Well completion well body structure for changing abandoned coal-bed gas well into empty well

Abstract

The utility model discloses a well completion well bore structure for changing a waste coal-bed gas well into an empty well, which is characterized in that the well bore structure consists of a main branch and a plurality of branches, the main branch is formed by reshaping and repairing an original ground waste coal-bed gas well through a sleeve, and the plurality of branches are formed by windowing and sidetrack drilling on the main branch. The lower portion of the main branch and the lower portion of each branch are communicated with a closed goaf space, and the tree-shaped goaf ground extraction well formed by the well bore structure can achieve gas ground extraction on the multiple closed goaf spaces. According to the well completion well body structure, the abandoned ground well of the coal mine goaf is utilized, gas of the working faces of the multiple goaf is extracted through the abandoned coal-bed gas well, the goaf gas can be extracted with low cost and high efficiency, and the gas extraction effect of the coal mine goaf can be improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a goaf gas treatment technical field, especially to a well completion wellbore structure of abandoned coalbed gas well into goaf well. BACKGROUND

[0002] Goaf gas extraction technology can reduce gas concentration to the maximum extent, guarantee coal mine safety production and reduce air pollution. Common gas extraction technologies include ground drilling extraction, high extraction roadway mining and high drilling mining. The main methods of goaf gas extraction by ground drilling include mining well extraction and goaf well extraction, which can use suitable pre-extraction well transformation or special drilling. According to coalbed gas development experience in coal mine area, ground pre-extraction drilling into mining well and goaf well method is tried in China, and corresponding wellbore structure is formed according to the method, which achieves certain effect. However, the wellbore structure of pre-extraction well into mining well or goaf well has a short service range, limited extraction range and difficult post-extraction guarantee, and the extraction effect is not ideal. SUMMARY

[0003] The utility model discloses a well completion wellbore structure of abandoned coalbed gas well into goaf well, which can efficiently extract goaf gas by transforming the wellbore structure of abandoned coalbed gas well in goaf, realize goaf underground gas treatment and ensure underground safety production while fully utilizing abandoned coalbed gas well in goaf.

[0004] The utility model discloses the technical scheme that a well completion wellbore structure of abandoned coalbed gas well into goaf well, this wellbore structure is formed by a main branch and a plurality of branches, the main branch is formed by the original ground abandoned coalbed gas well after casing shaping repair, and a plurality of branches are formed by windowing sidetracking on the main branch, the lower part of the main branch and each branch is connected with a closed goaf space, and the wellbore structure forms tree-shaped goaf ground extraction well, which can realize gas ground extraction of a plurality of closed goaf spaces.

[0005] Further, the inner diameter of the main branch is 124.26mm, and the diameter of the branch borehole is 114mm.

[0006] Further, the distance between adjacent branch windowing deflecting points is more than 20m.

[0007] Further, the branch includes a deflecting section and a stabilizing section.

[0008] Further, the maximum deflecting rate of the deflecting section is 8° / 30m, and the maximum well inclination of the stabilizing section is 70°.

[0009] Further, the branch further includes an increasing inclination section and a decreasing inclination section.

[0010] The well completion well body structure of the utility model utilizes the abandoned surface well of the coal mine goaf area, realizes that the abandoned coal bed gas well extracts multiple goaf area working face gas, can realize low cost, high efficiency extraction goaf area gas, can improve the coal mine goaf area gas extraction effect.

[0011] No matter from promoting the closing coal mine remaining resources, ground and underground space reuse or eliminating the coal goaf area gas overflow safety hidden danger, and promoting the mine gas utilization to the low carbon environmental protection direction, the gas extraction and utilization mode adopting the technology is worth promoting. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 It is the front view schematic diagram of the well completion well body structure of the utility model;

[0013] Figure 2 It is the plan view schematic diagram of the well completion well body structure of the utility model. DETAILED DESCRIPTION

[0014] In order to better understand the purpose, structure and function of the utility model, the well completion well body structure of the abandoned coal bed gas well changed goaf well of the utility model is further described in detail below in conjunction with the drawings.

[0015] As Figure 1 And Figure 2 As shown in a kind of well completion well body structure of the abandoned coal bed gas well changed goaf well, specifically, a tree-shaped well body structure formed by reforming original surface coal bed gas well, the well body structure is composed of one main branch and multiple branches, the main branch is formed by casing shaping repair of original surface abandoned coal bed gas well, and the inner diameter is 124.26mm, and the lower part of the main branch is connected with one closed goaf space.

[0016] Multiple branches are formed by windowing sidetracking on the main branch, and the distance between adjacent branch windowing build-up points is required to be more than 20m, which is numbered from bottom to top according to the construction sequence of the hole forming process, and the diameter of the branch drilling hole is 114mm, and the lower part of each branch is connected with one closed goaf space.

[0017] Branch mainly includes build-up section and stable section, and according to needs, it can also include build-up section and drop section, the maximum build-up rate of build-up section can reach 8° / 30m, and the maximum inclination of stable section can reach 70°. The tree-shaped goaf surface extraction well formed by the well body structure can realize surface extraction of gas in multiple closed goaf spaces.

[0018] The well completion well body structure of the abandoned coal bed gas well changed goaf well of the utility model is a kind of extraction well completion well body structure of goaf area gas surface extraction, and the tree-shaped well body structure is formed by reforming original surface coal bed gas well, which can efficiently extract gas in multiple closed goaf spaces, and improve the coal mine goaf area gas control effect.

[0019] It can be understood that the utility model is described through some embodiments, and the person skilled in the art knows that various changes or equivalent replacements can be made to these features and embodiments without departing from the spirit and scope of the utility model. In addition, under the guidance of the utility model, these features and embodiments can be modified to adapt to specific conditions and materials without departing from the spirit and scope of the utility model. Therefore, the utility model is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present application belong to the scope protected by the utility model.

Claims

1. A well completion string structure for converting a depleted coalbed methane well into a void recovery well, characterized by, The well structure is composed of a main branch and multiple branches, the main branch is formed by repairing the original surface abandoned coal seam gas well through casing shaping, and the multiple branches are formed by window sidetracking on the main branch, the lower part of the main branch and each branch is connected with a closed goaf space, and the tree-shaped goaf surface drainage well formed by the well structure can realize gas surface drainage of multiple closed goaf spaces.

2. The wellbore completion structure for converting a depleted coalbed gas well to a vacant well according to claim 1, wherein, The inner diameter of the main branch is 124.26 mm, and the diameter of the branch borehole is 114 mm.

3. The wellbore completion structure for converting a depleted coalbed gas well to a vacant well according to claim 1, wherein, The distance between the window sidetracking points of adjacent branches is more than 20 m.

4. The wellbore completion structure for converting a depleted coalbed gas well to a vacant well according to claim 1, wherein, The branch includes a build-up section and a hold section.

5. The abandoned coalbed methane well converted to a depleted well completion wellbore configuration of claim 4, wherein, The maximum build-up rate of the build-up section is 8° / 30 m, and the maximum inclination of the hold section is 70°.

6. The well completion string for converting a depleted coalbed gas well into a vacant well according to claim 4 or 5, characterized in that, The branch further includes a build-up section and a drop section.

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