东海盆地西湖凹陷孔雀亭气区气侵条件及主控因素  

Geologic Conditions and Main Controlling Factors of Gas Washing in Kongqueting Region in Xihu Depression,Eastern Sea Basin

作　　者：苏奥[1,2] 陈红汉[2] 马玉华[3] 詹海勇[3] 杨文帅 

机构地区：[1]中国石油东方地球物理公司研究院,河北涿州072750 [2]中国地质大学(武汉)构造与油气资源教育部重点实验室,湖北武汉430074 [3]中国石油新疆油田分公司石西油田作业区,新疆克拉玛依834000 [4]中国石油寰球工程项目管理(北京)有限公司,北京100027

出　　处：《天然气地球科学》2015年第2期292-300,共9页Natural Gas Geoscience

基　　金："十二五"国家重大科技专项"中国近海新生代盆地演化及油气富集机理"(编号:2011ZX05023-004-010)资助

摘　　要：西湖凹陷曾发生过大规模的气侵分馏作用,但目前仅局限于定性描述。以平湖构造带孔雀亭气区为研究对象,利用流体包裹体和原油正构烷烃测试等手段,结合该区油气地球化学性质和断裂构造特征,研究了孔雀亭气区气侵条件及主控因素,并讨论了气侵分馏作用对油气藏的影响。结果表明,该区高有机质丰度、生气持续的煤系源岩提供了充足气源,数量众多的断裂发育以及油气充注时间的良好匹配等地质条件,使得孔雀亭气区能够大规模发生气侵分馏作用。气侵分馏定量计算表明研究区各井原油的正构烷烃损失率Q值介于35.3%~97.1%之间,折点碳数介于18~27之间。气源距离和垂向深度共同控制了气侵分馏的强度,而且前者比后者表现出更强力的控制。气侵分馏不仅使得孔雀亭气区各井沿着气侵方向其含气层数和凝析气层数比值逐渐减小,而且导致该区呈现出＂上油下气＂的垂向分布样式以及低蜡质凝析油与伴生的高蜡质油等复杂原油类型的形成。There was extensive evaporative fractionation effect in Xihu Depression, Eastern Sea Basin. However, most of the previous study on the gas washing is qualitative description. Taking Kongqueting region in Pinghu structural belt as an example, based on the geochemical characteristics and fracture characteristic, this paper dis- cussed geologic conditions and main contrOlling factors of gas washing and analyzed effect of hydrocarbon reservoir by fluid inclusion system analysis technology and n-alkanes testing method. These findings suggest that coal meas- ures which can generate gas continuously have abundant organic matter and provide good source rocks. Numerous faults and good match between oil and gas filling time result in the occurrence of gas washing in the Kongqueting region. Quantitative calculation of gas washing fractionation effect show that n-alkane loss rate of crude oil in the wells in the study area is 35.3% to 97.1% and break number is 18 to 27. Source distance and vertical depth control strength of gas washing fractionation effect. Besides,the former is more powerful controlling function than the lat- ter. Gas washing fractionation effect not only makes gas layers and ratio of condensate gas layers decrease along the direction of the gas invasion,but also leads to the pattern of oil reservoir above gas reservoir and formation of con- densate with low wax content and condensate gas with high wax content.

关 键 词：气侵 条件 主控因素 西湖凹陷 孔雀亭气区 

分 类 号：TE122.1[石油与天然气工程—油气勘探]