关键词: 鄂尔多斯盆地, 河套盆地, 六盘山盆地, 银川盆地, 渭河盆地, 油气矿权, 油气矿权空白区, 矿权拓展

Abstract: Ordos Basin and its surrounding basins such as Hetao, Yinchuan, Liupanshan, and Weihe are characterized by coexistence of multiple types of resources in one basin, and they have prominent resource advantages in China’s large onshore basins. However, the degree of resource exploration is low, and there are a large number of mining rights blank zones, which are the major targets for favorable area screening and mining rights and resource space expansion of oil companies in the future. After analyzing new discoveries, summarizing new geological understanding, and correlating hydrocarbon accumulation conditions and resource potential in mining rights blank zones with the adjacent exploration areas, the study results indicate that: (1) The Upper Paleozoic coal seams and dark mudstone have a large thickness and high hydrocarbon generation intensity, and the structural settings are stable in Wanzhen area in the middle section of the eastern basin margin, showing exploration potential of tight gas and deep coalbed methane in the Upper Paleozoic. (2) The Carboniferous-Permian coal seams have a large residual thickness and moderate burial depth in Hangjinqi and Dongsheng areas in the northern basin margin, which are favorable areas for coalbed methane and coal chemical industry. (3) The continental shelf facies shale was developed in the Middle-Late Ordovician in the western basin margin, with a wide area and good hydrocarbon source conditions. Multiple platform marginal reef or fractured type oil and gas reservoirs mainly supplied by source rock in Ulalik Formation (Pingliang Formation) have been discovered. Based on the study of preservation conditions, it is believed that Shigouyi syncline and Taole fault terrace zone in the western basin margin are favorable areas for discovering the Lower Paleozoic carbonate and marine shale oil and gas reservoirs. (4) Among the surrounding basins, Linhe Depression in Hetao Basin is the most favorable exploration area. Two sets of high-quality source rocks were deposited in the Lower Cretaceous Guyang Formation and the Oligocene Linhe Formation in most areas in Linhe Depression, with strong hydrocarbon generation potential. Surrounding the main hydrocarbon generation Naoxi sub-sag, multiple sets of deep strike slip faults were developed in the southeast fault terrace zone, showing good connection to source rock. The high-efficiency hydrocarbon accumulation mode has been confirmed. (5) The Triassic and Jurassic source rocks were developed in Liupanshan Basin with good hydrocarbon generation conditions similar to those in Ordos Basin. The deep formations in the basin are worthy of further exploration. (6) The saline lake facies source rock in Qingshuiying Formation and oil-bearing structures were proved by wells in Yinchuan Basin. The structural belt in the peripheral mature hydrocarbon generating sag in the northern basin is a favorable orientation for exploration. (7) Weihe Basin and Huhe Depression in Hetao Basin are located in economically developed areas, and abundant shows of water soluble helium gas, geothermal energy, and biogenic gas have been penetrated by drilling activities. The oil and gas co associated resources in these areas are complementary to conventional oil and gas exploration, and the in-situ transformation and comprehensive utilization of resources can be achieved. After study, it is suggested that 10 new mining rights should be established and planned in favorable areas such as Wanzhen, Heyang, Hangjinqi-Zhungeerqi, Taole fault terrace zone, and Shigouyi syncline in Ordos Basin, Haiyuan-Guyuan Sag and the piedmont nappe structural belt in Liupanshan Basin, the southeast fault terrace zone in Linhe Depression and Huhe Depression in Hetao Basin, as well as Pingluo Sag in Yinchuan Basin. In addition, it is recommended that relevant companies should strengthen the pre evaluation and pre research in mining rights blank zones, and actively evaluate and demonstrate oil and gas potential in new blocks, so as to lay the foundation for maintaining the dynamic balance between farm-in and farm-out of mining rights and ensuring survival space of oil companies.