Review Of Rules Of Fault Controlling Putaohua Reservoir In Xujiaweizi Oilfield,Sanzhao Depression

Based on the comparative analysis of fault geometry characteristics of mudstone top surface(T11 reflective layer) and bottom surface(T2 reflective layer) in Qingshankou formation, Sanzhao Depression, the kinematics characteristics and genetic mechanism of fault had been systematically analyzed by the author. The author think that high density fault in T2 reflective layer is caused by tectonic genesis. Under EW extensional stress field in early Qingshankou formation, the bottom surface of plastic mudstone(T2 reflective layer) formed a number of fault concentrated belts with different extending orientation which is controlled by oblique rifting, differential extending, basement fault and caldera.Fault concentrated belts in T11 reflective layer which has the same distribution characteristics with the T2 fault system still developed. It indicates that when fault develop,T2 fault influenced more. The result was not a rupture between the simple inheritance growth,and the growth of the connected vertical segment results. Field observations, typical earthquake anatomy and physics simulations confirm, as long as the existence of competent rock is poor, fault has characteristics of typical vertical segmentation growth. Rock competent differences determine fault evolution through three stages: the formation of lower part of fault,breaking through the upper and lower fault segments and the formation of penetrating fault.After reinterpretation of syncline area fault in Xujiaweizi, using rock mechanics characteristics and fold theory related to fault, the author clear the characteristics of the fault vertical segments growth. Faults in T11 and T2 grow segmentally and has poor interconnection, but its development greatly influenced by T2 fault system, stress transition usually achieved by the rock bridge which is formed by two fault systems superposed. There are two typical ways of fault vertical superposition: restrictive superposition and releasing superposition. The main superposition type of T11 and T2 fault system in Sanzhao Depression is restrictive superposition. The strata in superposition part usually folded or rotated.Combined with fault geometry development and evolution characteristics, based on fault activity and connection with source reservoir, the author redefined the oil source faults in study area. Using production data from exploration appraisal well, anatomical analysis the Putaohua reservoir’s oil and water distribution rules and the relationship between it with fault,clear that how fault control the oil and water distribution. Oil and water distribution in study area is mainly controlled by fault concentrated belt, the oil is “strip” distributed on the horizontal which is controlled by antiform and “choosing layer” distributed on the vertical which is controlled by sedimentary sequence evolution and sedimentary sequence evolution.Oil wells are mainly located at the intersection of two faults in concentrated belts, but out of the belts, wells are also located at the intersection. In conclusion, the substance of concentrated belts controlling oil is the intersection control. Because of fault polyphase activity and insufficient supply from oil source, Songfangtun and Shengping oilfield in thenorth has vertical distribution pattern like “top oil, bottom water”.