岔路河断陷万昌—梁家构造带万昌组沉积相和油气成藏特征

Sedimentary facies and reservoir characteristics of Wanchang Formation in Wanchang——Liangjia structural belt of Chaluhe faulted depression

万昌构造带和梁家构造带是岔路河断陷的两个重要油气聚集带,在形成演化过程中,万昌构造带受到东南缘控盆断裂的控制,而梁家构造带受Ⅱ号断层的控制,导致了砂体的沉积相差异。岩心、测井和地震资料研究表明,浅层万昌组地层中,万昌构造带主要发育扇三角洲砂体,梁家构造带主要发育水下扇砂体,砂体的连续性和储集物性较好,尤其是离物源较近的分流河道和辫状沟道砂体的孔渗较高,深层双阳组、奢岭组、永吉组发育较好的烃源岩,控盆断裂及其衍生的一系列断层有助于油气的运移和封闭,油气成藏条件较好。

Wanchang and Liangjia structural belts are the important hydrocarbon accumulation zones in Chalu- he faulted depression, controlled by different structures in the process of formation and evolution. The Wanchang structural belt is controlled by the basin-controlled fauh in southeastern margin, controlled by the No. 2 fault, which led to different sand facies. According to while the Liangjia structural belt is drilling core, well-logging and seis- mic data, the fan delta in Wanehang structural belt and underwater fan deposits in Liangjia structural belt are the domain sandstone sediments in shallow Wanchang Formation. The continuity and physical property of sand bodies in Wanchang Formation are good, especially, the distributary channel and braided channel sand near to provenance have higher porosity and permeability. The source rocks are well developed in Shuangyang-, Sheling- and Yongji formations. Basin-controlled faults and their derivative faults help the hydrocarbon migration and sealing. There- fore, the hydrocarbon accumulation are great in conditions.