New Logging Tool for Enhanced Oil Recovery and Gas Storage Monitoring Applications

There is currently no production logging tool that can analyze in-situ gas composition in wells that intersect more than one pay zone. In high-value gas wells, zonal isolation is useful for enhanced oil recovery (EOR) applications such as injection monitoring, pressure maintenance, and identification of layers that contain low-calorific-value gas. To unlock these key applications related to gas reservoir management, a new production logging tool was developed that introduces downhole gas composition analysis to the production logging tool string. The tool does not require a formation seal and so can log continuously or at a station. For gas field applications with pressures above 3,000 psi, the estimated mole fraction errors in continuous logging mode are ~2% for methane and ~1% for ethane, propane, nitrogen, and carbon dioxide. In formations with lower pressures, station logs can achieve mole fraction errors < 1% for all components.