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TRANSCRIPT
An overview of surface geothermal exploration in Papua New Guinea
Ms. Maxine LahanManager
Geophysical, Geochemical & Geothermal Mapping BranchGeological Survey Division, Mineral Resources Authority
PAPUA NEW GUINEA
STAR 2016:
The Pacific Islands Science, Technology
and Resources Conference
6-8 June 2016
Tanoa International Hotel
Nadi, Fiji
� Introduction� History of geothermal studies� Recent Government Initiatives� PNG Tectonic setting� MRA geothermal investigations� Potential prospects� Conclusion
Outline
Introduction
PNG
NZ
Indonesia
Philippines
Japan
SI/Fiji/Vanuatu
Seismicity of PNG region
Earthquakes of magnitude 6 or greater (1973-2012) Depths: Orange =0-35, yellow=35-70,
green=70-150, blue=150-300, pink=300-500, red=500-800km.
History of geothermal studies
� Geothermal studies conducted 60 years ago.
� 1954 – First geothermal study by Reynolds – Garua Harbor, Talasea
� 1960 – Studt, NZ Govt Scientist – Rabaul thermal field
Compared NZ fields and recommended Matupi-Rapindik area.
Geophysics survey, infrared imaging, and minerals studies continued later.
� 1966-69 – detailed studies on New Britain Island thermal fields by Heming and Smith under BMR Aust.
Mores studies on volcanoes, geology, chemistry, etc.
� 1974 - GoPNG request NZ Govt assistance for geothermal assessment.
GSNZ scientists Grindley & Nairn visited New Britain Island & MBP thermal sites. Recommended resistivity surveys and further geological studies.
� 1975 – BMR Aust. Delegated to GSPNG after independence.
Mineral district studies took prominence.
� 1988 – GoPNG requested UNDP for assessment 14 years after 1st assessment.
Stefansson reviewed all data held by GSPNG, recommended
3-year national exploration program, geothermal unit in GSPNG, staff training, overseas expert assistance.
� 1989-2008 – Recommendations not implemented.
56MW power plant installed on Lihir
Recent Government Initiatives
1. REVIVE GEOTHERMAL STUDIES
• 2009, GSD MRA, WB assistance plan to map explored and unexplored geothermal sites
• 2009, First geothermal mapping on Kairiru Island, ESP.
• 4 Provinces visited and mapped, hot springs sampled, analysed and results reported.
2. DEDICATED GEOTHERMAL UNIT & STAFF TRAINING
• 6-months geothermal training program in Iceland introduced in 2010
• 2011, staff training in NZ, funded by WB.
• First staff trained in Iceland 2012, funded by Iceland Govt.
Geothermal position established and dedicated unit take charge.
Total of 5 staff trained in Iceland, 1 to Japan this year.
• Plan to conduct subsurface studies
Geophysical equipment required; (TEM) acquired by MRA.
Seeking assistance to acquire MT equipment.
Recent Government Initiatives
3. POLICY & REGULATION
• Geothermal Resource Policy
Lack of policy directive from Govt despite numerous studies , assessment and
identification of huge potential.
NEC directive to DMPGM for creation of policy in 2009, 2 decades after 1988 UNDP
report.
DMPGM submitted final policy document to NEC in 2015
COP21 Climate Change Agreements - focus on geothermal , clean energy over fossil
fuels
• National Energy Policy (draft)
Formulated by DPE and DP&E, currently undergoing Govt vetting process.
Under this policy; National Energy Authority will be created.
Govt institutions responsible for the energy sector undergo
organisational changes to realise the objectives.
Achieve GoPNG’s energy targets outlined in Vision 2050 & PNGSDP2030
Tectonic Setting
� Australian Craton (Papuan Basin) which underlies the Fly Platform and much of New Guinea as a rigid continental block; Two distinct structural zones, stable platform and fold belt.
� New Guinea Orogen (Collision
Zone) which forms the mountainousspine of the country, resulting fromcollision between the Pacific andAustralian plates. Further divided intothe Western (Highlands and Ramu–Sepik regions) and Eastern (PapuanPeninsula and Islands) Orogens),representing a composite terrane ofmetamorphosed sediments that haveundergone fold thrust beltdeformation, island arc magmatismand oceanic crust obduction;
� Melanesian Arc (Volcanic Islands) is built almost entirely by volcanic activity. Four main rock units: Plio-Quaternary volcanics (and volcanoes); Plio-Quaternary volcanogenic sediments; Miocene limestone (gently dipping); Eocene-Oligocene basement volcanics (with intrusive rocks, e.g., diorite); rocks usually strongly jointed and faulted.
Three major geological terranes:
MRA surface geothermal mapping
Kairiru Island
7 manifestations mapped, 3
sampled
Temp. 30-75; pH 7.4-7.7
Morobe
24 manifestations mapped
13 springs sampled
Temp:40-70 °C; pH 7-9
West New Britain
50 manifestations mapped,
19 hot spring samples
Temp: 50-102°C;pH 1-7
Milne Bay
7 manifestations mapped
4 hot springs sampled
Temp. 78-103 °C; pH 1-7
Lihir – 56 MW
Hot spring sampling
Surface manifestations
Water chemistry results
District/
Province
Field Hot Spring Thermal water
classificationReservoir Temp. (Cation
Geothermometry)
Kairiru Is.
East Sepik
Victoria Bay Puruwan,
Waimkafur
Neutral chloride alkaline water 85 – 125 °C
Wau-Bulolo
Morobe
Wau
Bulolo
Myann,
Wandumi,
Buluwat
Peripheral waters (most hot
springs mixed with cold
surface/ground water)
Unreliable results
West New
Britain
Talasea Pangalu,
Talasea
Neutral chloride alkaline water 200-300 °C
West New
Britain
Talasea Wudi, Garu,
Haella, Matagele
Acid sulphate waters
West New
Britain
Hoskins Silanga ,
Kasiloli
Neutral chloride alkaline water 240 – 300 °C
Fergusson Is.
Milne Bay
Deidei Seuseulina,
Yaiyaiboalana,
Bolousunamo
Neutral chloride alkaline water 260 - 270 °C
Fergusson Is.
Milne Bay
Iamalele Munamelana Acid sulphate water
*Liquid analysis_V3_powell-cumming
Potential prospects
• Talasea-Pangalu field – 200-300 °C, chemistry complicated by seawater, on State land, potential users.
• Kasiloli-Silanga field – 240 – 300 °C, possible complication of chemistry by seawater, on wild life conservation land.
• Deidei field – 260 – 270 °C, on customary land.
Potential sites yet to investigate• Rabaul, East New Britain Province
• Karkar Island, Madang
Conclusions
• Detail geological mapping
• Subsurface investigations: geophysical
(MT/TEM Resistivity) surveys
• Map and sample new geothermal areas
• Policy & Regulatory frameworks
