Analysis on the Hydrocarbon Accumulation Conditions and Exploration Potential of Deep Middle-Lower Jurassic Reservoirs in South Turgay Basin

Abstract

According to comprehensive researches on the structure, source rock, accumulating conditions and exploration potential, the accumulating conditions are relatively good in the Middle-Lower Jurassic formations where the source rock has reached the maturity threshold at 2200 m, and as the primary source rocks, J1 and J2ds are thick and widely distributed, but the J2kr source rock reached the maturity threshold locally in the center of the sag in the South Turgay Basin. Various fans at the sag slope can serve as good reservoirs, which is favorable to develop lithologic traps. In addition, in the Middle-Lower Jurassic corresponding to the basin rifting, complicated fault systems were developed with a lot of faulted blocks and faulted noses which are favorable for hydrocarbon accumulation. For the deep J12, on the basis of geologic analysis and in combination with the hydrocarbon migration and accumulation system, the paper points out three prospective slope zones, and each of which is further divided into three structural belts: high fault step, central fault step and low fault step, and the central fault step contains the best lithologic and lithologic – structural hydrocarbon accumulation belts.