Integration of 1-D Geomechanical Model for Minimum Horizontal Stress Estimation and Validation with Micro-frac Tests – Case Study from Touggourt Field, Algeria

Abstract

Abstract This study presents comprehensive geomechanical modeling of the tight Triassic reservoirs from the Touggourt field, eastern Algeria. The primary objective was to constrain minimum horizontal stress in the T1 and T2 reservoirs by microfrac testing. Wireline logs, direct pore pressure measurements, acoustic and resistivity image logs were integrated for geomechanical modeling. A strike-slip tectonic stress regime with NW-SE SHmax orientation was inferred. A pre-job geomechanical model was prepared for selecting optimum intervals for microfrac testing. Contrast in horizontal stress magnitudes, density-porosity, and rock-mechanical properties, expected breakdown pressure being within tool limit, and in-gauge caliper response have been considered for choosing the microfrac test intervals, while honoring the operator’s geological objectives. Based on the microfrac test data, we inferred a 0.88-0.94 psi/ft Shmin gradient with 1.04-1.08 psi/ft breakdown pressure gradient within these Triassic reservoirs. Integrated geomechanical approach in the pre-planning as well as real-time advisory facilitated successful formation break down in a very tight and strong lithofacies. High quality data acquired during microfrac operation yielded confident fracture closure interpretation and post-job geomechanical model calibration, which has critical implications in future drilling and completion optimization.