Well Permeability Enhancement through Hydraulic Stimulation Conducted in the Mt. Apo Geothermal Project, Philippines

Abstract

The Mt. Apo Geothermal Project (MAGP) is located within the 701 hectares geothermal reservation in the northwest flank of Mt. Apo. Steam production levels have been successfully maintained at or above the contracted electricity generation since 1997 until 2008 when injected fluid returns have already affected steam production resulting to further steam decline. Steam production would be improved by moving brine injection from current infield locations to outfield locations. During the recent outfield drilling campaign, wells drilled were of low permeability which limited their injection capacity. Hydraulic stimulation has been applied to enhance permeability of completed wells which involves pumping of water into the well at high pressure. Hydraulic stimulation was implemented in well K6 for about 1-1/2 months. Seismic events in the area increased during the activity. However, based on wellhead pressure and flowrate monitoring and an injectivity test, no indication of permeability enhancement was achieved. Modification of the injection program is recommended. Alternate well warm-up and injection can be conducted in well K6.