| Title | Soil Stabilization Using Horizontal Deep Drainage at Awi-14 Brine Line Pipe and Well Pad, Star Energy Geothermal Salak Field, West Java, Indonesia |
|---|---|
| Authors | Adi Gunawan TP, Satrio Wicaksono |
| Year | 2017 |
| Conference | Indonesian Geothermal Association Conference |
| Keywords | Salak, Awi-14, geothermal, geohazard, landslide 2010, geotechnical analysis, geological engineering, construction |
| Abstract | Salak geothermal field has several locally steep slopes that could yield the possibility for large-scale landslides. During heavy rains on 2003, Salak recorded significant landslides that caused major damage and shut down a part of Salak operations for 3 months. Over the period 2010- 2012 several new landslides have been identified around the Awi-14 injection location. The landslides have significantly impacted surface facilities including pipeline, road, and well pad, and will have a potential to impact injection strategy within Salak field. Steep slopes, high rainfall, high porosity, and loosely consolidated near-surface rocks were the main contributing factors to the landslides in the area that will threatening the Awi-14 brine line pipe. During heavy rain, the soil has the tendency to become over-saturated, triggering slope failure that can lead to landslide depending on the nature of the underlying soil. On 2011, several geotechnical analyses have been applied including shallow drilling for soil investigations, geoelectrical, geological engineering mapping, and geophysics survey. Those applications have helped to identified landslide mechanisms around the pad, quantify the risks at identified critical areas, and provided recommendations for cost effective mitigation measures. High groundwater level at Awi-14 brine line pipe has identified as the main problem, it has decreased the soil strength so one of the solution is to lowering the groundwater level. Design and installation of Horizontal Deep Drainage (HDD) systems were done for lowering the ground water level. This method would prevent occurrence of further landslides and restore the stability and viability of Awi-14 as an injection well in the Salak field. |