Structural Features North Qaidam Basin And Closed Research

Through the studying of geologic background,stratigraphical features and depositional characteristics in North Qaidam region,we can judge the situation of the cap rock and fault in the region.Thus oil gas sealing comprehensive evaluation of the region can be seen. According to the studying of lithology,purity, thickness,consistency and the reservoir-cap rock relations of combination,regional seal and direct seal can be confirmed.Regional seal is one of the important conditions determines for preservation conditions.As long as have good regional seal,even if there is worse direct seal,oil and gas will be redistributed under the regional seal.For these reasons,oil and gas will not be loss a lot.Microscopic sealing mechanism of cap rock mainly includes physical property sealing,pressure sealing and hydrocarbon concentration sealing.In North Qaidam region, physical property sealing is the most important closed form of mudstone cap rock.Over pressure seal is the second important closed form.As we are not sure if it exists effective source rock in tertiary of North Qaidam region,so there is no hydrocarbon concentration sealing.Physical property sealing(capillary sealing effect) is the most important mode of the sealing ability of cap rock.Geornetric features of fault development in North Qaidam region made its influencing factor in sealing are different from any other extensional regions. Finally, detailed description of formation is given afer seismic interpretation has been taken in North Qaidam region.All of these have very important significance to the description of cap rock and fault in North Qaidam region.These are also provided a theoretical basis for analysis of capping situation of oil and gas reservoir.