Assessment of geomechanical properties of Sakhalin shelf reservoirs based on modeling results

Abstract

Background. Due to the complex tectonic structure of the Sea of Okhotsk shelf and intense geodynamic activity in this area, specialized technologies are required to study reservoir properties. In this work, we implement the technology of secondary permeability estimation using the Kirinskoye and Ayashskoye license blocks as an example. The research objects included structural and lithologic traps of different complexes. It was found that the Prisakhalin shelf, including the Kirinsky and Ayashsky license areas, is subject to the modern shear stress field with the sublatitude-oriented axis of maximum compression. This initiates the formation of a local stress field, launches changes in the degree of fracture openness, and determines the secondary porosity and permeability of rocks. 3D modeling allowed us to calculate predicted permeability for each stratigraphic horizon. A significant difference of secondary permeability in the upper and lower stratigraphic horizons is noted.Aim. To evaluate secondary filtration and capacitance properties of reservoirs by geomechanical modeling.Materials and methods. Geomechanical modeling to assess the filtration and capacitance properties of Sakhalin shelf reservoirs was carried out using the ROXAR software package.Results. This work allowed not only the filtration efficiency to be predicted, but also the processes occurring in the geological section of the shelf of the Sea of Okhotsk to be elucidated.