2022-07-01

China gains another trillion cubic meters of shale gas resources

By yqqlm yqqlm

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China gains another trillion cubic meters of shale gas resources

Well Xinye 1, with a drilling depth of 5756 meters, is a deep shale gas risk exploration well deployed by Sinopec exploration company in Xinchang structure, Qijiang District, Chongqing. The Xinchang structure belongs to the complex structural belt in the Southeast Sichuan basin margin geologically. Previous studies have shown that the ultra deep shale gas in this structural belt has a large favorable area and large resources, and it is an important field for Sinopec to increase reserves and production of shale gas.

The average depth of “Xinchang South Dongxi Dingshan Lintan field” is more than 3500 meters, of which the deepest drilled well Dingye 8 gas reservoir reaches 4614 meters. Generally speaking, shale gas buried more than 3500 meters is defined as deep shale gas. Deep shale gas passes through many strata, and there are many world-class problems such as large shale burial depth and complex geostress. It has high technical requirements and is difficult to explore and develop. If the development of shallow shale gas is to expand the “sheep’s intestines” into “highways”, then the development of deep shale gas is to build mountains and bridges on the Qinghai Tibet Plateau and build complex and staggered “mountain roads”. We can imagine the difficulty. After making a major exploration breakthrough in Fuling shale gas field in 2012, Sinopec turned its attention to the complex structural belt on the southeastern Sichuan basin margin, established a deep shale gas technology research team, and continued to carry out technical research such as deep shale gas target evaluation. The research has formed a deep shale gas backlog fracturing technology, achieved 100% high-quality shale penetration rate, and all fracturing equipment, tools and materials have been localized, significantly reducing construction costs. In 2019, strategic breakthroughs were made in deep shale gas exploration. After that, the exploration of deep shale gas was further promoted, and trillions of cubic meters of shale gas resource positions were implemented.

Sinopec attaches great importance to deep shale gas exploration, and innovates and forms deep shale gas exploration theory and technology. In 2017, Sinopec established a deep shale gas research leading group and Dongxi structure deep shale gas research pilot area to concentrate on theoretical and technological research. After years of comprehensive research and exploration practice, we have formed a theoretical understanding of deep shale gas geology, successfully revealed the pore development and maintenance mechanism of deep-water shelf facies deep-seated shale, and identified the key elements that deep-seated shale can develop “high porosity” high-quality reservoirs and the deep-seated “dessert” target; Forming deep shale gas dessert prediction technology, proposing that “high-quality shale development, high fluid pressure, micro fracture development and low ground stress” are the key elements of deep dessert evaluation, and innovating dessert prediction technology based on high-precision seismic exploration; The formation of deep shale gas fracturing engineering technology effectively solves the problems of deep shale, such as large burial depth, strong plasticity, high in-situ stress, and great difficulty in fracturing transformation, and forms a three-dimensional fracture network fracturing technology of deep shale, “dense cutting, pressurized expansion, balanced extension, and filling”.

Next, Sinopec will strengthen the fine evaluation of Xinchang structural targets, strengthen the overall evaluation and deployment of “Xinchang South Dongxi Dingshan Liangcun North” in Southeast Sichuan, and strive to achieve new exploration breakthroughs.