Method of using F type well group to exploit non-diagenetic type natural gas hydrates

A natural gas and hydrate technology, which is applied in the direction of production fluid, drilling equipment and methods, and earthwork drilling and production, can solve the problems affecting the economic production of natural gas hydrate, obstacles to commercial production/test production, low production efficiency, etc., to achieve prevention The complexity of controlling accidents and the effects of disasters

Active Publication Date: 2018-09-28
GUANGDONG UNIV OF PETROCHEMICAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the catastrophic risk of non-diagenetic gas hydrate exploitation is a major obstacle to commercial / trial production
In addition, low production efficiency is also an important factor affecting the economical production of gas hydrates

Method used

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  • Method of using F type well group to exploit non-diagenetic type natural gas hydrates
  • Method of using F type well group to exploit non-diagenetic type natural gas hydrates

Examples

Experimental program
Comparison scheme
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Embodiment 1

[0026] Such as figure 1 , figure 2 As shown, in this embodiment, non-diagenetic natural gas hydrate is exploited by F-type well group 5 stage fracturing + chemical artificial well wall + pressure reduction method. The F-type well group includes horizontal wells 10 and deviated wells 9, and the entire well group is completed with casing.

[0027] Drill a deviated well 9 firstly, and drill obliquely from above the unstable stratum 6 to the target point A in the stable stratum 8 below the natural gas hydrate reservoir 7, then run the casing and inject cement to complete the well; among them, the deviated well 9 well The well inclination angle at the bottom is 10°, and the straight-line distance between the target point A of the deviated well 9 and the gas hydrate reservoir 7 is 50m;

[0028] Another horizontal well 10 is drilled, and the horizontal well 10 has a vertical well section 1, a deviated well section 2, an upturned well section 3 and a horizontal well section 4, and ...

Embodiment 2

[0032] Such as figure 1 , figure 2 As shown, this embodiment is F-type well group 11 fracturing sand control + depressurization + CO 2 Exploitation of non-diagenetic gas hydrate by displacement method. The F-type well group includes horizontal wells 10 and deviated wells 9, and the entire well group is completed with casing.

[0033] Drill a deviated well 9 firstly, and drill obliquely from above the unstable stratum 6 to the target point A in the stable stratum 8 below the natural gas hydrate reservoir 7, then run the casing and inject cement to complete the well; among them, the deviated well 9 well The well inclination angle at the bottom is 15°, and the straight-line distance between target point A of the deviated well 9 and the gas hydrate reservoir 7 is 80m;

[0034] Another horizontal well 10 is drilled, and the horizontal well 10 has a vertical well section 1, a deviated well section 2, an upturned well section 3 and a horizontal well section 4, and the vertical we...

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Abstract

The invention relates to a method of using an F type well group to exploit non-diagenetic type natural gas hydrates. The method includes the following steps that step 1, a slant well is drilled, the slant well is slantly drilled from the upper face of an unstable stratum to a target spot A in an underling stable stratum of a natural gas hydrate reservoir, and then a casing pipe is lowered and cement is poured for well completion; step 2, a horizontal well is drilled and is provided with a vertical well section, a deflecting well section, an up-warp well section and a horizontal well section and the vertical well section is located on one side of the well bottom, in the slant direction, of the slant well; step 3, fracturing sand control construction is carried out on the horizontal well, the condition that fracturing seams extend into the reservoir is required, and chemical sand control agents are injected into the fracturing seams and the reservoir; and step 4, the slant well is closedby using a well opening, the horizontal well is opened, and the natural gas hydrates are exploited by adopting CO2 replacement or heat injection or depressurization or a mixing method. The stabilityand patency of a well shaft are improved, the contact area of the well shaft and the reservoir is enlarged, and changing of the phase state of the natural gas hydrates occurs in the stable well shaft;on the one hand, complex accidents and even a disaster caused by uncontrollable shakeout and the uncontrollable changing of the phase state of the natural gas hydrates and the unstable well shaft canbe effectively avoided, and on the other hand, well yield and economic benefits of the natural gas hydrates can be effectively improved.

Description

technical field [0001] The invention relates to a method for exploiting natural gas hydrates by using F-type well groups, which belongs to the technical field of drilling and exploitation of natural gas hydrates, and specifically relates to a comprehensive utilization of F-type well groups, which adopts depressurization method, heating method, CO 2 A method for recovering natural gas hydrates by displacement or hybrid methods. Background technique [0002] Non-diagenetic gas hydrates are mostly buried in undiagenetic strata on the seabed, with shallow buried depths, unstable reservoirs, and unstable overlying strata. Natural gas hydrate is solid under low temperature and high pressure conditions. During the drilling and production of natural gas hydrate, its phase state changes due to changes in system temperature and pressure. If the phase transition is uncontrollable, the volume of natural gas hydrate will expand rapidly, coupled with the instability of formation and well...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/01E21B7/04E21B7/06E21B43/30E21B43/26E21B43/02E21B43/16E21B43/24
CPCE21B7/043E21B7/046E21B7/06E21B41/0099E21B43/01E21B43/02E21B43/164E21B43/24E21B43/26E21B43/305
Inventor 刘大伟刘艳艳刘全稳魏臣兴胡罡
Owner GUANGDONG UNIV OF PETROCHEMICAL TECH
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