Abstract: Sanmenxia Basin is a Mesozoic-Cenozoic fault basin located on the western Henan uplift in the southern margin of the North China block. No petroleum resources and effective source rocks were discovered during previous exploration activities. In recent years, non-profit oil and gas surveys have confirmed the presence of the Paleogene source rocks in the southern margin of the basin and have gained new insights into oil and gas accumulation. To verify the hydrocarbon potential of the basin, Well Yuxiadi 1 was drilled at Hanguguan structural belt. Drilling data of Paleogene Xiao’an Formation reveal that the porosity ranges from 13.43 % to 20.60 %, and the permeability varies from 35.1 mD to 215.5 mD. The drill stem test (DST) results of the lower oil layer of Xiaoan Formation demonstrate a wellhead oil production of 17.52 m³ under 24-hour intermittent flow conditions (water-free). Through formation testing by layer, combined with mechanical pumping production, the upper, middle, and lower oil layers of Xiaoan Formation have achieved the stable daily oil production of 4.79 m³, 6.79 m³, and 15.83 m³ (water-free), respectively. These results indicate that the Hanguguan structural belt develops the water-free wax-bearing light oil reservoirs characterized with medium-high temperature, medium porosity, medium permeability, medium-shallow depth, and normal pressure. A comprehensive research shows that the oil source of Well Yuxiadi 1 may be derived from the lower Member of Xiaoan Formation and the upper Member of Podi Formation, the mudstone in Liulinhe Formation and its overlying strata serve as regional cap rocks, and normal faults act as the primary hydrocarbon transportation system. Sanmenxia Basin develops four sets of potential source-reservoir-cap assemblages, and it is inferred that its hydrocarbons have the characteristics of "short-distance migration, multiple hydrocarbon accumulation types, and forming reservoir in late stage", and the main accumulation stage is in the Himalayan period. The oil and gas breakthrough in Sanmenxia Basin signifies the emergence of a new petroliferous basin, which is expected to re-attract attention from the industry on medium- to small-sized basins, such as Southern North China Basin and Weihe Basin. This is of certain reference value and guiding significance to the exploration of oil and gas resources in these basins.

Key words: Sanmenxia Basin, Hanguguan structural belt, Well Yuxiadi 1, Cenozoic, oil-gas exploration breakthrough

摘要： 三门峡盆地为华北陆块南缘豫西隆起上的中生界—新生界断陷盆地,以往的勘探没有发现油气和有效烃源岩。近年来,公益性油气调查在盆地南缘落实了古近系烃源岩并取得了一些油气成藏新认识。为查验盆地的含油气性,优选函谷关构造带,实施钻探了豫峡地1井。该井揭示古近系小安组油层的孔隙度为13.43%~20.60%,渗透率为35.1~215.5 mD。小安组下部油层组钻杆地层测试结果显示,间喷24 h条件下的井口产油量为17.52 m³(不含水)。采用分层试油,机抽求产,小安组上部、中部和下部油层组的稳定产油量分别为4.79 m³/d、6.79 m³/d和15.83 m³/d (不含水),表明函谷关构造带发育中—高温、含蜡、中孔中渗、不含水、中—浅层、常压、轻质油藏。综合研究表明,豫峡地1井的油源可能为小安组下段和坡底组上段烃源岩,柳林河组及上覆地层中的泥岩为区域性盖层,正断裂是油气的主要输导体系。三门峡盆地发育4套可能的生-储-盖组合,推断其油气具有“短距运聚、多类型聚集、晚期成藏”的特点,主要成藏期在喜马拉雅期。三门峡盆地的油气突破预示着一个新的含油气盆地诞生,将唤起业内对中—小型盆地油气资源的新关注,对久攻未克的南华北盆地和渭河盆地等中—小型盆地的油气勘查具有借鉴和指导意义。

关键词: 三门峡盆地, 函谷关构造带, 豫峡地1井, 新生界, 油气突破