川西龙门山前缘主要断层封堵性评价

EVALUATION ON THE SEALING PROPERTY OF MAJOR FAULTS IN THE FRONT LONGMEN MOUNTAIN,WEST SICHUAN BASIN

川西龙门山前缘地区是上三叠统的生烃中心,具有良好的生油气条件,油气圈闭保存条件对油气成藏显得尤为重要。川西龙门山前缘带发育多条断裂带,区内油气圈闭与断层发育密切相关,研究区主要断层的封堵性是油气成藏条件的重要方面,特别是影响制约了须家河组气藏的油气富集及保存条件。断层封堵性研究对于揭示该区的油气成藏机理及确定下一步的勘探方向具有重要意义。在对研究区主要断层发育及演化特征、断层封堵机理及其影响因素进行研究的基础上,重点对断层封堵性参数的计算方法进行了深入的分析,并结合研究区主要断层现有资料,对断面压力及断裂带填充物中泥质含量两个参数进行了计算,并编制程序绘制成图,对主要断层的封堵性进行了定量评价。结果表明,该区主要断层在须家河组地层具有良好的封堵性,能有效的封闭油气,有利于须家河组气藏的聚集与保存。

The front zone in the Longmen mountain is the centre for hydrocarbon generating in the Upper Triassic with good conditions,and the sealing property is essential for the generated hydrocarbon to be accumulated as good reservoirs.Within the study area,many oil and gas traps have been discovered there due to the developed fault zones.The sealing of faults is an important aspect of the pool-forming conditions,especially it affects the hydrocarbon enrichment and the reservation conditions of the hydrocarbon reservation in the Xujiahe group.The research on the sealing of the fault has great significance on revealing the mechanism of petroleum accumulation and further exploration.This paper analyzes the main faults' development and evolution characteristics,sealing fault mechanism and its influencing factors,especially on the method of calculating the parameters of the sealing of the faults.In addition,combined with the data available,it calculates two parameters including the pressure on fault plane and the shale content in the filler material of fault,programmes the composition,draws the graph and makes an evaluation on the sealing of the fault.The result shows that the main faults in this area have good sealing characteristics in the Xujiahe group and can seal the hydrocarbon effectively thus to be aggregated and preserved in reservoirs.