Accumulation System of Cohabitating Multi-Energy Minerals and Their Comprehensive Exploration In Sedimentary Basin ———A Case Study of Ordos Basin,NW China

Multi-energy minerals,mainly refers to energy deposits such as petroleum,natural gas,coal and sandstone-type uranium ore hosted in sedimentary basins.It is concluded that not only do the various energy deposits cohabitate in the same basin,but also have some regularity with temporal and spatial distribution.The minerals formed in the same basin are an organic part of natural minerogenic(reservoir forming)system,which were accumulated during the whole evolution and reconstruction of basin.Primary mineralization process can be summarized as two:one is geochemical process,oxidized inorganic fluid including uranium and reducing hydrocarbon fluid formed redox barrier and uranium deposited in interface of the oxidation-reduction by chemical reaction;Second,the physical migration processes of organic fluid,which migrate to the high part of the basin and accumulated,formed oil and gas reservoirs or coal bed methane reservoirs.The formation process,which organic and inorganic mineral interrelating each other in the cohabitation system distributing in the space according to certain rules,occurred with the basin evolution.There are some links among these mineral deposits,which the characteristics of one kind of mineral deposits can imply other energy mineral information.It will be possible for the exploration of them in one basin to reach unified planning,information sharing and cooperative exploration.Ordos basin, as an example,the second largest sedimentary basin located in the central part of China,undergoing the structural evolution from rift to depression,became the westward decline structure in later Cretaceous where a large amount of various energy resources have been found.Studies have shown that Late Jurassic-Early Cretaceous tectonic evolution and the reformation from then on had a significant impact for the formation and location of multi-energy minerals in the Basin.Integrated the key elements of the various energy deposits forming,the evolution of Multi-energy minerals forming can be divided into three phase: the preparation phase of mineralization,the main mineralization and the preservation.The main mineralization phase can be subdivided into three stages:uranium aggregation,gas accumulation and oil accumulation.The accumulation system evolutions of multi-energy minerals in the basin are characterized by their obvious phasic development,and the commercial energy resources have been accumulated in a sequence of coal→uranium→gas→oil.Yishan slope area is favorable for exploration of oil,gas,coal and unconventional gas;Tianhuan depression and the thrust belts on the western edge of the basin are favorable for joint exploration of oil,gas,coal and uranium;Yimeng uplift and Weibei and Jinxi flexural fold belts are favorable for joint exploration of coal,coalbed methane and uranium.