高邮凹陷真武地区地下水动力场与油气运聚

在深入研究地层水化学、地层压力及流体势分布特征基础上,结合研究区构造发育、沉积相分布特征,采用流体化学、动力学分析方法,将高邮凹陷许庄、真武和曹庄油田由南向北划分为大气水下渗向心流区、越流泄水区和泥岩压实排水离心流区3个局部水动力单元.压实流汇聚形成的越流泄水区及压实流与大气水下渗向心流汇合形成的越流泄水区有利于油气运移聚集,而以大气水下渗为主的地区,总体上不利于油气的保存和聚集.高邮凹陷许庄 真武 曹庄地区北部为烃源岩中心,发育泥岩压实排水离心流,油气在离心流运移路径中遇到合适圈闭,即可成藏；南部许庄地区为大气水下渗向心流区,断裂发育,地层开启性好,大气水沿断裂下渗,油气成藏条件较差；中部越流泄水区为北部泥岩压实排水离心流和南部大气水下渗向心流的共同指向区,是油气的有利聚集区,研究区已探明油田多数位于该越流泄水区.本研究有利于指导研究区的下一步油气勘探.

Properties of hydrodynamic field and the migration and accumulation of oil and gas in Zhenwu area of Gaoyou sag

Based on the characteristics of formation water hydrochemistry, formation pressure and fluid potential distribution, combining with the characteristics of tectonic development and sedimentary facies distribution, using fluid chemistry and dynamics analytical methods, Xuzhuang, Zhenwu and Caozhuang area in Gaoyou sag were divided into three hydrodynamic units from south to north: centripetal flow area of meteoric water down-permeating, cross-formational flow discharging area and centrifugal flow area of mudstone-compacted water. The cross-formational flow areas formed by mudstone compaction released water, and the one converged by centrifugal flow of mudstone compacted water and centripetal flow caused by meteoric water infiltration, are advantaged to hydrocarbon accumulation, while generally the meteoric water infiltration area is disadvantageous for oil and gas accumulation. Northern Xuzhuang Zhenwu Caozhuang area of Gaoyou sag is the center of hydrocarbon source rocks, developing centrifugal flow of mudstone compaction-released water, oil and gas may be accumulated into reservoirs along with this centrifugal flow if there are suitable traps; Centripetal flow area in southern Xuzhuang area develops many faults, resulting in a good opening formation, and meteoric water trickles down along the faults, and therefore, the hydrocarbon preservation conditions are poor here; Cross formational flow area of center part is a favorable oil and gas accumulation zone, which is the common point area of northern part mudstone compaction-released water and southern part meteoric water infiltration. Most explored oilfields are located in this area. The results of this study provide valuable insight guide for designing the exploration plan of the research area．