Fault seal analysis for VS area, block 16 -1/15, Cuu Long Basin, Viet Nam

Abstract

Fault-bound traps represent an important class of hydrocarbon-bearing structure. Whether a fault can seal hydrocarbons on a geological timescale may be controlled by one or more of three conditions: (1) sealing due to lithological juxtaposition, where reservoir rock is juxtaposed against sealing rock across the fault; (2) sealing by the fault damage zone, which forms a barrier composed of low-permeability clay within the fault zone and (3) the tectonic activity of the fault, as during faulting, hydrocarbon accumulations can be destroyed and leakage along the fault zone. This research employs an indirect method to establish a correlation between pressure and the sealing properties on fault surfaces, such as the SGR (Shale Gouge Ratio), across various formations under the same geological conditions from all fields within the region and around the world. This aids in assessing the sealing potential of the faults. Evaluate the fault seal capacity according to 3D model for the structures in Oligocene D, Oligocene C and Lower Miocene sediments to serve the assessment hydrocarbon potential in VS area and reduce the risk for further exploration - appraisal work in block 16-1/15, Cuu Long basin. Geology, seismic and petrophysical data were used to construct 3D structural frameworks, lithology model and Vclay model. Parameters such as fault throw, Vshale, lithology, bed thickness, burial depth history, fluid density and pressures, ect. are incorporated into fault seal analysis and also estimate the maximum hydrocarbon column height can be held by each fault in study area, therefore helping to assess the hydrocarbon potential in undrilled structures in VS area.