T-shaped well group and method for exploiting non-diagenetic natural gas hydrates

A technology for hydrate and natural gas, applied in the fields of fluid extraction, coal gasification, and earth-moving drilling, etc., can solve the problems of poor wellbore stability, unstable wellbore, and high risks in the mining process, and achieve increased stability and well control safety, guaranteeing The effect of marine environmental safety, improving single well production and economic benefits

Pending Publication Date: 2020-08-28
GUANGDONG UNIV OF PETROCHEMICAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The invention proposes a T-shaped well group and a method for exploiting non-diagenetic natural gas hydrate, which solves the problems of poor well wall stability, unstable wellbore and high risk in the mining process in the prior art

Method used

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  • T-shaped well group and method for exploiting non-diagenetic natural gas hydrates
  • T-shaped well group and method for exploiting non-diagenetic natural gas hydrates

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Embodiment 1

[0031] like figure 1 As shown, the T-shaped well group includes a vertical well 1 and a first horizontal well 2 sharing a wellhead, all of which are completed with casing. The vertical well target 3 of the vertical well 1 is located in the second stable formation 9 below the reservoir 10, and the distance from the vertical well target 3 to the reservoir 10 is 260 meters (the distance from the seabed to the reservoir 10 is 500 meters); the first horizontal well The target point 4 of the horizontal well of 2, the build-up section, the build-up section, the stabilizing section and the horizontal section are all located in the first stable formation 8 above the reservoir 10, and the length of the horizontal section is 400 meters; the vertical well 1 and the first horizontal well 2 are equipped with a fracturing sand control layer 5, the vertical well fracturing 6 of the vertical well 1 is a horizontal fracture, and the half-length of the vertical well fracturing 6 is 80 meters; th...

Embodiment 2

[0040] like figure 2As shown, the T-shaped well group includes a vertical well 1, a first horizontal well 2 and a second horizontal well 11 sharing one wellhead, all of which are completed with casing. The vertical well target 3 of the vertical well 1 is located in the second stable formation 9 below the reservoir 10, and the distance from the vertical well target 3 to the reservoir 10 is 480 meters (the distance from the seabed to the reservoir 10 is 800 meters); the first horizontal well The target point 4 of the horizontal well 2, the build-up section, the build-up section, the stabilizing section and the horizontal section are all located in the first stable formation 8 above the reservoir 10, and the length of the horizontal section is 1000 meters; the water in the second horizontal well 11 The target point of the flat well, the build-up section, the build-up section, the stabilizing section and the horizontal section are all located in the first stable formation 8 above...

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Abstract

The invention provides a T-shaped well group and a method for exploiting non-diagenetic natural gas hydrates. The T-shaped well group comprises a vertical well and a horizontal well located on one side of the vertical well, and the vertical well and the horizontal well share the same wellhead; a vertical well target point is located in a stable formation under a reservoir; a deflecting section, adeflection increasing section, a deflection stabilizing section and a horizontal section of the horizontal well are all located in a stable formation over the reservoir, and a horizontal well target point is located in the reservoir or the stable formation over the reservoir; both the vertical well and the horizontal well are provided with fracturing sand prevention layers, and a vertical well fracturing seam is a horizontal seam; and horizontal well fracturing seams are vertical seams, the lower ends of the horizontal well fracturing seams extend into the reservoir, and the number of the horizontal well fracturing seams is not less than two sections. The T-shaped well group and the method for exploiting the non-diagenetic natural gas hydrates have the beneficial effects that the verticalwell target point, and the deflecting section, the deflection increasing section, the deflection stabilizing section and the horizontal section of the horizontal well in the T-shaped well group are all arranged in the underlying stable formation or the overlying stable formation of the reservoir so that not only can the stability of wellbores of the whole well group and well control safety be improved, but also the contact area between the wellbores and the reservoir can be increased.

Description

technical field [0001] The invention relates to the technical field of natural gas hydrate drilling and production, in particular to a T-shaped well group and a method for producing non-diagenetic natural gas hydrate. Background technique [0002] Non-diagenetic natural gas hydrates are mainly buried in the shallow seabed, and their reservoirs are not hard or non-diagenetic and appear as quicksand. Therefore, wellbore instability for the exploitation of non-diagenetic natural gas hydrates occurs frequently. If a large amount of quicksand is produced and the reservoir is mined out, the overlying strata will become unstable and collapse, and even cause catastrophic accidents such as submarine landslides or tsunamis. [0003] Non-diagenetic natural gas hydrate is solid under low temperature and high pressure conditions. During the mining process, as the surrounding temperature and pressure change, its phase state will change from solid to gas, and water will be produced at the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/30E21B43/295E21B43/22E21B43/24E21B43/16E21B43/26E21B43/02E21B43/01
CPCE21B43/01E21B43/02E21B43/16E21B43/24E21B43/26E21B43/295E21B43/305
Inventor 刘大伟刘艳艳郭柏云刘全稳魏臣兴张帮亮王林陈琦吴其林胡罡
Owner GUANGDONG UNIV OF PETROCHEMICAL TECH
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