Research On Regularities Of Oil-gas Accumulation In Bayantala Region

By using the current materials in the interest of area, based on the research of oil reservoir types, the action of faults in the course of accumulation of oil and gas, the model of accumulation of oil and gas ,the controlling factors, and the main period of formation are summarized, and finally the favorable target of oil and gas is predicted. It's considered that the types of reservoir are fault-anticline, base rock buried hill, fault-barrier, fault, fault-lithology and statagraphy. The current hydrocarbon reservoir currently found mainly distribute in Bayantala, oil and gas mainly distribute in Nantun1 member,Nantun 2 member and Tongbomiao strata.y By geochemistry analysis, it's considered that the main source of oil and gas is the source rock in Nantun formation of second law-lying of the north of Wuerxun depression, the abundant production of hydrocarbon are Yimin 2,3 member sedimentary period. Based on the characteristics of sediment, regional caprock is the mudstone of Damaguhe 1 member formation, which has best sealing ability; while the mudstone of Nantun 1 member is better. By the research of sealing ability of fault, it's considered that the destructiveness of fault to caprock in Damaguhe 1 member formation is less than that of Nantun1 member. Through investigate the vertical openning extent of fault during differant activity periods that mainly inherited activity stages of fault are the early stage of Tongbomiao group - Damaguhe 1 member sedimentary stage and Yimin 2,3 member sedimentary stage - the early stage of Qinyuangang group in Bayantala region. Fault is the mainly migration pathway of oil and gas. Main periods of oil and gas reservoir formation are from the middle stage of Yimin group to the early stage of Qingyuangang group; The models for oil and gas reservoirs have three types. There are oil and gas along the fault migrate short-distance inside source rock , along the fault transport long-distance to outside source rock, along the fault or unconformity surface lateral migrate to outside source rock. Hydrocarbon accumulation is mainly controlled by the distribution of source rocks, the role of fault transporting and sealing and the spatial distribution of unconformity surface. Comprehensive analysis pointed out that the favorable exploration target are the top of the bedrock,Tongbomiao group formation,Nantun 1 member formation and Nantun 1 member formation.In addition, the favorable place of lithologic reservoirs or fault - lithology reservoirs are Tongbomiao group,Nantun 1 member and Nantun 2 member.