Abstract

Faults commonly trap and impact the flow of fluids such as hydrocarbons (HC) and therefore are of economic significance. During HC-exploration, analysis of the sealing capacity of faults can impact both the assessment of the probability of finding hydrocarbons and also the estimate of the likely resource range. The present study primarily aims to ascertain the role of faults in entrapment of HC based on fault seal analysis (FSA) in a mature brown field of Upper Assam Shelf North (UAN) of AssamArakan Basin. Faults are identified and its architecture, throw, heave and orientation are analyzed based on 3D seismic data. Primarily, two sets of faults viz. NE-SW trending longitudinal faults have been offset by NW-SE or N-S transverse faults in the study area. 3D Geo-cellular model has been prepared, incorporating drilled well data, geological information, petro-physical & seismic interpretation data to capture the vertical as well as lateral heterogeneities and to analyze structural disposition across faults and fault sealing properties. Sealing nature of faults has been analyzed using properties such as Facies Juxtaposition (FJ) and Shale Gouge Ratio (SGR). The study brought out the sealing potentiality of entrapment faults at different pay levels, which helped in de-risking the prospects of the study area.