阅读说明：本技术 一种基于深水吸力锚的天然气水合物水平分支井开采方法 (Natural gas hydrate horizontal branch well exploitation method based on deepwater suction anchor ) 是由 秦绪文 寇贝贝 李博 谢文卫 钟奕昕 于彦江 卢秋平 李晶 于 2020-07-28 设计创作，主要内容包括：本发明涉及天然气水合物开采附属装置的技术领域,特别是涉及一种基于深水吸力锚的天然气水合物水平分支井开采方法,可提高水合物单井产能、降低单井建井成本、提高水合物开采经济技术指标；包括以下步骤：(一)、在井位下入深水吸力锚井口,通过吸力锚内筒进行钻井作业；(二)、下入带有套管分叉系统工具的套管串,以套管分叉系统中的套管分叉短节为引导,完钻多口水平分支井；(三)分别在每口裸眼水平井中使用鱼骨刺工具对水合物储层进行增产改造作业；(四)、在鱼骨刺管柱中坐挂防砂筛管；(五)、建立完整的基于深水吸力锚的天然气水合物水平分支井井身结构。(The invention relates to the technical field of auxiliary devices for exploiting natural gas hydrates, in particular to a method for exploiting a natural gas hydrate horizontal branch well based on a deepwater suction anchor, which can improve the single-well productivity of hydrates, reduce the single-well construction cost and improve the economic and technical indexes of hydrate exploitation; the method comprises the following steps: the method comprises the following steps that (1) a deep water suction anchor wellhead is arranged below a well position, and drilling operation is carried out through a suction anchor inner cylinder; secondly, a casing string with a casing branching system tool is put in, and a casing branching short section in the casing branching system is used as a guide to finish drilling a plurality of horizontal branch wells; thirdly, performing yield increasing transformation operation on the hydrate reservoir by using a fishbone tool in each open hole horizontal well; fourthly, hanging a sand control screen pipe in the fishbone tubular column; and (V) establishing a complete natural gas hydrate horizontal branch well body structure based on the deepwater suction anchor.)

1. A natural gas hydrate horizontal branch well exploitation method based on a deepwater suction anchor is characterized by comprising the following steps:

the method comprises the following steps that (1) a deep water suction anchor wellhead is arranged below a well position, and drilling operation is carried out through a suction anchor inner cylinder;

secondly, a casing string with a casing branching system tool is put in, and a casing branching short section in the casing branching system is used as a guide to finish drilling a plurality of horizontal branch wells;

thirdly, performing yield increasing transformation operation on the hydrate reservoir by using a fishbone tool in each open hole horizontal well;

fourthly, hanging a sand control screen pipe in the fishbone tubular column;

and (V) establishing a complete natural gas hydrate horizontal branch well body structure based on the deepwater suction anchor.

2. The method for exploiting the natural gas hydrate horizontal branch well based on the deepwater suction anchor as claimed in claim 1, wherein for a single wellhead deepwater suction anchor wellhead, the suction anchor comprises an inner cylinder, the establishment of a shaft can be completed, and according to the number of branch channels of a casing branching system, a corresponding number of horizontal branch wells can be drilled.

3. The method for exploiting the natural gas hydrate horizontal branch well based on the deepwater suction anchor as claimed in claim 2, wherein for the multi-wellhead deepwater suction anchor, the suction anchor comprises a plurality of inner cylinders, each inner cylinder can complete the establishment of a shaft, and then according to the number of the branch channels of the casing branching system, the number of the horizontal branch wells which can be drilled is the product of the number of the inner cylinders of the suction anchor and the number of the branch channels of the casing branching system.

4. The method for exploiting the natural gas hydrate horizontal branch well based on the deepwater suction anchor as claimed in claim 3, wherein the number of the inner cylinders of the suction anchor is equal to that of the well heads.

Technical Field

The invention relates to the technical field of natural gas hydrate exploitation auxiliary devices, in particular to a natural gas hydrate horizontal branch well exploitation method based on a deepwater suction anchor.

Background

At present, natural gas hydrate reserves in the global sea area are all in a trial production stage, theoretical exploitation technologies mainly include a thermal excitation method, a depressurization method, a chemical reagent method, a CO2 replacement method, a fracturing exploitation method, a solid exploitation method and the like, the thermal excitation method and the depressurization method are most common in the actual trial production process, a straight well is mostly adopted in the design of a well body structure, a horizontal well body structure is firstly adopted by the Guangzhou ocean geological survey bureau of China for depressurization trial production, and the trial production yield and the stable production period of the natural gas hydrate are greatly improved on the basis of the original trial production of the straight well body structure.

