A long term hydraulic stimulation study conducted at the Salak geothermal field
| Autor: | Riza Glorius Pasikki, Keita Yoshioka, Jim Stimac |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Metamorphic zone
geography geography.geographical_feature_category Microseism Renewable Energy Sustainability and the Environment 0211 other engineering and technologies Geology 02 engineering and technology 010502 geochemistry & geophysics Geotechnical Engineering and Engineering Geology 01 natural sciences Volcanic rock Permeability (earth sciences) Wellhead Caldera Sedimentary rock 021108 energy Petrology Geothermal gradient 0105 earth and related environmental sciences |
| Zdroj: | Geothermics. 82:168-181 |
| ISSN: | 0375-6505 |
| DOI: | 10.1016/j.geothermics.2019.06.005 |
| Popis: | Awi 18-1 is an injection well drilled in the Cianten Caldera, near the western margin of the Salak (Awibengkok) reservoir in west Java, Indonesia. As the initial well injectivity was low, a long-term hydraulic stimulation was conducted to improve the permeability and establish a better connection to existing natural fractures. A geologic model of the area was built by integration of surface mapping, log and core data, and well performance information. The well penetrated pre- and post-caldera volcanics, the caldera ring fault intrusion and contact metamorphic zone, and marine sedimentary rocks. Permeability was found primarily near the caldera margin in pre-caldera lavas and ring fault intrusion along steeply dipping N to NW and NE trending fractures that were partially sealed by mineral precipitation. A geomechanical simulation model was developed from the geologic model to understand the injectivity evolution mechanisms and behaviours under different injection conditions, and also predict long term future injectivity performance. The model domain contains the completed interval of a deviated injection well (Awi 18-1) and covers the majority of microseismic events observed during the course of the stimulation. It simulates injectivity evolution using fully coupled processes of heat and mass transfers in poro-elastic media. The model was history-matched against the injection data (i.e. pressure) by calibrating rock mechanical and fracture properties. A few what-if scenarios under different operation conditions were simulated to evaluate the effects of injection pressure and temperature on the injectivity. These what-if scenario simulations indicate that both colder injection temperature and higher wellhead pressure lead to better injection efficiency. Also, the higher pressure had prolonged impacts while the colder temperature impacts are limited at the early time. |
| Databáze: | OpenAIRE |
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