鄂尔多斯盆地延长探区油气勘探理论与实践进展

陕西延长石油（集团）有限责任公司在鄂尔多斯盆地坚持深化精细勘探常规油气藏，积极探索非常规油气，揭示了低渗混合润湿孔隙介质通道中石油推进式运移的动力学条件与机理，创建了特低渗交替式石油成藏理论，厘清了油藏控制因素及富集规律，指明了老油区勘探方向。在天然气勘探方面，揭示了上古生界砂体及裂缝输导、多期充注、原地或垂向运聚的成藏机理，其具有“广覆式”生烃、“大面积”成藏、储集砂体垂向叠置横向连片、近距离运移多层段聚集的特点；下古生界古地貌环境、储层岩溶及成岩作用、运移动力、铝土岩不整合输导体等因素控制了奥陶系马家沟组天然气聚集成藏。形成了对页岩气成因类型、赋存空间、赋存顺序的多项认识，并通过配套使用针对低渗-特低渗油藏及页岩气、致密油等非常规油气领域的多项勘探工程技术，有力指导了油气勘探实践。

Advances in theory and practice of hydrocarbon exploration in Yanchang exploration area,Ordos Basin

Shaanxi Yanchang Petroleum (Group) Co., Ltd. persists in further precisely exploring conventional hydrocarbon reservoir in the Ordos Basin and has been actively exploring unconventional hydrocarbon resource there, thus revealing the dynamic conditions of and mechanism for advancing migration of oil in low permeability pathways mixed with wet porous media. On this basis, it has established an alternating oil accumulation theory for ultra-low permeability reservoirs, elucidates oil reservoir controlling factors and enrichment pattern, and points out exploration direction in old oil fields. In regard to natural gas, a hydrocarbon accumulation mechanism of Upper Paleozoic sandstone and crevice carrying, multiphase charging, as well as in-situ or vertical migration and accumulation is revealed, which is characterized by wide-coverage hydrocarbon generation, large-area hydrocarbon accumulation, vertically stacked and horizontally contiguous reservoir sand bodies, short-distance migration and multi-interval accumulation; natural gas accumulation in the Ordovician Majiagou Formation is controlled by such factors as Lower Paleozoic paleotopographic setting, reservoir karstification and diagenesis, migration driving force, and bauxite unconformity carrier. Furthermore, several understandings of shale gas genesis type, occurrence space and occurrence sequence are obtained, and then provide a powerful guidance for actual hydrocarbon exploration using the matched exploration engineering techniques for low-ultra-low permeability oil reservoir and unconventional hydrocarbon resource such as shale gas.