印度尼西亚西纳土纳盆地油气地质特征与分布规律

GEOLOGICAL CHARACTERISTICS AND DISTRIBUTION PATTERN OF PETROLEUM IN WEST NATUNA BASIN,INDONESIA

西纳土纳盆地是发育在东南亚巽他克拉通内的裂谷盆地,也是印度尼西亚重要的含油气盆地。运用盆地分析及石油地质学的理论与方法,对盆地构造—沉积演化及主力烃源岩、储集层及盖层等成藏要素进行综合研究,系统总结油气成藏特征及分布规律,并通过对比分析指出构造演化与沉积充填差异是造成盆地内烃源岩演化、储集层发育、油气成藏特征差异的主控因素。研究表明,油气可采储量区域上集中在Anambas地堑和Penyu次盆东北部,主要油气田(藏)类型包括挤压背斜、披覆构造和地层—构造型;层系上,油气主要储集于上渐新统和下中新统。盆地内远景地层圈闭以上始新统—下渐新统Belut组冲积扇相砂砾岩和上渐新统—下中新统Gabus—下Arang组河流下切谷砂岩为有利储层,勘探程度低,资源潜力较大。

The West Natuna Basin,an intracratonic rifted basin on the northern Sunda Shelf,is an important petroliferous basin in Indonesia.Following the principles of basin analysis and petroleum geology,taking the tectonic evolution and sedimentary filling history of the whole basin as the major theme,we studied in this paper the forming mechanism of petroleum accumulation,such as source rocks,reservoirs and seals,in the basin.The hydrocarbon distribution and accumulation patterns were systematically summarized.Through comparison,it is concluded that the difference of tectonic evolution and sedimentary filling is the controlling factor over the difference in source maturity,reservoirs and hydrocarbon accumulation characteristics in the basin.Regionally,the discovered oil and gas reserves are largely confined to the Anambas Graben and the Northeastern Penyu Sub-basin and trapped in compressional anticlines,draping structures and structure-stratigraphic traps.Stratigraphically,the oil and gas are mostly reserved in the Upper Oligocene and Lower Miocene.Future exploration potential may exist in the under explored stratigraphic traps in the coarse grained alluvial fan deposits of the Belut Formation and incised valley fills of the Gabus Formation and Lower Arang Formation.