|Abstract:By analyzing the characteristics of acidolytical hydrocarbon in sandstones of the paleo-channel uranium deposits in Upper Section of Saihan Formation, Lower Cretaceous in Central Erlian basin, the hydrocarbon composition, origin and source of the hydrocarbons in the acidolytical hydrocarbon can be discussed. Besides, combined with distribution and enrichment geological characteristics of uranium deposits in the area, the relationship between sandstone-type uranium mineralization and oil-gas in this area also can be preliminarily explored. The results show that, in sand body of Upper Section of Saihan Formation, content of CH4 and C2+ is positively proportional to uranium content, meanwhile, in the oxidation zone, the redox transition zone and the reduction zone, hydrocarbon content develops with obvious zonation. Gas composition characteristic parameters of acidolytical hydrocarbon, i.e. C1/ΣC, C1/C2+, C2/iC4, C2/C3, iC4/nC4, iC5/nC5, ln(C1/C2), and ln(C2/C3), show that hydrocarbon gas developed in sand body of Upper Section of Saihan Formation is organically formed oil-type gas, and mainly in the mature-high maturation stage, and mainly composed of crude oil associated gas and crude oil cracked gas. According to geochemical characteristics of source rock and analysis of hydrocarbon generation and expulsion history, it can be inferred that hydrocarbon gas in paleo-channel uranium deposit developed in upper section of Saihan formation of Lower Cretaceous is mainly generated from Aershan Formation of Lower Cretaceous(K1ba) lacustrine sapropel or partial sapropel source rock, followed by one section of Tenggeer formation (K1bt) low mature- mature lacustrine source rock. Main channels for upward escape of deep oil and gas consist of deep faults, unconformity surfaces, main sand bodies or fissures in study area, in which the deep faults and unconformity surfaces should be the key interest for of sandstone-type uranium deposits prospecting in this area. In the process of paleo-channel sandstone-type uranium mineralization in this area, oil and gas play a role in adsorption, reduction and ore-enrichment effect. The mineralization of sandstone-type uranium and oil and gas accumulation evolution are obviously controlled by the inversion developed in the end of late Cretaceous-Paleocene.