The Qinshui Basin was an active residual basin in the Mesozoic and Cenozoic periods and is located inside the North China Plate. The Upper Paleozoic strata in the basin have been strongly deformed and have developed a large number of strike-slip faults. The Qinshui Basin has been influenced by compressive stress from the northeast direction since the Himalayan period, and the faults have a dextral strike-slip property. Under the action of such a stress field, the right-slip, right-order faults indicate an extension region, and the right-slip, left-order faults indicate a compression region. Based on this principle, the extension and the compression areas were divided. From northwest to southeast direction in the study area, two types of regions have interactive distribution characteristics. For the Fanzhuang block in the eastern part of the study area, the fault distribution has an ‘S-type’ trend from north to south, and the middle extension region is the ‘elbow’ or the ‘hinge zone’ of the ‘S-type’ area, which can also be called the ‘stress transition zone’. The tectonic stress field of the stress transition zone is complex, and tensile fractures are usually extremely developed with extension tectonics. Gas wells with higher capacity are mainly distributed in the extension zone, while the capacity of the gas wells in the compression area is usually lower. The study showed that the distribution of the gas well capacity is consistent with the tectonic extension and compression analysis, indicating that the tectonic analysis method in this study is reliable. The Upper Paleozoic coal measure strata in the Qinshui Basin represent a whole gas-bearing and stress-bearing system, the tectonic analysis method in this study is also applicable to other types of tight reservoirs for this set of depositional systems.
Volume 128 | Issue 8
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