Advanced Formation Testing Using a Wireline-Deployed Formation Testing Tool to Characterize In-Situ Stress Parameters in a Depleted Niagaran Pinnacle Reef Carbonate Reservoir

Proper planning and design of a CO₂ storage project in a depleted oil field requires that key geomechanical parameters of the reservoir and caprock formations are characterized, namely minimum horizontal stress (Shmin) magnitude and orientation. In this study, a wireline formation testing tool (WFT) configured with a straddle packer with a 1-meter long spacing, was used to conduct multiple hydraulic fracture injection (micro-frac) tests to determine Shmin magnitude during a single deployment of the tool. Acoustic image log was used to determine the orientation of Shmin and maximum horizontal stress (SHmax). The results of the micro-frac tests at different depths in the reservoir and overlying caprock, and implications for using the depleted reservoirs for future CO₂ storage are discussed. Also, an analysis of how minimum horizontal stress (and corresponding fracture pressure) increases during the process of filling the reservoir with CO₂ was performed to estimate actual fracture pressure during the reservoir filling process. We refer to this as “dynamic” fracture pressure.