Abstract: The early exploration mainly focused on conventional hydrocarbon reservoirs in the middle-shallow positive tectonic zone in Tuha Basin. However, there is little research on explorations in new strata, new fields, and new types of oil-gas resources. In recent years, based on the synthetic research as well as gravity-magnetic-electrical method, seismic, drilling, and test data, a new round of efforts have been made on basin-level full-stratum fine structural interpretation, source rock evaluation, sedimentary and reservoir characterization, as well as investigations of hydrocarbon accumulation and enrichment regularities. The main understandings obtained are as follows. (1) The Tuha Basin underwent three tectonic movements of Hercynian-Indosinian, Yanshan, and Himalayan, by which basement faults, detachment faults, and piedmont thrust faults are developed, and have been controlling the distribution and uplift-depression pattern of different tectonic units in different periods. (2) The basin has developed four sets of source rocks with the Carboniferous marine and marine-continental transitional facies, Permian lacustrine facies, Triassic lacustrine facies, and Jurassic lacustrine facies/coal series, which have effectively enhanced the potential of oil-gas resources. (3) Three types of reservoirs are developed in the basin, i.e., Carboniferous carbonate rock, Permian-Jurassic clastic rock, and coal rock. (4) In addition to conventional oil and gas, new types of oil and gas such as tight sandstone oil and gas and deep coalbed methane are also detected in the basin. (5) Through comprehensive evaluation, six new exploration areas were selected, including Jurassic tight sandstone gas reservoirs, deep coalbed methane reservoirs, reservoirs in the large tectonic area of the piedmont overthrust belt, Permian-Triassic lithologic-stratigraphic reservoirs in the slope area, Permian-Triassic tectonic-lithologic reservoirs in the thrust belt at the western margin of the basin, and Carboniferous marine hydrocarbon reservoirs in Tainan sag, focusing on 17 favorable oil-gas exploration directions. Based on the different degree of understanding and research progress in hydrocarbon exploration, the exploration work is carried out at three levels, i.e., strategic deployment, strategic breakthrough, and strategic preparation, so as to find new breakthroughs in oil-gas prospecting.

Key words: exploration history, new type, new field, resource potential, exploration direction, Tuha Basin

摘要： 吐哈盆地早期围绕中—浅层正向构造带的常规油气藏进行勘探,在新层系、新领域和新类型油气勘探方面的研究比较薄弱。近年来,立足整体研究,基于重力-磁法-电法、地震、钻井及分析测试资料,开展了新一轮盆地级全层系构造精细解释、烃源岩评价、沉积与储层特征刻画、油气成藏富集规律研究,形成的主要认识如下:①吐哈盆地经历了海西期—印支期、燕山期和喜马拉雅期3期构造运动,发育基底断层、滑脱断层和山前逆冲断层3类断层,控制着不同时期、不同构造单元的展布及隆-坳格局;②盆地内发育石炭系海相—海陆过渡相、二叠系湖相、三叠系湖相和侏罗系湖相/煤系4套烃源岩,有效提升了油气资源潜力;③盆地内发育石炭系碳酸盐岩、二叠系—侏罗系碎屑岩和煤岩3类储层;④除常规油气外,盆地内还发育致密砂岩油气、深部煤层气等新的油气类型;⑤综合评价优选出侏罗系致密砂岩油气藏、深部煤层气藏、山前冲断掩伏带大构造区油气藏、斜坡区二叠系—三叠系岩性地层油气藏、盆地西缘冲断带二叠系—三叠系构造岩性油气藏、台南凹陷石炭系海相油气藏6个勘探新领域,聚焦17个有利油气勘探方向,根据认识程度、勘探研究进展的不同,按照战略展开、战略突破和战略准备3个层次勘探部署,以期实现油气勘探新突破。

关键词: 勘探历程, 新类型, 新领域, 资源潜力, 勘探方向, 吐哈盆地