Relationship between Groundwater and Hydrocarbon Accumulation-Preservation in Sedimentary Basin
Hydrodynamic units in a petroliferous sedimentary basin can be categorized as follows: 1) compaction-driven centrifugal flow; 2) relief-driven centripetal flow; 3) cross-formational flow with/without evaporation; and 4) lagged flow. In general, the meteoric water infiltrates asymmetrically in the margin of basin and centripetal flow develops. The central depression is an area of centrifugal flow caused by mudstone-compacted water. Centrifugal flow and centripetal flow converge and result in cross-formational flow. The distributions of hydrochemistry field are controlled by the hydrodynamic evolution and the formation mechanism of groundwater in sedimentary basins. The groundwater concentrated in the cross-formational flow area results in relatively higher concentration. Centrifugal flow driven by sediment compaction is the main driving force of the oil-gas migration and accumulation in the sedimentary basins.