Fault Structural Characteristics Of Wen’an Slope In Jizhong Depression And Their Reservoir-Controlling Mechanism

Based on studying the geometry characteristics of the fault, this paper analyses the evolution and formation of faults, the fracture deformation of the Wen’an Slope experiences three stages: the extensional deformation of Ek to Es3、the strike-slip extensional deformation of Es1+2 to Ed and the strike-slip deformation after the Nm1.Based on the fault deformation three stages and deformation character, the Wen’an Slope can divide into six sets of fault systems: the early extensional fault(I type), the middle extending extending strike-slip fault(II type), the late strike-slip fault(III type), the early extensional-middle extending strike-slip fault(IV type), the middle extending strike-slip-late strike-slip fault(V type), the early extensional-middle extending strike-slip-late strike-slip fault(VI type).Base on the T3 target layer mainly develop IV type、V type and VI type fault systems.The accumulation period active IV type, V type and VI type fault systems accumulation period communicate source rocks and reservoir, that calls oil-source fault, this type fault can conduct oil and gas. As a result of the slope outside the study area is the source, thus the accumulation period active III type, V type and VI type fault systems are mainly for conducting fault.Two sets of mudstone cap rock in the study area, the lower of Es1 and the upper of Es1 mudstone cap rock, the oil and gas in the lower part of mudstone cap rock enrichment in breakout thickness is greater than the limit of thickness of the breakout of mudstone cap rock strata. In addition, fracture density area are also oil and gas enrichment region, and the oil and gas enrichment degree depends on the fault lateral seal ability, migration along the fracture of the enrichment of oil and gas to SGRmin low horizon. The Wen’an Slope is upper source and lower reservoirs, the lower oil-gas along priority the fault "convex section ridge" the advantage of conducting channels for vertical migration. And slope is an outside source, mainly the lateral migration of oil and gas, and sand body development in the study area, so when the lateral migration of oil and gas in conducting match the sand body, fault occurs across the layer to adjust migration. Late break in the activity again, the lower part of the communication system of oil and gas activity again type V type, VI type, and a part of III type fault systems can make the oil and gas adjust the migration.