| Title | Evaluation of the Hydrothermal System of Biliran Island, Philippines |
|---|---|
| Authors | Nilo A. Apuada, Gudmundur F. Sigurjonsson, Alejandro F. Oanes |
| Year | 2010 |
| Conference | World Geothermal Congress |
| Keywords | Biliran Geothermal Field, hydrothermal system, geothermal resource |
| Abstract | The Biliran Geothermal Field located on the northern tip of Leyte was the subject of geothermal investigation from 1979 to 1982 by the Philippines geothermal company PNOC-EDC and the KRTA of New Zealand. Results of the geoscientific studies lead to drilling three exploratory wells: BN-1, BN -2 and BN -3. Wells BN-1 and BN-2 encountered neutral Cl fluids with TSi02 temperatures of 250oC and 210oC respectively. Both wells have a Cl/B ratio of 10, showing the homogeneity of the source fluid. BN-1 was successfully discharged but on the 6th day of discharged the well spontaneously died due to pressure drawdown. BN-2 was able to discharge for three weeks and then died naturally due to mineral deposition on the wellbore. BN-3, which was drilled closer to the Vulcan Fault, discharged acid Cl-SO4 waters having a weirbox pH of 3.0. The well reached a Clres of 2,000 mg/kg in its 15 days discharge. It has the very high SO4, Mg and Fe concentrations typical of acid fluids. The discharge, which was accompanied by high excess enthalpy (360-1403 kj/kg), delivered enough steam to generate from 5-6 MWe. However, the corrosive nature of the discharge fluid destroyed the well head and forced the PNOC-EDC to shut down the well. Recent geoscientific study revealed the existence of exploitable geothermal source located at Libtong-Vulcan-Kalambis. |