| Abstract |
Mature geothermal fields like The Geysers, the world's largest, are increasingly encountering superheated steam conditions within their formations. To address the decline in steam production, supplementary water sources have been integrated into injection programs, enhancing field performance since 1995. This study seeks to optimize injection management of The Geysers by modeling superheated steam to boost productivity and maintain pressure through strategic injection methods. Optimizing water injection strategies—considering the quantity, timing, and specific injection points—has a critical impact on the field’s longevity, steam output, and electricity generation capabilities. Effective strategies necessitate a balance between maintaining pressure, preventing thermal breakthrough, cooling the reservoir, and maximizing recharge potential. A comprehensive numerical model is crucial for evaluating these factors, as it accurately represents the underlying physical processes. The aim of this study is to leverage the superheat levels observed at the wellhead to refine the numerical model. Traditional models with low resolution often fail to accurately calculate steam generation from the de-superheating process due to their coarse grid size. This refined model, featuring over 780,000 grid blocks, significantly improves the precision of steam calculations from de-superheating. It also thoroughly examines the effects of steam quenching on production-injection synergy to avoid the collapse of the steam chest and prevent a decline in steam production. Overall, this model is a valuable asset for managing The Geysers and other geothermal fields facing superheat conditions. By optimizing injection strategies regarding rate and location, operators can effectively utilize the resource, ensuring continued field performance and maximizing power generation. |