At present, the yield required by commercial exploitation is still a certain gap by adopting a horizontal well depressurization exploitation method, and other scientific and effective yield increasing technologies need to be combined. And no matter the vertical well body structure or the horizontal well body structure, only one well track is provided, the single well control area is small, the further improvement of the yield is limited, the trial production cost is high, and the improvement effect of the depressurization method and the thermal excitation method on the yield of the natural gas hydrate is limited.

Disclosure of Invention

In order to solve the technical problems, the invention provides the natural gas hydrate horizontal branch well exploitation method based on the deep water suction anchor, which can improve the hydrate single well productivity, reduce the single well construction cost and improve the hydrate exploitation economic and technical indexes.

The invention relates to a natural gas hydrate horizontal branch well exploitation method based on a deepwater suction anchor, which comprises the following steps:

the method comprises the following steps that (1) a deep water suction anchor wellhead is arranged below a well position, and drilling operation is carried out through a suction anchor inner cylinder;

secondly, a casing string with a casing branching system tool is put in, and a casing branching short section in the casing branching system is used as a guide to finish drilling a plurality of horizontal branch wells;

thirdly, performing yield increasing transformation operation on the hydrate reservoir by using a fishbone tool in each open hole horizontal well;

fourthly, hanging a sand control screen pipe in the fishbone tubular column;

and (V) establishing a complete natural gas hydrate horizontal branch well body structure based on the deepwater suction anchor.

The invention relates to a natural gas hydrate horizontal branch well exploitation method based on a deep water suction anchor.

The invention relates to a natural gas hydrate horizontal branch well exploitation method based on a deepwater suction anchor.

According to the natural gas hydrate horizontal branch well exploitation method based on the deepwater suction anchor, the number of the inner cylinders of the suction anchor is equal to that of the well mouths.

Compared with the prior art, the invention has the beneficial effects that: 1. the natural gas hydrate horizontal branch well exploitation method based on the single-wellhead deepwater suction anchor can realize a single-shaft multi-horizontal branch well body structure on the single-wellhead deepwater suction anchor through a sleeve branching system tool, improve the single-shaft control area, increase the single-shaft productivity, effectively reduce the well construction cost and improve the exploitation economy; 2. the natural gas hydrate horizontal branch well exploitation method based on the multi-wellhead deepwater suction anchor can realize a multi-well-barrel multi-horizontal branch well body structure on the multi-wellhead deepwater suction anchor through a sleeve branching system tool, and further improve the control area of a pilot-production well, further increase the productivity of the pilot-production well, further effectively reduce the well construction cost and further improve the exploitation economy on the basis of the natural gas hydrate horizontal branch well exploitation method based on the single-wellhead deepwater suction anchor; 3. in the exploitation method of the well body structure, fishbone reconstruction technology is implemented on each horizontal open hole well in each shaft, so that the seepage area of a single well bore is further increased, the seepage resistance around the well is improved, and the productivity of the single well bore is improved, thereby further improving the productivity of the single well bore; 4. the application of the deep water suction anchor well mouth can improve the well mouth stability and ensure the implementation of the deep water shallow layer horizontal well technology, meanwhile, the application of the multi-well mouth deep water suction anchor and the casing pipe branching system tool can further improve the number of horizontal branch wells, the method is very suitable for the construction of a deep water development well pattern, the cost is low, the economy of the construction of the development well pattern can be effectively improved, and the commercial development process of the sea area hydrate reservoir is promoted.

Drawings

FIG. 1 is a front view of a gas hydrate horizontal multilateral well production method based on a single wellhead deepwater suction anchor;

FIG. 2 is a plan view of a gas hydrate horizontal multilateral well production method based on a single wellhead deepwater suction anchor;

FIG. 3 is a left side view of a natural gas hydrate horizontal multilateral well production method based on a multi-wellhead deepwater suction anchor;

FIG. 4 is a front view of a gas hydrate horizontal multilateral well production method based on a multi-wellhead deepwater suction anchor;

FIG. 5 is a plan view of a gas hydrate horizontal multilateral well production method based on a multi-wellhead deepwater suction anchor;

in the drawings, the reference numbers: 1. a single wellhead deepwater suction anchor wellhead; 2. a technical sleeve; 3. the sleeve is forked; 4. hanging a tail pipe; 5. a screen pipe packer; 6. branching fishbone; 7. fishbone and production casing string; 8. a sand control screen pipe; 9. a wellbore; 10. a horizontal multilateral well 1; 11. a horizontal multilateral well 2; 12. a multi-wellhead deepwater suction anchor wellhead; 13. a wellbore 1; 14. a wellbore 2; 15. a horizontal multilateral well 1; 16. a horizontal multilateral well 2; 17. a horizontal multilateral well 3; 18. a horizontal lateral well 4.

Detailed Description

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

As shown in fig. 1 to 5: