摘要
为了揭示正断裂在油气成藏中的作用,通过对正断裂向上和向下输导运聚油气与受其控制所形成油气藏之间关系的研究,探讨了正断裂向上和向下运聚油气作用的差异性。结果表明正断裂向上和向下运聚油气作用的差异性主要表现在以下3个方面:1二者输导油气动力和条件不同,前者输导油气动力是剩余压力差和浮力,条件是剩余压力差和浮力之和大于断层岩毛细管力;后者输导油气主要动力是超压,条件是超压大于断层岩毛细管力、浮力和地层压力差之和。2二者输导油气距离和影响因素不同,前者输导油气距离通常大于后者输导油气距离,前者主要受到距区域性盖层距离的影响,距区域性盖层的距离越大,输导油气距离越大;反之则越小。后者主要受到超压大小的影响,超压越大,输导油气距离越大;反之则越小。3二者油气富集部位不同,前者油气纵向上主要富集在区域性盖层上下附近,平面上油气主要富集在输导正断裂的上盘;后者油气纵向上主要富集在源岩附近,平面上油气主要富集在输导正断裂的下盘。
To reveal the role of normal faults in oil and gas accumulation, the differences between upward and downward transporting of oil and gas through normal faults are studied based on the research of the re- lationship between the transporting rule and the reservoirs formed under its controlling effect. Differences in three aspects are found in upward and downward migration and accumulation of oil and gas through nor- mal faults. Firstly,the dynamic and condition of oil and gas transportation are different. Upward oil and gas transportation is driven by residual pressure difference and buoyancy. When the driving force is greater than the resistance formed by capillary force of fault rocks, oil and gas will be transported upward through the fault. Whereas,the downward oil and gas transportation is mainly driven by overpressure. When over- pressure is greater than the total add-up of capillary force of fault rocks, buoyancy and formation pressure difference, oil and gas will be transported downward through the normal fault. Secondly, the oil and gas transporting distance and influential factors are different. Generally,the distance of upward transportation of oil and gas is longer than that of downward transportation. The former is under the influence of distance to regional cap rocks. The longer distance, the further oil and gas will be transported and vice versa. The latter is under the influence of overpressure. The bigger the overpressure, the further the oil and gas will be transported and vice versa. Finally, oil and gas accumulated in different positions. The oil and gas transpor- ted upwards. Vertically, the oil and gas usually accumulated near the top and bottom of regional cap rocks, and horizontally, they distributed around the hanging side of normal fault through which oil and gas trans- ports. While the downward transporting oil and gas accumulated vertically near the source rocks and hori- zontally at the footwall of normal fault.
出处
《天然气地球科学》
EI
CAS
CSCD
北大核心
2014年第8期1210-1217,共8页
Natural Gas Geoscience
基金
国家自然科学基金项目"油源正断裂转换带优势输导运移油气条件研究"(编号:41372153)资助
关键词
正断裂输导
向上运移
向下运移
差异性
Normal fault transportation
Upward migration
Downward migration
Differences
