| Popis: |
There are high-pressure shale gas reservoirs and normal-pressure shale gas reservoirs in the Sichuan Basin and its periphery. In recent years, SINOPEC East China Oil & Gas Company takes technical research for normal-pressure shale gas in the complex tectonic regions of basin margin and the fold belt outside Sichuan Basin in southeastern Chongqing, makes significant progress in exploration and development of normal-pressure shale gas, and forms relatively perfect geological theory and technology series of normal-pressure shale gas after more than ten years of research. The normal-pressure shale gas has the characteristics of complex structure, very different preservation condition, and complex in-situ stress compared with high-pressure shale gas. The exploration and development progress and cognition of normal-pressure shale gas in southeastern Chongqing are systematically summarized from geological characteristics, enrichment laws and exploration and development efficiency: (1)The continental shelf facies in deep-water shelf controls the high-quality shale distribution of normal-pressure shale gas, the multistage tectonism controls the differential distribution of tectonic types, fractures and in-situ stress, and the preservation condition becomes better from east to west and from south to north; (2)Four accumulation-dispersion modes of normal-pressure shale gas were established to guide exploration deployment. In the basin margin area, three 100 billion cubic meters increasing reserves zones of Pingqiao, Dongsheng and Yangchungou were completed in the basin margin, and Nanchuan normal-pressure shale gas field was found. In the basin outside area, some favorable exploration targets were confirmed, such as Wulong Syncline, Daozhen Syncline, and Laochangping Anticline; (3)The development technology policy of normal-pressure shale gas was formulated, controlling factors of productivity were defined, and benefit development was realized.Through systematic summary of previous achievement understanding, exploration and development experience, the challenge was analyzed, and the research direction was cleared, to provide reference for normal-pressure shale gas benefit development in similar areas of South China. |
