南海西部海域断陷湖盆油气聚集规律及勘探前景  

Hydrocarbon accumulation regularity and exploration prospects of fault lacustrine basins in western South China Sea

作　　者：李绪深 甘军 张迎朝 张建新 杨希冰 邓勇 徐新德 吴杨瑜 

机构地区：[1]中海石油(中国)有限公司湛江分公司,广东湛江524057

出　　处：《中国海上油气》2015年第4期22-29,共8页China Offshore Oil and Gas

基　　金："十二五"国家科技重大专项"大型油气田及煤层气开发(编号:2011ZX05023-001-007)"部分研究成果

摘　　要：运用构造地质学、沉积学、古湖泊学及成藏综合分析等技术方法,深入分析了南海西部海域北部湾盆地和珠江口盆地珠三坳陷的构造演化特征、古湖泊背景与烃源岩发育特征、古近系沉积充填特征与大型储集体分布模式以及油气聚集规律和勘探前景。结果表明:1北部湾盆地涠西南、乌石凹陷及珠三坳陷文昌凹陷始新统湖相烃源岩分布广、规模大,富藻有机质输入的优质烃源岩发育,为油气生成奠定了雄厚的物质基础;2南海西部海域断陷湖盆古近纪湖水升降频繁,形成了低位域坡折带控砂、高位域源区控砂、陡坡带断层转换带控砂和缓坡带浪基面控砂等4种控砂模式,并且各控砂模式下的大型储集体时空展布、沉积相类型及物性特征差异明显;3南海西部海域断陷湖盆具备"一源多储、断脊运移、立体富集"的油气聚集规律,形成了凹中隆、斜坡、凸起等3个有利运聚单元及相应的3种成藏模式;4涠西南凹陷东斜坡、乌石凹陷北坡及文昌A凹陷北坡的古近系构造圈闭和隐蔽圈闭是南海西部海域断陷湖盆剩余勘探潜力较大的新领域。The characteristics of tectonic evolution, paleolacustrine source rock, Paleogene sedimentary fill- ing and large reservoir distribution mode, hydrocarbon accumulation regularity and exploration prospect in Beibuwan basin and Zhu-Ⅲ depression, Pearl River Mouth basin were studied by synthetically applying structural geology, sedimentology, paleolimnology and comprehensive accumulation analysis. It is concluded that： ① the Eocene lacustrine source rocks in Weixinan, Wushi sags of Beibuwan basin and Wenchang sag of Zhu-Ⅲ depression distribute widely with large scale volume. The high quality source rocks with rich algae provide a strong material basis for oil and gas generation. ② frequent variation of water level in Pa- leogene lacustrine fault basin contributes to forming four kinds of sand-controlling modes： slope break belt in lowstand system tract, clastics provenance area in highstand system tract, fault conversion zone in steep slope and wave base in gentle slope, and the space-time distribution characteristics of large reservoir, sedi- mentary facies types and physical properties of the four sand-controlling modes differ significantly. ③ fault lacustrine basins have an oil and gas accumulation regularity of ＂a source with multiple reservoirs, migralion along fauh ridge and three-dimensional enrichment＂, which forms lhree advantage migration units： in ner-sag uplift, slope and uplift, and three corresponding petroleum accumulation modes. ④ slruclurai and subtle traps in Paleogene in east slope of Weixinan sag, north slope of Wenchang A sag and north slope of Wushi sag are new and potential domains for remaining petroleum exploration.

关 键 词：南海西部海域 断陷湖盆 构造演化 烃源岩 大型储集体分布 油气聚集规律 勘探前景 

分 类 号：TE122.33[石油与天然气工程—油气勘探]