| Summary: | Exploration of the Sinian-Lower Paleozoic formations in the Sichuan Basin starts from the 1950s, and is tortuous and complex. To summarize the exploration experiences is of great significance of reference for exploration of oil and gas in deep carbonate rocks of the Sichuan Basin. Gas accumulation in the Anyue oversize gasfield is chiefly controlled by the Deyang-Anyue intra-platform rift and central Sichuan paleouplift. The intra-platform rift controls the scale hydrocarbon generation center and effective hydrocarbon plays. The Anyue gasfield is characterized by near-source hydrocarbon accumulation. The marginal zone of intra-platform rift and high part of the paleouplift control the scale distribution of favorable facies belts of reservoir development, and overlapped by paleokarstic reformation, the reservoirs are widely distributed. The intra-platform rift and paleouplift jointly control formation of the scale traps and hydrocarbon enrichment. Gas reservoir features and major controlling factors for hydrocarbon accumulation have some differences in the main play strata, such as Longwangmiao Formation, and Member 4 and Member 2 of Dengying Formation. The gas reservoir in the Longwangmiao Formation is a lithologic gas reservoir under the tectonic setting, and the inherited paleouplift is a key for reservoir formation and hydrocarbon accumulation. The gas reservoir in the Member 4 of Dengying Formation is mainly controlled by large structural-stratigraphic composite traps, and the gas reservoir in the Member 2 of Dengying Formation is the structural trap. Distribution of the large gasfields in the Dengying Formation is controlled by the intra-platform rift, near-source hydrocarbon-reservoir configuration controlled by the ancient erosion plane and stratigraphic sealing in the updip direction. For exploration and development of the Anyue gasfield, four series of technologies are developed, namely, reservoir seismic fine description technology, well logging fine evaluation technology of gas layers, fast drilling technology of complex strata, and stimulation technology for high temperature and high pressure gas layers. Technical progresses provide powerful guarantee for efficient exploration and development of the oversize gasfields. Keywords: Anyue gasfield, Dengying Formation, Longwangmiao Formation, Gas reservoir feature, Enrichment regularity, Exploration and development technology
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