Basin Analysis and Hydrocarbon Potentials of The Bristol Bay Basin, Alaska Peninsula

In this study, basin analysis and hydrocarbon potentials of the Bristol Bay Basin, Alaska Peninsula, was evaluated to identify potential leads/prospects, estimate recoverable reserves and recommend possible key areas for further exploration activities. The method adopted involved detailed well-log interpretation, integrated petroleum system analysis, determination of petrophysical properties, seismic facies analysis, fault & horizon mapping, time-to-depth conversion, risk analysis of identified prospect(s) and reserve calculation. The basin is characterised by strike-slip faulting, extensional faulting and transpressional folding. Two horizons were mapped. Two plays were identified: Tertiary and Mesozoic age plays. Two genetic sequences were identified with their associated system tracts. Seismic facie was interpreted based on reflection amplitudes, reflection geometry and continuity. The continuous high and low amplitude facie (D) and the high and low amplitude convergent facie (Cbhl) correspond to the sands of LST and have the highest reservoir percentages. The petrophysical analysis gave porosity values ranging from 19% to 27% and Net/Gross values ranging from 0.70 to 0.90 for the Tertiary Tolstoi Formation, having 74.73 MCF of gas and 43% geologic chance of success. Risk analysis shows that the Tertiary Tolstoi prospect may be compromised by the presence of gas chimneys and the sealing integrity of the trap, which is a 3-way closure. Based on the limitations encountered in this study, acquiring 3-D seismic data with a dominant frequency of 30 Hz to 40 Hz, checkshot data and adequate fault-seal analysis could enhance the success rate of hydrocarbon exploration in the Bristol Bay Basin.