油气藏烃类垂向微渗漏及近地表化探异常的油气地质意义  

Vertical Micro-migration of Hydrocarbons from Subsurface Reservoirs and Geological Significance in Near-surface Geochemical Exploration for Oil and Gas

作　　者：蒋涛[1] 赵克斌[1] 荣发准[1] 张恒启[2] 

机构地区：[1]中国石油化工股份有限公司石油勘探开发研究院无锡石油地质研究所,安徽无锡214151 [2]安徽省地质矿产勘查局地质实验研究所,安徽合肥230001

出　　处：《天然气地球科学》2011年第5期901-908,共8页Natural Gas Geoscience

基　　金：中国石化科研项目"已知区近地表地球化学勘探应用研究"资助

摘　　要：结合渤海湾盆地临南断块油气藏、塔里木盆地雅克拉凝析气藏等研究区石油地质资料,从油气藏成藏特征、化探异常空间分布规律入手,探讨烃类垂向微渗漏的方式及受控因素,研究化探异常与油气藏烃类垂向微渗漏的"成因"联系,分析和认识化探异常的油气地质意义。夏口断层在临南断块油气藏成藏系统中具备油气侧向运移"封堵"特征,而研究区化探异常则揭示了夏口断层(裂隙)具有油气纵向"渗漏通道"作用,由此表明夏口断层具备油气侧向运移相对"封堵"和油气纵向绝对"渗漏"的双重属性特征。雅克拉气藏区化探异常围绕着气藏构造高部位(化探指标低值区)呈环状形式分布于气藏边缘,表明气藏盖层明显控制了气藏烃类垂向微渗漏和化探异常的空间分布特征;重烃指标异常空间分布规律与气藏盖层封闭性的横向变化规律具有较为一致的对应关系,表明气藏盖层封闭性对油气重烃微渗漏的影响较甲烷微渗漏影响更为明显。2个研究区近地表化探异常特征与其对应的油气藏成藏特征、油气垂向微渗漏等存在极为密切的联系。In this paper, we discuss the genetic correlation between geochemical anomaly and vertical micromigration of hydrocarbons from the subsurface oil and gas reservoirs and its geological significance in petroleum geology by means of vertical migration modes and controlling factors, as well as oil and gas accumulation and geochemical anomaly distribution in the Linnan block oil and gas field in the Bohai Bay basin and the Yakela condensate gas field in the Tarim basin. According to geochemical anomaly distribution, Xiakou fault in the Linnan oil and gas accumulation system act as a barrier for lateral migration of oil and gas but a vertical pathway in the study area,indicating that Xiakou fault plays a role of both relative barrier to lateral migration and absolute pathway to vertical migration. Geochemical anomaly has been distributed as a halo shape around the structural high point of Yakela gas field, suggesting that the gas seal would control vertical migration and space distribution of geochemical anomaly. Distribution of the heavier anomaly is consistent with lateral variation of sealing of caprock,indicating that the sealing of caprock to heavier hydrocarbons is more than that to methane. In two cases, we find out that the near-surface geochemical anomaly is related with oil and gas accumulation and vertical oil and gas micro-migration.

关 键 词：化探 异常 油气地质意义 微渗漏 油气藏 

分 类 号：TE132.4[石油与天然气工程—油气勘探]