苏门答腊裂谷盆地带构造分带及其成藏模式

苏门答腊弧后裂谷盆地带是印尼乃至东南亚最大的油气产区，由于勘探程度高, 近十年来勘探成效差，盆地油气发现进入瓶颈期。为了指明苏门答腊弧后裂谷盆地带勘探方向，以盆地带构造演化为主线，以构造带为研究对象，在构造特征、构造对成藏模式控制作用等多方面研究的基础上，预测了苏门答腊盆地带有利勘探领域。根据构造特征分析，苏门答腊弧后裂谷盆地带可划分为近岛弧带、中央反转带和远岛弧带3个构造带。近岛弧带以继承性隆起为构造特征，油气主要通过断裂垂向运移，聚集在局部构造高部位生物礁和背斜之中，近岛弧带为旁生侧储型成藏模式，基底潜山圈闭是近岛弧带未来的勘探方向；中央反转带构造样式为挤压反转的半地堑、铲式正断层，中央反转带油气来自底部深凹陷，上部多层系做储层，垂向断层或侧向砂体发育，沟通烃源岩与圈闭，具有近水楼台的优势成藏条件，为下生上储型成藏模式，该带基底潜山圈闭和源内构造—岩性圈闭也具有较好的烃—运—储匹配关系，可能形成好的油气藏；远岛弧带以单斜构造背景为主，局部发育深洼陷，远岛弧带局部洼陷具有一定的生烃能力，该构造带钻井揭示了地层超覆油气藏，但目前勘探程度较低，尚存在较大勘探潜力。

STRUCTURAL ZONATION AND HYDROCARBON ACCUMULATION MODEL OF THE SUMATRA BACK ARC RIFT BASIN

The Sumatra back-arc rift basin is the largest oil and gas producing province in Indonesia and Southeast Asia. Since the exploration degree of the region is quite high already, new exploration results are pretty rare in the past ten years, and thus the hydrocarbon discovery in the basin has entered a bottleneck. In order to find out the target areas for future exploration in the basin, we studied the tectonic pattern of the basin and its control over the distribution of source rocks and reservoirs. Upon the basis, the future exploration direction of the back arc rift basin is discussed. According to tectonic features, the Sumatra back-arc rift basin can be subdivided into three structural belts namely the near island arc belt, the central inversion belt and the distant island arc belt. The near island arc belt, in fact, is an inherited uplift. Oil and gas migrate vertically mainly through faults and accumulate in high-stand traps such as reefs and anticlines. The buried-hill trap is the major exploration target for future in the belt. The central inversion belt is dominated by semi-grabens and shovel-like normal faults. Oil and gas come from deep depressions and accumulated in the multi-layer reservoir in the upper part. Both fault and sand body act as the pathway for oil and gas migration. Buried-hill and structural-lithological are the main traps for hydrocarbon accumulation. The distant island arc belt is dominated by monoclinic strata locally with visible depressions which have hydrocarbon generation potential. Lithological hydrocarbon reservoirs occur in the belt and there is a great potential for future hydrocarbon exploration.