Assessing Evolution of Natural Fracture Systems through Geomechanical Forward Modeling in the Northeast Betara Field, Indonesia

ABSTRACT: Hydrocarbon production from fractured reservoirs requires accurate mapping of the fracture network and their conductivities. Fracture networks develop during evolution of sediments mostly by tectonic and gravitational forces. Evolution of fractures was estimated by the geomechanical forward modelling technique in the northeast Betara Field, Indonesia. The present-day structure was regenerated through geological times. It simultaneously provides an estimate of rock deformations and other geomechanical variables such as stress magnitudes, stress orientation, and onset of rock failure. These attributes describe the distribution of the fracture network within the field. Restored seismic horizons at different geological times were used to perform geomechanical forward modeling. An explicit geomechanical simulation was performed at each geological timestep of the forward modelling process from the initial depositional configuration through to present-day geological structure. Fracture density and planes, which are defined by orientation and inclination of fracture planes, were derived from the computed stresses and irreversible rock deformations. The obtained present-day natural fracture network was validated against observed fractures from image analysis data in offset wells. Hydrocarbon production potential from the obtained fracture network was evaluated based on the state of stress on the individual fracture planes. “Sweet-spot” targets were identified based on high fracture intensity and critically stressed regions.