四川盆地合川-潼南地区雷口坡组一段2亚段泥质白云岩非常规气藏形成条件及勘探方向OA

Well Tongshen16 in Hechuan-Tongnan area of Sichuan Basin has achieved high commercial-gas produc-tion in the 2nd sub-member of the first member of Leikoupo Formation,demonstrating good exploration prospects.Argillaceous dolomite is a newly discovered hydrocarbon-generating lithology in Sichuan Basin.However,its hydro-carbon source,reservoir and hydrocarbon accumulation conditions are not clear,and these key issues restrict the exploration and deployment of argillaceous dolomite.Taking argillaceous dolomite in Leikoupo Formation of Sichuan Basin as the systematic research object,studies on hydrocarbon accumulation conditions such as source rocks and reservoirs are carried out through geochemical analysis such as total organic carbon content(w(TOC))and uncon-ventional reservoir analysis methods such as scanning electron microscopy,high-pressure mercury injection and nu-clear magnetic resonance.The results show that natural gas in the 2nd sub-member of the first member of Leikoupo-Formation of Well Tongshen16 comes from source rocks of Leikoupo Formation itself,and oil and gas accumulate in short distance,with self-generated and self-preserved characteristics.Argillaceous dolomite in the 2nd sub-member of the first member of Leikoupo Formation has certain hydrocarbon generating capacity,which is TypeⅡ2 kerogen with high organic matter maturity.Argillaceous dolomite reservoirsare developed in the 2nd sub-member of the first member of LeikoupoFormation,and the reservoir types are mainly micropores-micro-fractures.Natural gas in Leik-oupo Formation enters argillaceous-dolomite reservoir through conduit systems such as small faults and fractures to accumulate and form reservoirs,and is sealed by plastic gypsum at the top and bottom,which is the important rea-son for high production of Well Tongshen16.Central Hechuan-Tongnan area is the key zone for further exploration.