Relationship Between Cenozoic Superimposed Folds and Hydrocarbon Migration in the Gahainanshan Area,Eastern Qaidam Basin,China
The Carboniferous system in the Qaidam Basin is primarily distributed in the basin's eastern region.Significant findings have been made in the exploration of Carboniferous hydrocarbons,ushering in a new era for Paleozoic hydrocarbon exploration in the Qaidam Basin.The Carboniferous source rocks in the Qaidam Basin exceeded the threshold for hydrocarbon generation during the Early Permian,with oil generation being the primary outcome.The Paleocene-Pliocene period was the primary hydrocarbon generation phase for the Carbon-iferous system,with a predominant focus on gas production.The Qingdecan First Well,deployed in the Gahainanshan area of the Delingha Depression in the eastern Qaidam area,encountered hydrocarbon displays in two layers:the Carboniferous Keluke Formation and the Paleogene Upper Ganchaigou Formation.Based on the statistical analysis of structural elements,mapping of superimposed structures,comprehensive seismic interpre-tation,and analysis of hydrocarbon reservoir conditions in the basin,we determined that the superimposed folds,formed by early northwest(northwest-west)trending folds and later northeast(northeast-east)trending folds,developed in the Gahainanshan area during the Late Cenozoic.The northwest(northwest-west)trending folds and fault structures have created favorable traps for the Carboniferous source rocks.The northeast(north-east-east)trending structural compression reactivated pre-existing faults,causing Carboniferous oil and gas to migrate upward along the fault,forming secondary hydrocarbon reservoirs in the Shangganchaigou Formation.Ultimately,we established the signature of the coexistence of two oil and gas combinations in the Gahainanshan area.This study has reference significance for the exploration of Carboniferous hydrocarbon in the Qaidam Basin.
万方数据
维普
