China Shale Gas Exploration: Early Sichuan Basin Longmaxi Shale Gas Stimulation and Completion Case Study

Abstract China has surpassed the US to become the largest energy consumer in the world, and it is projected that China's demand for energy will increase from 97 quadrillion Btus in 2010 to 142 quadrillion by 2040 (ExxonMobil 2013), a 46% increase. EIA estimated China has 1,115 Tcf of risked technically recoverable shale gas resources (EIA 2013), making it an important resource for China's future energy demand. Currently, the majority of China's shale gas exploration and development are focused on three marine shales in and around Sichuan basin: the Silurian Longmaxi, the Cambrian age Qiongzhusi, and Niutitang. Of these, it is estimated that the Longmaxi has the highest risked recoverable shale gas (EIA 2013). However, because of its complex paleo tectonic movement, the Longmaxi formation is a highly fractured and faulted system, which makes it challenging to drill and fracture. This paper is a case study of operational challenges encountered when fracturing the Longmaxi formation. A brief geological review of Sichuan basin geology is discussed to present the origin of the geological complexity. The diagnostic fracture injection test (DFIT), hydraulic fracture job charts, log analysis, and microseismic data during fracture stimulation of a horizontal Longmaxi well is analyzed as an example to show the difficulty operators could experience when fracturing a shale formation developed in such a complex geological environment. Possible solutions are discussed as lesson learnt. The production is also detailed.