| Author's Name: GONG Yi, LI Tianyu, WU Kaikai, BAO Hanyong, WANG Jin, JIN Aimin, LOU Zhanghua, LI Mengyao |
| The preservation condition is the key to the enrichment and high yield of shale gas. Based on geological, drilling, logging and seismic data, the characteristics of caprock, roof and floor, fluid pressure and structure of Fuling shale gas field are analyzed. The main indexes controling shale gas preservation are studied from macroscopic and microscopic aspects. The plane difference of shale gas preservation conditions in Fuling shale gas field is evaluated quantitatively or semi quantitatively. The results show that multiple sets of regional caprocks are developed in the study area, among which the Middle Silurian Xiaoheba Formation-Hanjiadian Formation is the most widely distributed and has the best sealing ability. The roof and floor of shale gas reservoir are good, which is a type of “upper cover and lower plugging”. Besides the good sealing performance of regional cap rock and roof and floor, the shale layers also have good self-sealing performance. According to the formation deformation and fault development of Wufeng Formation- Longmaxi Formation, the study area is divided into east zone and west zone by Shimen-Jinping fault zone. The liquid pressure in the east zone is relatively low, the structural deformation and fault development degree are higher than those in the west zone, and the preservation condition of the west zone are better than those of the east zone. The middle structural layers containing gas bearing shale can be divided into 9 types of local structural styles and 5 types of structural deformations. The preservation conditions of shale gas in different structural deformation blocks are comprehensively evaluated. Jiaoshiba box-shape anticline and Jiangdong slope are the best, follows the Pingqiao fault anticline. |
