 is connected to the main high-pressure wellhead 210 via a main reducer 208, and the main reducer 208 and the main high-pressure wellhead 210 are connected via a main connecting conduit 209. The auxiliary straight pipe section 304 is connected to the auxiliary high-pressure wellhead 310 via an auxiliary reducer 308, and the auxiliary reducer 308 and the auxiliary high-pressure wellhead 310 are connected via an auxiliary connecting conduit 309.

[0035] In this embodiment, as Figures 1 to 2 As shown, the oil extraction pipeline 201 is fixed inside the main high-pressure wellhead 210 via the main tubing hanger. The gas extraction pipeline 301 is fixed inside the auxiliary high-pressure wellhead 310 via the auxiliary tubing hanger, and the auxiliary high-pressure wellhead 310 is equipped with a tubing plug 312.

[0036] In this embodiment, as Figures 1 to 2 As shown, the control valve assembly 4 is connected to the oil extraction line 201 and the air extraction line 301 via a flexible line 401 and a rigid line 404, respectively. The flexible line 401 is connected to the oil extraction line 201 via the main line connector 211, and the rigid line 404 is connected to the air extraction line 301 via the auxiliary line connector 311.

[0037] Furthermore, in this embodiment, as Figures 1 to 2As shown, a remote control panel 402 is provided on the support base 1, and the remote control panel 402 is connected to the control valve group 4 through a control pipeline 403.

[0038] In this embodiment, as Figures 1 to 2 As shown, an installation method for a hydrate development apparatus is provided, including the following steps:

[0039] Step 1: During the production operation, we first fabricate the main development well assembly 2 and the auxiliary development well assembly 3 on the surface. First, we fabricate the main support guide pipe 202 and the auxiliary support guide pipe 302. Both the main support guide pipe 202 and the auxiliary support guide pipe 302 are welded together from three pipe sections, including the surface guide pipe head, the surface guide pipe, and the surface guide pipe string. After welding the main support guide pipe 202 and the auxiliary support guide pipe 302, we fabricate the main directional casing and the auxiliary directional casing. We then weld the main high-pressure wellhead 210, the main connecting guide pipe 209, the main reducing joint 208, the main straight pipe section 204, and the main pre-angle pipe section 205 in sequence. Finally, we insert the auxiliary high-pressure wellhead 310 into the surface guide pipe head of the main support guide pipe 202 and rigidly lock it in place using a connecting locking ring. Similarly, the auxiliary high-pressure wellhead 310, auxiliary connecting pipe 309, auxiliary reducing joint 308, auxiliary straight pipe section 304 and auxiliary pre-inclination pipe section 305 are welded together, and then the auxiliary high-pressure wellhead 310 is seated into the surface pipe head of the auxiliary support pipe 302 and rigidly locked and fixed with a connecting locking ring.

[0040] The second step involves fabricating the main development well assembly 2 and the auxiliary development well assembly 3. Cement grout is then injected into the annulus between the main support conduit 202 and the main directional casing, and between the auxiliary support conduit 302 and the auxiliary directional casing, for fixation. Then, the main support conduit 202 and the auxiliary support conduit 302 are respectively inserted into the two holes on the top plate of the support base 1 and welded to the top plate. During welding, a main reinforcing rib plate assembly 203 is added to the top plate of the support base 1 for the main support conduit 202; and an auxiliary reinforcing rib plate assembly 303 is added to the top plate of the support base 1 for the auxiliary support conduit 302. Additional supports are then installed on the inner side of the support base 1 and fixed to the main support conduit 202 and the auxiliary support conduit 302. After the main support conduit 202 and the auxiliary support conduit 302 are fixed, the control valve assembly 4 is installed. Flexible pipelines 401 are used to connect to the main pipeline connector 211 of the main support conduit 202 and the auxiliary pipeline connector 311 of the auxiliary support conduit 302, respectively. Install a remote control panel 402 at an appropriate position on the top plate of the support base 1, and connect a control line 403 between the control valve group 4 and the remote control panel 402.

[0041] The third step is to lower the support base 1 to the designated seabed stratum.

