Abstract:
This paper is the result of energy exploration engineering.
Objective The primary goal is to identify and classify favorable areas for CBM exploration and development, providing a scientific basis for future exploration efforts in Guizhou Province..
Methods Based on geological exploration data and laboratory sample analyses, key reservoir characteristics of the major coal seams (No. 6, No. 14, and No. 27) were systematically assessed. Parameters such as coal seam thickness, gas content, permeability, reservoir pressure, and coal−body structure were analyzed. Using a five−index evaluation method, 19 gas−bearing areas were classified.
Results (1) The three major coal seams exhibit greater thickness in the southwest and thinner deposition toward the northeast. The average gas content is 11.73 m³/t, with gas accumulation primarily controlled by synclinal structures. (2) Seven extensive gas−bearing areas were identified, with the Bide−Santang Basin and the Jinlong−Qianxi−Jinsha syncline group exhibiting gas contents exceeding 16 m3/t. (3) The average well−tested permeability of the coal seams is 0.173 mD, indicating a medium−low permeability reservoir. Permeability decreases from west to east and with increasing depth, with significant variations across different seams. (4) The average reservoir pressure is 4.98 MPa, with an average pressure coefficient of 0.86, indicating a predominantly underpressured state. A transition from underpressure to normal and overpressure is observed from east to west. (5) Coal structural characteristics vary spatially, with primary and fragmented coal types dominant in the east, while granulated and pulverized coal types are more prevalent in the west.
Conclusion Based on the evaluation, seven Grade I, eight Grade II, and four Grade III favorable CBM areas were identified. The Grade I areas, including the Tucheng, Yangmeishu, Dahebian, Shuigonghe, Bide, Zhitang, and northern Jinlong synclines, demonstrate significant CBM exploration and development potential. The Grade II areas include the Gemudi, Jinpen, Santang, northern Qianxi, Jinsha, Liuchang, and Molaoba synclines, while the remaining synclines are classified as Grade III.