Abstract
Two geothermal exploratory wells have been drilled in the Mataloko geothermal area in the central part of Flores, where geothermal energy is expected to be stored in large quantities. The first well MT-1 was planned to a depth of 1000 m at a site located in the northern side of Wae Luja River. While drilling at a depth of 207.26 m, a high pressure steam zone was encountered, causing steam to flow through the conductor casing. The valve was closed to prevent the steam to flow to the surface, but the steam started to appear at the surface. It was considered that a surface blow-out around the well might have occurred. Under these conditions, consolidation grouting around well MT-1 was carried. After the completion of the grouting operation, well MT-1 was successfully killed with fresh water followed by a cement slurry. Drilling of second well MT-2 was planned to a depth of 230 m at the same drilling site as well MT-1. A steam zone was encountered around 162.35 m during drilling. A temporary flow test was carried out successfully and the total depth was decided. A proper well test was carried out using the Lip-Pressure method (James, R., 1962). The testing included the recording of wellhead pressure, a parameter to calculate the steam flow rate. While fluids were being discharged, samples were taken for chemical and isotopic analyses. Based on the discharge test result, the maximum steam rate of 4.57 kg/sec. (16.5 ton/hr) was calculated.
