Drilling Activity in the Mataloko Geothermal Field Ngada-NTT, Flores Indonesia

Abstract

Drilling activity of MT-2 was completed with setting 4î perforated casing to a depth of 180 m (TD = 180.02 m) on 3 February 2001. The first run of P-T logging tool to a depth of 104 m on 8 January 2001 showed down-hole temperature of 75.8?C. The second run recorded temperature of 78.1?C, then became 112?C and 130.4?C during the tool stayed for 2 hours and another 1? hours at the bottom. A flow test with Lip Pressure Method was successfully done to MT-2 on 22-27 January 2001. Steam flow rates on 3î flow line varied between 10.87 ñ 10.98 ton/hour at WHP of 7.9 Kscg. At WHP of 5.9 ñ 6.0 Kscg, steam flow rate ranged from 14.48 ñ 14.71 ton/hour and a flow line temperature of 135 ñ 140?C. Using 4î flow line, steam flow rate was about 14.29 ñ 16.34 ton/hour at WHP of 3.1 ñ 3.9 Kscg with a range temperature of 128 ñ 133?C. A maximum WHP of 14.0 Kscg was recorded while MT-2 shut-in on 17 - 18 January 2001. Chemical analyisis (WESTJEC) during the flow test showed a very low of gas content in the saturated steam (NCG = 0.261 ñ 0.291 vol% or 0.612 ñ 0.692 Wt%, CO2 in NCG = 90.81 ñ 90.99 vol%, H2S in NCG = 6.33 ñ 6.59 vol% and residual gas in NCG = 2.61 ñ 2.68 vol%). Subsurface lithology of MT-1 consists of tuff breccia, pyroxene andesite, hornblende andesite with minor layers of tuff. All rocks have been altered into argillic type. Alteration intensity (SM/TM) varies between 30 ñ 90% and contain about 2 ñ 60% swelling clay. The lithology of MT-2 is nearly the same as the MT-1 well.