Fault seal capacity evaluation in block 04-3 of Nam Con Son basin, offshore Vietnam

The purpose of the study is to evaluate the fault seal capacity and hydrocarbon (HC) retention potential of the Miocene -Oligocene fault-bounded structures in Block 04-3, Nam Con Son basin, offshore southern Viet Nam. Seismic and well petrophysical interpretation data are used to build 3D fault model and stratigraphic model within the 6 selected structures. Parameters such as fault throw, bed thickness, Vshale, lithology, burial depth, and fluid density are incorporated into fault seal evaluation. The critical leak points at the Middle Miocene, Lower Miocene and Oligocene intervals on faults bounding the 6 structures are defined. Hydrocarbon column heights supported by the faults can be estimated using the empirical relationship between Shale Gouge Ratio and threshold pressure. The study predicts that the maximum gas column ranges from 136m to 252m in Middle-Lower Miocene reservoirs in the drilled structures and from 119m to 295m in Middle-Lower Miocene and Oligocene reservoirs in the undrilled structures.