Characteristics of Fault Cementation Zone and Its Origin in Linpan Oil Pool of the Huimin Depression

Fault block oil reservoirs are well developed in Linpan oil pool of the Huimin depression. But the sealing mechanism of fault is not clear. The fault cementation zone characteristics and its origin are discussed by means of core data, well logging data, physical property and scanning electronic microscope analysis. The subsurface water rich in Ca²⁺ and Mg²⁺ migrates from deep formation to shallow part along the fault zone during faulting activity in Linpan oil pool. Calcite and dolomite deposit along the fault zone due to the decreasing geothermal pressure upward. As a result, the permeability of the fault zone decreases about one order of magnitude and the accumulated oil is well sealed by fault cementation zone.