Method for designing exploiting wells of multi-layer stacking coal bed gas system

Abstract

The invention relates to a method for designing exploiting wells of a multi-layer stacking coal bed gas system. The designing method includes the steps of (1) ranking reservoirs with the same reservoir pressure into the same gas contained system reservoir; (2) selecting the coal seam with the high capacity for serving as a main target reservoir of coal bed gas exploiting; (3) according to the number of the reservoirs of a multi-seam region gas-contained system, determining the number of the vertically-drilled wells needing to be drilled by a drilling platform, and accordingly determining perforation reservoir positions and non-perforation reservoir positions of the vertically-drilled wells. By means of the method for designing the exploiting wells of the multi-layer stacking coal bed gas system, advantages of the vertical wells and advantages of the cluster wells are combined, and novel cluster well type design is proposed; that is, on the same drilling platform, the coal bed gas vertical wells are drilled in the reservoirs of the gas contained system respectively and are not interfered, coal bed gas in a region is exploited to the maximum degree accordingly, and the effect of increasing the capacity of the coal bed gas wells is achieved.

Description

technical field [0001] The invention relates to a well type design for coal bed gas reservoir mining, in particular to a design method for a well design method for a multi-layer stacked coal bed gas system in a multi-coal seam area. Background technique [0002] At present, the Zhijin-Nayong coalfield in Guizhou Province is a hot reserve area for coalbed methane exploration and development in the south. Coal bed groups of the Upper Permian Longtan Formation in the Zhina coalfield are widely developed, and the coalbed methane pools present different accumulation characteristics from those under the condition of a single coal bed. Some people put forward and preliminarily demonstrated the academic point of view of "multi-layer superposition of independent gas-bearing system layers" by studying the vertical distribution law of geological conditions of Shuigong River syncline coalbed methane in Zhijin-Nayong coalfield. Some people conducted in-depth research on "multi-layer sta...

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Problems solved by technology

[0005] In order to overcome the deficiency that the existing well types cannot exploit coalbed methane resources well in areas with multiple coal seams and multi-layered coalbed methane reservoirs, the present invention provides a method for designing wells for multi-layered stacked coalbed methane systems. The production well design method not only combines the advantages of vertical wells and cluster wells, but also proposes a new cluster well design, that is, on the same drilling platform, one vertical well is drilled into each gas-bearing system layer, and each coal seam The gas wells do not interfere with each other, so that the coalbed methane in the area can be exploited to a certain extent to the maximum extent, and the effect of improving the productivity of the coalbed methane wells can be achieved

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