Geological conditions and exploration potential for shale gas in Upper Permian Wujiaping Formation in the region of western Hubei-eastern Chongqing

Abstract

The Upper Permian Wujiaping Formation shale in the region of western Hubei and eastern Chongqing has been found qualified for shale gas accumulation in early exploration activities, but the potential for shale gas exploration is still unclear. Based on the core analysis and test data of well Jy3, combined with regional seismic, testing and logging data of this well and wells nearby, the shale distribution, quality, gas-bearing properties, preservation conditions and resource scale of the second member of Wujiaping Formation were discussed. The results showed that the organic-rich shale of deep-water shelf facies and slope to shallow shelf facies were developed and they appeared to be thin in the southwest and thick in the northeast. The shale was mainly composed of quartz (averages 43.10%), clay minerals (average 21.95%) and calcite (averages 17.20%). The organic matter is rich (average TOC value of 8.77%), mainly of type Ⅱ1 kerogen, high thermal maturity (average converted %Ro value of 2.06%), excellent porosity (average value of 5.59%) and good gas bearing property (total gas content averages 3.73 m3/t). The Wujiaping Formation in the Hongxing area is the most promising replacement strata and area for shale gas exploration and development, which shares the largest shale thickness, the best preservation condition, and the most abundant resource.

Keywords

• shale gas
• geological condition
• exploration potential
• wujiaping formation
• western hubei-eastern chongqing region