Publications

Integrated geomechanical models that describe the rock strength, fluid pressures, and in-situ stresses for the Senoro and Tiaka Fields in South Central Sulawesi have been developed using drilling data, geophysical log data (including resistivity image data), seismic data, and production/well testing data. Rock strength at Senoro Field has been estimated by using published relationships between rock strength and log data that have been calibrated using laboratory testing results. At Tiaka Field, laboratory testing data were not available, but comparison of the Senoro and Tiaka Fields suggests that rock strength at Tiaka is slightly higher. Modelling of the stresses, coupled with the wellbore orientations and rock strengths, indicates that Senoro and Tiaka Fields are characterized by a “normal faulting” state of stress, where the maximum compressive principal stress is vertical (Sv=S1), and the intermediate and least compressive principal stresses (SHmax=S2 and Shmin=S3) are horizontal. However, the difference between the stresses is relatively small, and there is not a strong directional trend. Because no breakout- or drillinginduced tensile fracture were conclusively observed in borehole image data, it was not possible to constrain the orientation of SHmax based on data from either field. Based on first-motion-solution analysis of two nearby earthquake events, the azimuth of SHmax is inferred to be ~E-W. * Baker Hughes – GMI Geomechanics Services ** JOB Pertamina Medco Tiaka Senoro Proposed development at both fields will involve production from fractured carbonates. Analysis of fracture orientations and of the location and orientations of faults has been considered, in the hope of enhancing production. At Tiaka, the proposed development involves drilling extendedreach wells to the north and south. The risk of difficult-to-predict losses exists in the depleted Tomori formation. Additional risk from shear reactivation of faults or fractures leading to casing shear or catastrophic circulation loss is also present.