An integrated geomechanical model for a heterogeneous carbonate reservoir in SW Iran, using geomechanical unit concept

摘要

Detailed subsurface modeling, help safe and cost-effective operations. The proposed model by integration of geological data, petrophysical data, and geomechanical model allowed for better reservoir characterization, development, and management. Well data such as leak-off test or mini-frac and image logs are found essential for constructing the geomechanical model. Since these data are rarely available, the geomechanical unit (GMU) concept is used in this study to cover such a gap. Based on facies index (percentage of grains, cement, dolomite, matrix, or microporosity), uniaxial compressive strength (UCS), and porosity, the studied formation was divided into five GMUs. From GMU1 to GMU5, the amount of cement and dolomite, UCS, cohesion, friction angle, fracture toughness, and brittleness increase, whereas porosity, bioclasts/grains, and clay content decrease. Optimization of geomechanical model by GMU concept was caused to show a good correlation between GMUs distribution and breakouts and breakdowns of the studied well. The GMU1 and GMU2 were found more susceptible to breakout, the GMU4 and GMU5 more susceptible to breakdown, while the GMU3 contains both breakdown and breakout zones. For a safe drilling in the studied formation, the highest breakout pressure (11.5 ppg) was observed for the GMU1 and GMU2 and the lowest (8 ppg) was seen for GMU4 and GMU5. The results of this study may help in designing, based on optimized geomechanical units, and safe mud weight window for drilling in heterogeneous reservoirs.