Applying New Automated Monitoring Workflow to Geothermal Wells: A Case of Muara Laboh field, Indonesia

Permanent well and reservoir monitoring with installation of pressure and temperature gauges is a standard technology in the geothermal energy production from subsurface reservoirs. A new automated monitoring workflow has been recently developed and tested for on-the-fly surveillance of injection wells during waterflooding of hydrocarbon reservoirs, employing time-lapse pressure transient analysis (PTA). The paper aims at applying the new workflow to geothermal energy production to monitor well and geothermal reservoir performances during cold water injection. Time-lapse PTA was developed and extensively tested for well surveillance in the oil and gas industry, now finding applications to monitor geothermal wells. The study started from mechanistic reservoir simulations of single-well cold-water injection into a hot formation to analyze capabilities of time-lapse PTA to evaluate thermal front and track its movement. Then, the new automated workflow is applied to geothermal wells from the Muara Laboh field, on-shore Indonesia, where changes of the well and reservoir performance indicators are used to monitor impact of the cold water injection. The results of the automated workflow were then compared to the simulation results. The simulation results confirmed the pressure transient behavior observed from the field data, where the reservoir cooling is reflected in the changes of the Bourdet pressure derivative. The comparison of the performance indicators with the reservoir simulation results has confirmed feasibility of monitoring of geothermal wells using the automated workflow. Capabilities of the monitoring workflow were therefore demonstrated with the analysis of the Muara Laboh field case with further verification with the simulation results. The new automated workflow may be used for retrospective analysis of geothermal well histories as well as for on-the-fly interpretation of new transient data enabling early detection of performance issues. This supports informed and timely decisions to optimize well and geothermal reservoir performances, paving the way to deployment of the new cost-efficient and scalable monitoring solutions in the geothermal industry.