RU2292449C2 - Method for industrial extraction of methane from methane-coal deposit - Google Patents

Abstract

FIELD: mining industry, in particular, methods for extracting methane from methane-coal deposits; possible use for multi-bed coal deposits with heterogeneous area-wise and cut-wise geologic and physical characteristics of coal beds.

SUBSTANCE: operation object is selected in accordance to method. The latter is drilled by wells and operated. In case of multi-bed deposit operation objects are divided on groups. Extraction is started with first priority object. The latter is extracted by a net of wells. After that other objects are extracted. Extraction of next object is begun on reaching of its unloading for 5-10% of original rock pressure.

EFFECT: efficient extraction of methane-coal deposit with large scale extraction of methane as independent mineral resource with minimization of material costs and more full extraction of methane from coal beds.

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Description

The method relates to the mining industry, in particular to methods for producing methane from methane-coal deposits, and will be used for multi-layer coal deposits with geological and physical characteristics of coal seams that are heterogeneous in area and section. For example, the Kolchuga series in the Kuznetsk basin contains over 130 coal seams with a total thickness of more than 100 m in the cut interval of about 2500 m, differing in petrographic composition, metamorphism, sorption and filtration characteristics. The application of the method is possible both on unloaded and on formations of methane deposits not unloaded from rock pressure at depths of up to 1500 m and more.

Known methods for the extraction of methane from coal seams by wells drilled from the surface, in particular for AS No. 1177510, providing for the extraction of gas from a coal seam in order to reduce gas emissions in mine workings. When using these methods, the location and number of wells is determined by the development of mine workings of the mine. Degassing wells do not constitute a single drilling scheme for the field and they are drilled into a single formation. At the same time, the goal of methane production as an independent mineral in industrial volumes is not set, which is the disadvantage of these methods. Another drawback is that such wells are designed for the depths of mine workings and the involvement of gas reserves at great depths is not provided for.

Extraction of methane as an independent mineral is most actively carried out in the United States. The exploitation of methane deposits is carried out by wells drilled from the surface. In 2003, the United States operated more than 15,000 methane-producing wells in 10 major methane-coal basins. The density of the grid of wells varies from 16-128 ha / well. The production of methane from coal seams in 2003 amounted to 47 billion m ³ .

One of the closest to the proposed production method is the method described in US patent No. 3934649, which involves drilling a field in a square grid of wells, injecting an inert gas cell into one of the wells and extracting methane from other wells. Since the main feature of the US methane-gas basins being developed by the gas field is the presence of one layer of complex structure or a pack of adjacent layers in a small interval of the section (100-120 m), these layers are developed simultaneously by a single grid of wells. However, this method is of little use in the conditions of the Kuzbass, Donbass, Pechora and other basins of the Russian Federation.

The objective of the proposed method is the effective development of methane deposits with large-scale production of methane as an independent mineral while minimizing material costs and the most complete extraction of methane from coal seams.

The problem is solved as follows. In the known method for the development of a methane-coal deposit, which includes the isolation of a production facility, its drilling by wells and operation, if applied to the development of a multilayer field, production facilities are divided into groups, development begins with a priority facility, which is developed by a grid of wells, and then proceed to development of subsequent objects. Moreover, the development of subsequent facilities begins upon reaching the limit values of economic profitability of the development of a priority facility. The development of the subsequent facility begins when it is unloaded by 5-10% of the initial rock pressure.

In the case of the location of subsequent facilities above the priority, development is carried out through the existing grid of wells, in the case of the location of subsequent facilities below the priority, development is carried out through an independent grid of wells.

The method is as follows.

The field is drilled from the surface by a system of wells located according to the areal layout of wells for various purposes, providing methane production as an independent mineral in specified volumes from productive formations with geological and physical characteristics that are heterogeneous in area and section. For the purpose of methane production, coal seams containing methane throughout the coal-bearing stratum section to the depths of technologically accessible and economically feasible are involved in active well development. The novelty of the proposed method for the large-scale production of methane from a multi-layer methane-coal deposit is the selection of production facilities, the selection of a priority facility, drilling and operation of a priority facility, involvement in the development of subsequent facilities after their unloading by 5-10% of the initial rock pressure, drilling with an independent system of wells and operation formations not covered by discharge. Thus, simultaneous-sequential production of methane from all productive formations of a multilayer methane-coal deposit is carried out. The economic effect of the proposed method is achieved due to the most complete extraction of methane from the reservoirs while reducing capital expenditures for well drilling.