[0042] Fourth, according to operational needs, the auxiliary development well assembly 3 is installed first. Below the auxiliary pre-angled pipe section 305 of the auxiliary development well assembly 3, the auxiliary tailpipe suspension 307 and the auxiliary production pipe section 306 are installed. The auxiliary production pipe section 306 is introduced into the shallow natural gas formation. Then, an auxiliary oil pipe hanger with a gas extraction line 301 is installed inside the auxiliary high-pressure wellhead 310, so that the lower step of the auxiliary oil pipe hanger contacts the internal step of the auxiliary high-pressure wellhead 310, and the locking ring at the top of the auxiliary oil pipe hanger is locked into the inner locking ring groove of the auxiliary high-pressure wellhead 310. An oil pipe plug 312 is installed on the upper part of the auxiliary oil pipe hanger, and the oil pipe plug 312 is locked into the locking ring groove inside the auxiliary high-pressure wellhead 310 for fixation.

[0043] Fifth, after the auxiliary development well assembly 3 is completed, the work equipment is transferred to the side of the main development well assembly 2. The main tailpipe suspension 207 and the main production pipe section 206 are installed below the main pre-angle pipe section 205 of the main development well assembly 2. The main production pipe section 206 leads directly into the natural gas hydrate formation. According to the work procedure, the main tubing hanger with the pumping line 201 is lowered, so that the lower step surface of the main tubing hanger sits on the inner step surface of the main high-pressure wellhead 210, and the main tubing hanger is secured with a locking ring in the inner locking ring groove of the main high-pressure wellhead 210. Another section of pumping line 201 is connected above the main tubing hanger; this section of pumping line 201 extends to sea level and connects to the pumping system.

[0044] The sixth step is to carry out development and production. In the main development well assembly 2, the production fluid can be directly output to the outside from the inner cavity of the pumping line 201 through the upper part of the main oil pipe hanger. Then, the fluid from the auxiliary development well assembly 3 can enter the main development well assembly 2 through the gas extraction line 301 and the flexible line 401, and then merge with the production fluid of the pumping line 201 to achieve the effect of increasing production.

[0045] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A hydrate development apparatus, characterized in that, The system includes a support base placed on the seabed strata, on which a main development well assembly and an auxiliary development well assembly are mounted. The main development well assembly includes an oil pumping pipeline, the inlet end of which extends into the natural gas hydrate formation, and the outlet end of which extends out to sea level and connects to the oil pumping system. The auxiliary development well assembly includes a gas pumping pipeline, the inlet end of which extends into a shallow natural gas layer located below the natural gas hydrate formation, and the outlet end of which is connected to the oil pumping pipeline. The outlet end of the air extraction pipeline is connected to the oil extraction pipeline through a control valve assembly. Both the main development well assembly and the auxiliary development well assembly include vertically arranged support conduits. One end of the support conduit extends to the bottom of the support base, and the other end extends to the top of the support base. The oil pumping line is sleeved in the support conduit of the main development well assembly, and the gas pumping line is sleeved in the support conduit of the auxiliary development well assembly. A main directional casing is provided between the oil pumping pipeline and the support guide of the main development well assembly. One end of the main directional casing extends above the support base, and the other end extends into the natural gas hydrate formation. A secondary directional casing is provided between the gas pumping pipeline and the support guide of the secondary development well assembly. One end of the secondary directional casing extends above the support base, and the other end extends into the shallow natural gas layer. Concrete is poured between the main directional casing and the support guide pipe of the main development well assembly, and between the auxiliary directional casing and the support guide pipe of the auxiliary development well assembly. Both the main directional casing and the auxiliary directional casing include a vertically arranged straight pipe section, an inclined pre-angle pipe section, and a production pipe section. The straight pipe section, the pre-angle pipe section, and the production pipe section are arranged sequentially from top to bottom. The production pipe section is connected to the pre-angle pipe section via a tailpipe suspension. The straight pipe section is connected to the high-pressure wellhead via a connecting conduit. The high-pressure wellhead is connected to the pipe opening of the support conduit located above the support base. Both the oil extraction pipeline and the gas extraction pipeline are fixed inside the high-pressure wellhead via tubing hangers, and the high-pressure wellhead in the auxiliary development well assembly is equipped with a tubing plug.

2. The hydrate development apparatus according to claim 1, characterized in that, A reinforcing rib assembly is provided between the supporting conduit and the supporting base.

3. The hydrate development apparatus according to claim 1, characterized in that, The straight pipe section is connected to the high-pressure wellhead via a reducing joint.

4. The hydrate development apparatus according to claim 1, characterized in that, The control valve assembly is connected to the oil extraction pipeline and the air extraction pipeline via flexible pipeline and rigid pipeline respectively. The support base is equipped with a remote control panel, which is connected to the control valve assembly via a control pipeline.

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