Study On Fault System And Fault Controlling Hydrocarbon Accumulation In Middle Fault Depression Belt In Hailer-Tamtsag Basin

To clarify the coupling relationship between fault development characteristics andhydrocarbon accumulation at middle fault depression belt in Hailer Tamtsag Basin, this paperstudy on the basis of tectonic setting in Hailer Tamtsag Basin, through the study of differenttectonic fault zone combing and anatomy, in-depth analysis of fault developmentcharacteristics、activity patterns and evolutionary history, analysis the fault controllinghydrocarbon accumulation mechanisms and oil and water distribution.The results show that, Hailer Tamtsag Basin is divided vertically into upper and lowersets of fault systems, the limiting strata is Damoguaihe group. The upper fault system ismainly distributed in the Damoguaihe group, yimin group, and qingyuangang group, thelower fault system is mainly distributed in the tongbomiao group, nan1and nan2. Thefoundational fault in Hailer Tamtsag Basin is mostly listric fault, main boundary faultsgenerally converges down to the middle crust, fault in faulted period and fault-depressiontransform period is mostly Non-rotating flat normal fault. The combination of form betweenthe upper and lower fault system and internal faults have large differences. There are5faultscontrolling hydrocarbon accumulations, gentle slope of antithetic faults controllinghydrocarbon accumulations, gentle slope of synthetic faults controlling hydrocarbonaccumulations, faults cutting through the uplifts controlling hydrocarbon accumulations,faults divide fan body in the recess controlling hydrocarbon accumulations, reverse faultscontrolling hydrocarbon accumulations.Studies suggest that different fault systems in this area have3mode controllinghydrocarbon accumulations, early extensional and interim tensile shearing faulting shelteringhydrocarbon accumulation; early extensional reverse faults control the distribution of primarytectonic reservoir, early extensional and interim tensile shearing and late reversal faultscontrol the distribution of secondary petroleum reservoirs, and there are two fault controllinghydrocarbon transportation and accumulation pattern, the first is early extensional faultcontrol self generation and self reservation hydrocarbon accumulation and upper sourcerocks and lower reservoirs hydrocarbon accumulation, the other is faults formed in long termcontrol lower source rocks and upper reservoirs.