Tanan Depression Fault Growth Deformation Mechanism And The Controlling Hydrocarbon

Based on interpretation of 3-D seismic data, Tanan depression is divided into 3 basins vertically, from bottom to up as follows:interment-basin whichi formed in Tongbomiao group, passive rift in Nanyiduan and naner member, active rift in the period of from nansan member to qing yuan gang group.the active rift can be divided into 3 major tectonic statas: fault depression strata in Nansan member and Nansi member, rift-depression strata in Dayi member and Daer member; depression strata in qingyuangang group.Tanan depression is duplex half graben-rift which is composed of 4 different types of basins. Each type of basin has its own period of structural styles, strike-slip activity resulted in a large number of antithetic faults in passive rifting period; these was a large scale "the central anticline belt" in active rifting period;the faults structural style looked like flower shape in rift-depression period; the fracture showed inverted structural styles by the compressive stress in the basin of inversion.Tanan depression mainly developed two transformation zone and nine hard-linkage transformation zone.Using "three diagram and a stripped picture" to interpretate evolution of the different kinds of transformation zone,we draw a conclusion that transformation zone mainly developed in Naner member and Nansan member and controlled the distribution of sandbody.Different kinds of basin tectonic styles composed different characteristic basins:mountain residue basin in Tongbomiao group,basin in passive rifting period, small multiple faulted basin in active rifting period.There were two sets of hydrocarbon source rock in Naner and Nansan member. Hydrocarbon source rock of Naner member was the main hydrocarbon source rock. Hydrocarbon source rock of Nansan member was the important hydrocarbon source rock. Regional strike-slip activity resulted in antithetic faults which caused the strata upward,the strata because of long-term eluviation of atmosphere and water become favourable store rock.According to the formation and evolution of Tanan depression, the fracture can be divided into four sets of fault systems:early extensional fault system, medium trans-tensional fault system, early-extensional mid-transtensional fault system, early-extensional mid-transtensional late-reversal fault system. Early extensional fault system and early-extensional mid-transtensional fault system prevented hydrocarbone from losing in Naner member and Nanyi member.the early-extensional mid-transtensional late-reversal fault system played a part of bridge and link for hydrocarbone storage,made the underneath hydrocarbone migrate to formate reservoir in Nansi member and Daer member.Fractures of poor-controlling model in Tanan depression can be divided into three types:the model of hydrocarbone lateral migration and antithetic faults hiding and lower uplift accumulating,the model of hydrocarbone primary migration and synthetic faults sealing or lithologic pinch out accumulating in groove, the model of hydrocarbone vertical migration and reversal faults conducting and reversal fractures accumulating.