Conceptual Model of Mt. Natib Geothermal Area as Revealed by Electromagnetic and Drilling Data
Nilo A. APUADA, Wen J. WHAN, Fernando S. PENARROYO, Sherwin MENDIOLA and Ariel D. FRONDA
[Premier Geo-Exel, Inc., Philippines]
Interest in the geothermal development of the Mt. Natib geothermal area in Bataan Peninsula in the Island of Luzon begun in 1987 by the then PNOC-EDC (now EDC). Based on the results of the surface geoscientific investigation in an area of about 850 km², two (2) exploratory wells were drilled within the Natib Collapse Caldera. Well Na-1D was drilled to a depth of 2751.5 mVD (2859.0 mMD) with highest measured temperature of 282oC at the bottom of the well. Due to low permeability of the structures encountered, the well did not discharge. Well Na-2D reached to a total depth of 2916.12 mVD (3353.7 mMD) with a maximum measured temperature of 270oC at 2916.28 mVD (10 days shut). Three discharge attempts were made in this well and proved to be unsuccessful. Post-drilling geoscientific evaluation indicated the presence of exploitable hydrothermal system in Mt. Natib geothermal area. Hence, additional electromagnetic surveys such as CSMT and MT measurements were conducted in 2011 and 2018, respectively. Both CSMT and MT surveys results revealed the presence geothermal resource further E-SE of Na-1D towards the Mt. Natib and Natib Crater structure. The updated geothermal resource estimate based on MT, CSMT and drilling data, range from 33 MWe (P90) to 77 MWe (P50).
|        Topic: Exploration||Paper Number: 11006|