南苏门答腊盆地B区块层序地层格架及有利成藏带

南苏门答腊盆地是新生代弧后裂谷沉积盆地,经历了4个构造演化阶段和1次完整的海进-海退旋回。形成了独特的层序地层充填和沉积体分布模式,发育湖泊、河流、三角洲、浅海陆棚碳酸盐岩及生物礁等多种沉积体系。建立了B区块的层序地层格架,将新生代地层划分为8个三级层序,SQ1—SQ4是主要勘探目的层段。根据古地貌特征,B区块划分为4个构造单元,各构造单元具有不同的沉积特征和勘探目标。纵向上总结了盆地各构造演化阶段,层序格架内发育4套成藏组合。平面上对各期层序构造解释后,应用构造叠合方法,综合分析各成藏要素,全区共划分出5个有利构造带,指出了各构造带的有利因素和勘探潜力,为下一步区块勘探选取钻探目标和落实储量规模提供了指导意义。

Sequence stratigraphic framework and play fairways in Block B of the South Sumatra Basin

South Sumatra Basin is a Cenozoic back-arc rift basin experienced four tectonic evolution stages and a full cycle of transgression-regression.As a result,the basin presents a unique sequence stratigraphy and sedimentray filling pattern and contains diversified depositional systems:lacustrine,fluvial,delta,shallow marine shelf carbonates,organic reef and etc.The Block B in the basin was studied in detail and its sequence stratigraphic framework was established.The Cenozoic strata in the block were divided into eight third-order sequences with Sq1 to Sq4 as the key exploration targets.Based on its paleo-geomorphic characteristics,four structural units with different sedimentary characteristics and exploration target were identified.Vertically,four plays were identified within the sequence stratigraphic framework based on summation of each structural evolution stage.Laterally,the hydrocarbon accumulation conditions were comprehensively analyzed by using structure overlapping method after structure interpretation of each stage,leading to the identification of five prospective structural zones.The study offers a sound foundation for further exploration and development of the block.