Differences of lateral sealing ability between consequent fault and antithetic fault in Wen'an slope
To reveal the controlling effect of faults on hydrocarbon accumulation and distribution in petroliferous basin,taking the Wen'an slope of Jizhong Depression as the target area.Based on the differences in hydrocarbon accumulation site and scale between consequent faults and antithetic faults,then combing the characteristics of the surrounding rock which slide into the fault zone and the asymmetry of the internal structure of the fault zone,finally analysis the differences between clay content(SGR),risk displacement and their effects on lateral sealing in different configuration types of faults.The result indicated that:1)in the case of similar sedimentary environment,when the fault displacement is less than the thickness of single sand-mudstone layer and the fault displacement is odd times of the thickness of single sand-mudstone layer,the clay content of the target point of the antithetic fault is significantly higher than that of the consequent fault;when the fault displacement is even times of the thickness of the single sand-mudstone layer,the clay content of the target point of the antithetic fault is equal to that of the consequent fault.The clay content which sliding through the target point of antithetic fault is significantly more than that of the consequent fault,the average value of SGR of antithetic faults is 6％higher than that of consequent faults in Es,layer of Wen'an slope.2)To seal the thicker damage zone in hanging wall,the critical displacement required for the consequent fault is significantly larger than that of the antithetic fault,and the average risk displacement of consequent fault is about 1.8 times as large as that of antithetic fault in Wen'an slope.3)Theoretical and case analysis confirmed that:the antithetic faults are more likely to form lateral seal,which is consistent with oil and gas mainly accumulated near the antithetic fault.However,in the Wen'an slope,and the fault displacement is even times of the thickness of single sand-mudstone layer,so that the clay content of fault rock is approximately equal,which may be the main reason for the nearly consistent height of hydrocarbon columns sealed by both consequent and antithetic faults in the Wen'an slope.The above conclusions can provide favorable guidance for the exploration and development of oil and gas fields.
国家科技期刊平台
NSTL
万方数据
