Application of volumetric seismic attributes for complex fault network characterization on the North Slope, Alaska

Abstract

The deeper formations on the North Slope, Alaska presents a structurally complex geologic system. The complex system contains a number of reservoirs with large volume of hydrocarbons, many of which are fault-controlled. An ensemble of volumetric seismic attributes are computed on a large 3D seismic reflection survey to interpret different sedimentary horizons and investigate the structural complexity in a few key intervals, such as the Kekiktuk, Shublik, and Kuparuk formations. Second-order (curvature) and third-order (aberrancy) derivatives at long and short wavelengths are extracted on each of the intervals to better understand the faulting styles, geometries, and infer the multi-phase deformation history. The results from the most-positive and most-negative curvature attributes show that there are at least two types of faults in the study area, which includes WNW-trending faults and N-S and E-W oriented extensional faults. It is inferred that the WNW-oriented faults are controlled by the pre-existing basement structures, the influence of which decreases in the upsection. The extensional faults display single-tip and double-tip abutting relations with the pre-existing WNW-trending faults. The deepest Kekiktuk horizon shows the presence of mostly WNW-oriented faults, whereas the shallower Shublik and Kuparuk formations are pervasively faulted, containing both WNW and N/NNE oriented faults.