Genetic mechanism and reservoir control model of underwater paleo-uplift beach bar in Gasi area,Qaidam Basin
Beach bar is an important reservoir of oil and gas reservoirs,which plays an important role in controlling oil and gas accumula-tion.However,the research on formation mechanism of beach bar and its control on oil and gas reservoirs in the underwater paleo-uplift structure is relatively little,which needs to be further revealed.In this paper,through core analysis,microscopic observation,well seismic interpretation and other means,the paleo-sedimentary environment of the underwater paleo-uplift beach bar in the Gasi area of the Qaidam Basin was restored,the geological structure characteristics and sedimentary rock characteristics of the area were clarified,the formation mechanism of the beach bar was revealed,and the beach bar accumulation model was established.The results show that:①The sedimenta-ry system of the transition from shore-shallow lake facies to braided river delta is developed in the underwater paleo-uplift structure of the upper Ganchaigou Formation in the Gasi area.The stratigraphic lithology is mainly mudstone,siltstone and fine sandstone.②The paleogeo-morphology of the study area is high in the northwest and low in the southeast.The beach bar mainly accepts the Alar provenance deposi-tion from Shaxi-Hongliuquan,and develops a large area of beach sand body under the action of waves and coastal currents.③Gasi paleo-uplift developed before the Cenozoic era,and produced a large number of faults.The beach-bar sand bodies are widely distributed in the plane and the thickness of sand bodies is thin.In the vertical direction,it is a cyclic superposition distribution,which is a curved"strip",with a large number and relatively scattered.④The oil and gas reservoirs in Gasi area are structural-lithologic composite reservoirs con-trolled by paleo-uplift,faults and beach-bar sand bodies.
Qaidam Basinpaleo-upliftbeach bargenetic mechanismreservoir control model
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维普
