作　　者： ; ; ; ;

机构地区： 中山大学海洋学院

出　　处： 《天然气工业》 2009年第11期9-12,共4页

摘　　要： 已有的油气勘探成果表明,南海北部陆缘东部与西部的油气运聚特征具有很大的差异。通过总结前人对东、西部油气运聚规律的成果和认识,以东部的珠江口盆地与西部的莺—琼盆地为例,分析对比了东、西部油气运聚模式的差异性。东部表现为:油气垂向运移与侧向运移相互配合,动力为水动力及浮力,后期断层的活动性对油气运聚成藏起关键作用;西部表现为:底辟带作为油气垂向运移的主要通道,不整合面以及砂岩疏导层作为油气侧向运移通道,主要驱动力为高压活动流体;流体底辟和后期断层的活动性分别对天然气的聚集和保存起关键作用。通过油气运聚差异性的对比分析,结合南海北部陆缘的沉积特征以及构造运动背景分析,结论认为:这种差异性实质就是运聚过程中环境的差异,即东部为常压环境,西部为超压环境,形成原因是北部陆缘东部珠江口盆地受东沙运动影响,发育的一系列张扭性NW向断裂对超压层系起卸压作用,西部受东沙运动影响弱而容易形成超压环境。 The existing petroleum exploration results reveal that the eastern and western segments of the northern margin of the South China Sea are significantly different in the characteristics of hydrocarbon migration and accumulation.Based on summarizing the previous achievements and understandings,we analyzed the differences in the patterns of hydrocarbon migration and accumulation between the eastern part represented by the Pearl River Mouth Basin and and the western part by the Yinggehai-Qiongdongnan(Yingqiong)Basin.In the eastern part,hydrocarbons migrate both vertically and laterally under the joint driving of hydrodynamic force and buoyancy,and the activity of late faults plays a key role in hydrocarbon migration and accumulation.While in the western part,hydrocarbons migrate vertically along diapire zone(the main pathway)and laterally along the unconformities and sandstone carrier beds mainly under the driving of high-pressure active fluids.The diapires and late fault activity play a key role in gas accumulation and migration respectively.A comparative analysis of the differences in hydrocarbon migration and accumulation,in combination with the study of the sedimentary features and tectonic movement,reveals that the difference in environments is the main cause.The eastern part has normal pressure as because the NW-trending transtensional faults resulted from the Dongsha movement can release the overpressure.In contrast,the western part shows overpressure due to the weak influences of the Dongsha movement.

关 键 词： 南海北部陆缘 油气运聚 特征 成藏规律 珠江口盆地 莺琼盆地 超压环境 差异

领　　域： [天文地球] [天文地球] [天文地球] [天文地球]