Hydrologic and geomechanical characterization of deep sedimentary rocks and basement for safe carbon sequestration in the Cook Inlet Basin, Alaska

Abstract

Understanding the hydrologic and geomechanical properties of sedimentary rocks and the underlying basement is important for the success of fluid extraction and injection operations, including carbon sequestration. This study analyzes the hydrologic and geomechanical properties of the reservoir (Hemlock Formation), overlying confining unit (Tyonek Formation), and underlying confining unit/basement (Talkeetna volcanics and Mesozoic igneous intrusive - diorite). This study shows the potential of fault slip due to carbon sequestration in the Cook Inlet basin of Alaska. We integrate core, well-log, and 3D seismic data to perform hydrologic and geomechanical analysis of the deep sedimentary formations, basement, and simulation of the fault slip potential (FSP). The FSP results show that faults have the potential to slip, depending on several factors, such as the local in-situ stress conditions, pore pressure, and CO2 injection rate. The azimuth of the maximum horizontal stress (σH) with respect to fault orientation is a critical factor for fault stability in the Cook Inlet basin.