“油气运移动态富集”概念及其在塔里木台盆区油气勘探中的应用

The concept of “petroleum migration and dynamic accumulation” and its application in petroleum exploration in cratonic area, Tarim basin

“油气运移动态富集”概念及其在塔里木台盆区油气勘探中的应用[刊]/周东延,李洪辉∥石油勘探与开发.2000,27(1).2～6,11提出“油气运移动态富集”概念,用初次富集、二次富集和再次富集描述动态充注条件,分4个层次研究。塔里木台盆区(塔中隆起、塔北隆起和巴楚隆起)特殊石油地质问题要点是:①控制古生界烃源岩品质、生烃母质丰度的因素是有利沉积相带分布;②存在古隆起发育事件、深埋事件和热事件,导致寒武系—奥陶系有效烃源岩局限于一些特定地区,须从烃源岩动态演化的角度分析油源条件。③沉积、构造多旋回规律性迁移造成多含油气系统叠合。塔中地区可划分4个运聚成藏阶段:①中奥陶世—早志留世下构造层形成自生自储内幕原生油气藏与破坏散失并存阶段,油气动态富集明显受古隆起控制;②中志留世—二叠纪再次运移形成沥青砂为主阶段,隆起西部倾没端是有利运聚成藏区带;③二叠纪—第三纪运聚充注成藏为主阶段,塔中10构造带和塔中1号断裂构造带是有利运聚成藏区带,主分隔槽(北翼鼻隆与中央断垒交汇带)以南因无油源条件而无成藏条件;④晚第三纪以来油气藏调整为主阶段。塔中地区下构造层关键评价要素是古油气藏保存条件和有无晚期油气补充条件,特别应注意位于有利油气汇聚区的岩性圈闭。提出塔中地区勘探?

The concept of “petroleum migration and dynamic accumulation” is proposed. The dynamic charging condition is characterized by first and secondary accumulation, and the research is proceeded on four levels. The major features of the particular petroleum geology conditions in cratonic areas of Tarim basin include: ①The distribution of favourable sedimentary facies belt controls the quality of Paleozoic source and percentage of petroleum generating organic matters. ②There were paleouplifting, deep burial, heating events, which lead to the limited distribution of Cambrian and Ordovician effective source in particular areas. So the petroleum source must be determined according to the dynamic evolution of the source rock. ③The regular migration of multi cycle tectonism and deposition results in the superposition of petroleum systems. Four migration and accumulation stages can be identified: ①Original pool with source and reservoir in the same formation and pool destroying and leaking exist at the same time in the lower tectonic section in middle Ordovician early Silurian. The hydrocarbon dynamic accumulation apparently is controlled by paleo uplifts. ②The tar sands resulted from secondary hydrocarbon migration in middle Silurian Permian. The western plunging end of the uplift is of favorable migration and accumulation. ③Migratory concentration and pool generation dominated during Permian Tertiary. Tazhong 10 and Tazhong 1 fault zones are of favorable migration and accumulation. South to the primary separator valley (the interlaced zone of north nose like uplift and center host) is not of pool forming due to the lack of hydrocarbon source. ④The modification of pools dominated since Neogene. The key contributors to evaluation for the lower structural section in Tazhong area are maintenance of paleo pools and later charging of hydrocarbon, especially the lithological traps within favorable accumulation area. Some exploratory and planing suggestions about Tazhong are provided, and it is believed that a research system and exploratory mode based on “dynamic” idea from start to end should be established.