Variational Reservoir Characteristics of the Wufeng-Longmaxi Formation from Different Sedimentary Region and Its Implications in Southeastern Sichuan Basin, China.

Abstract

Shale gas plays a far-reaching role for meeting the worldly increasing energy demand; however, shale gas development exhibits variable situations for a same geological formation at different sedimentary locations, for example, Wufeng-Longmaxi shale. This work introduced three shale gas parameter wells-target strata of Wufeng-Longmaxi shale-aiming to explore the diversity of reservoir characteristics and its implication. Herein, the mineralogy, lithology, organic matter geochemistry, and trace element analyses of the Wufeng-Longmaxi formation in the southeast Sichuan Basin were evaluated in detail. Meanwhile, this work analyzed the deposit source supply, original hydrocarbon generation capacity, and sedimentary environment of Wufeng-Longmaxi shale. The results show that abundant siliceous organisms may be involved in the shale sedimentation process in the YC-LL2 well. Besides, the hydrocarbon generation capacity of shale in the YC-LL1 well is better than that in the YC-LL2 and YC-LL3 wells. Moreover, the Wufeng-Longmaxi shale in the YC-LL1 well was formed in a strongly reducing and hydrostatic environment, while that in the YC-LL2 and YC-LL3 wells is in a relatively weakly redox environment with poor conditions to preserve organic matter. Hopefully, this work offers salutary information for development of shale gas from a same formation but sedimented from different locations.