Multi-branch horizontal well depressurization and heating united mining method for marine hydrates

A horizontal well and multi-branch technology, which is applied in the direction of underwater drilling, fluid extraction, earthwork drilling, etc., to achieve the effects of slowing down the degree of sand production, promoting decomposition, and prolonging the duration of test production

Active Publication Date: 2019-05-17
QINGDAO INST OF MARINE GEOLOGY
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

However, it can also be seen that compared with sandy reservoirs, the average daily gas production of hydrates in silty reservoirs has a greater gap with the industrial gas flow standard, and the extraction efficiency still needs to be greatly improved

Method used

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  • Multi-branch horizontal well depressurization and heating united mining method for marine hydrates

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Embodiment 1

[0047] Example 1, such as figure 1 As shown, the method for depressurization and heating combined production of marine hydrate multi-branch horizontal wells is based on the well-type structure of the main wellbore and multi-branch horizontal wells, using hydraulic slitting and heating control means to connect three-dimensional scattered ore bodies To adapt to the hydrate depressurization mining in silty reservoirs.

[0048] Specifically, it includes the following implementation steps:

[0049] (1) The main borehole is completed

[0050] The main borehole drilling method is to drill the upper layer of the hydrate reservoir and cement the well, then drill to form a 16” main borehole. The main borehole penetrates the reservoir and leaves sedimentation at the bottom of the well below the bottom of the reservoir. pocket;

[0051] The completion mode of the main wellbore is casing completion, and the casing has reserved holes for docking with multi-branch horizontal wells; cement is used ...

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Abstract

The invention discloses a multi-branch horizontal well depressurization and heating united mining method for marine hydrates. For the 'congenital' defects that the marine hydrates are distributed in ascattered manner and cannot self flow and get together, based on well type structure improvement of a 'main borehole + a multi-branch horizontal well', an ore body reservoir is hydraulically cut by avertical hydrate layer to improve the hydrate decomposition efficiency and achieve the design objectives of connecting three-dimensional scattered ore bodies and relieving the problems of a large amount of sand, instability of the reservoir and blockage formed by secondary hydrates. The united mining method comprises the following steps: (1) forming a well by a main borehole; (2) drilling a multi-branch horizontal well: forming a plurality of multi-branch horizontal wells, which form a certain included angle and are distributed in a fixed direction, around the main borehole, and arranging thehorizontal wells in the middle region of a hydrate reservoir, wherein joints between the multi-branch horizontal wells and between the multi-branch horizontal wells and the main borehole are all of sleeve and conventional sand control sieve tube structures; (3) performing limited sand control and reservoir supporting; (4) transforming the reservoir by hydraulic jetting; (5) performing heating toprevent blockage.

Description

Technical field [0001] The invention relates to a combined mining method based on fractal theory for marine hydrate reservoirs with a main well assisted by multi-branch horizontal wells for pressure reduction and heating, and belongs to the technical field of marine resource development engineering. Background technique [0002] As a new type of high-efficiency and environmentally friendly energy, natural gas hydrate is widely distributed in the land permafrost and the seabed of continental margins. The amount of marine hydrate resources is conservatively estimated to be two orders of magnitude higher than that of frozen soil hydrate resources. However, compared with frozen soil hydrate reservoirs, the mining of marine hydrate reservoirs faces more severe technical and environmental problems, which makes marine hydrate research opportunities and challenges coexist. In 2007 and 2015, my country carried out drilling in the Shenhu waters off the northern slope of the South China Sea...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/01E21B43/114E21B43/24E21B7/12
Inventor 胡高伟吴能友万义钊李彦龙黄丽刘昌岭陈强卜庆涛王代刚
Owner QINGDAO INST OF MARINE GEOLOGY
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