The Analyzation Of Middle-late Proterozonic Hydrocarbon Geologic Feature And Exploration Potential In Hang Jinqi Area

Hang Jinqi area is an important exporation area in Ordos Basin. In this area Proterozoic is a new exporation target. Referred to previous work, author traced horizon of T₉,T₁₂,T₁₃,T_g in Hang Jinqi area, and made up apparent-plumb depth maps and deposition thickness maps by using the LandMark workstation. Assuming the deposition thickness is dominated by palaeostructure elevation and subsidence framework, writer analyze Proterozoic palaeostructure feature. On the basis of relationship of palaeostructure evolution and the present structural feature togethered with hydrocarbon migration and accumulation and the source rock, writer pointed out several main oil and gas accumulation zones in Hang Jinqi area.According to the seismic cross section, the Proterozoic group is made up of the fault depression layer and the sag layer in Hang Jinqi area. The relationship of contact is angle disconformity. According to the imbedded dolomitic, the sag layer can be compaired with Jixian system, the fault depression layer can compaired with Changcheng system. The distribution of fault depression layer is restricted. The dominant sediments are greet stone, microconglomerate and partly clip gray clay stone. The sag layer widely distribute. It's border facies closely. The dominant sediments are variegated sandstone, microconglomerate and partly clip brown clay stone and carbonatite. Westward it turns into tital flat and open platform.The sandstone in Proterozoic group is developed universally. Lithologic character is lithic sandstone, quartz sandstone and feldspar-porphyry sandstone. The type of porosity mainly contains the remain intergranular porosity and the secondary dissolved pore, partly develop fissure. It belongs to the low porosity and low permeability reservoir and low porosity and particularly low permeability reservoir.Proterozoic palaeostructure evolution and the present structural feature indicates the relationship of the palaeostructure evolution and hydrocarbon migration, direction, accumulation and dissipate. Referring to previous work that the hydrocarbon source rock have hydrocarbon-expulsion, and the factor, meanwhile, thought of the conditions of translocating system and source reservoir cap assemblage, author forecasted three oil and gas accumulation zones, which are The west of Shie2 well-block, Shie2-Jin3 well-blocks and Jin13 well-blocks.