At the same time, a decrease in the gas content of coal seams will reduce the cost and gas hazard of their subsequent development by mines.

The implementation of the proposed method for the extraction of methane from a multi-layer methane-carbon deposit begins with the allocation of field facilities and determining the order of their commissioning, the basis of which are the specific mining and geological conditions of the field and pre-project feasibility studies.

A production facility is a group of coal seams (with a total thickness of more than 10 m) in the bedding range of 100-250 m. Thus, simultaneous drainage of 3 or more coal seams is carried out.

If the primary object is the lower group of reservoirs, then the field is drilled according to the areal layout of wells, the density of which is determined by economic feasibility. As the subsequent facilities are unloaded from the rock pressure by 5-10% of the initial, the grid of wells for their development is formed from the wells that initially operate the lower facility, according to the areal layout of the wells. As the methane reserves are depleted as a priority production facility, wells are transferred to overlying facilities, increasing the drainage area and the volume of methane produced.

If there is a highly productive coal-methane seam in the section of the deposit, a well grid from the wells of the primary object is formed for its advanced development. Subsequently, they are isolated and returned to the primary facility or included in the grid of wells operating another facility.

If the primary object is a group of productive formations in the middle part of the section, then the operation of the underlying object is carried out by an independent grid of wells with their subsequent transfer to overlying formations. The density of the grid of wells is determined by economic feasibility. Since these facilities will be operated simultaneously, this will lead to an increase in production volumes.

In the case of field equivalence of groups of formations, their operation is carried out according to independent well placement schemes.

In order to intensify the production and completeness of methane extraction from coal seams within the framework of the implemented well placement scheme, various methods are used to increase the gas recovery of the seams, including borehole and surface sources of dilatation-wave action.

To date, the production of methane from coal seams on an industrial scale in Russia is not performed. The proposed method will allow to involve in the industrial development the reserves and resources of methane from the methane-coal basins of the Russian Federation, estimated at almost 50 trillion m ³ , and will ensure the most complete extraction of methane from coal seams.

Information sources

1. Karasevich A.M., Khryukin V.T., Zimakov B.M. and others. The Kuznetsk basin is the largest raw material base for commercial methane extraction from coal seams. Academy of Mining Sciences, M., 2001 - 63 p.

2. Nozhkin N.V. Early degassing of coal deposits - M .: Nedra, 1979-571 s.

3. Nozhkin N.V., Bukhantsov A.I. Analysis of well flow rates during the early degassing of coal-bearing strata. - Ecotechnology and resource saving (Scientific and technical journal of NAS of Ukraine), No. 1, 1994 - p.12-19.

4. Puchkov L.A., Yarunin S.A., Krasyuk N.N. Degassing and extraction of methane from coal deposits. Mountain news and analytical bulletin. - M .: MGGU, 1995, No. 1, pp. 7-13.

5. Yarunin S.A., Lukash A.S., Konarev V.V. Experience of hydrodynamic impact on a coal-bearing massif through a well with a horizontal end of the trunk. - Coal, No. 7, 1990. - p. 18-20.

6. Slastunov S.V. Advance degassing and extraction of methane from coal deposits. - M: MSU, 1996 - 356 p.

7. Puchkov L.A., Slastunov S.V., Fedunets B.I. Prospects for methane production in the Pechora coal basin. -M.: Moscow State University for the Humanities, 2004 .-- 496 p.

Claims (3)

1. A method for the commercial production of methane from a methane-coal deposit, which includes isolating a production facility, drilling it with wells and operating, characterized in that in the case of a multi-layer field, production facilities are divided into groups, development begins with a priority facility, which is developed by a grid of wells, and then proceed to the development of subsequent facilities, while the development of the subsequent facility begins upon reaching its discharge by 5-10% of the initial rock pressure. 2. The method according to claim 1, characterized in that in the case of the location of subsequent objects above the priority development is carried out through the existing grid of wells. 3. The method according to claim 1, characterized in that in the case of the location of subsequent objects below the priority development is carried out through an independent grid of wells.