Isotopic evidence for magmatic and meteoric water recharge and the processes affecting reservoir fluids in the Palinpinon geothermal system, Philippines

Journal Article · Fri Oct 01 04:00:00 EDT 1993 · Geothermics

DOI:https://doi.org/10.1016/0375-6505(93)90034-K· OSTI ID:143823

Gerardo, J Y; Seastres, Jr, J S ^[1]; Nuti, S; D`Amore, F ^[2]; Gonfiantini, R ^[3]

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1. Philippine National Oil Co.-Energy Development Corp., Fort Bonifacio (Philippines). Geothermal Div.
2. Ist. Internazionale per le Ricerche Geotermiche, Pisa (Italy)
3. International Atomic Energy Agency, Vienna (American Samoa). Isotope Hydrology

Stable isotopic compositions of meteoric and geothermal waters indicate that the Palinpinon geothermal system of Southern Negros is fed by a parent water that originated from a mixture of local meteoric (80%) and magmatic (20%) waters. The meteoric water has an isotopic concentration of {minus}8.5{per_thousand} and {minus}54{per_thousand} in {sup 18}O and {sup 2}H, respectively, which corresponds to an average infiltration altitude of about 1,000 m above sea level. With exploitation of the system and injection of wastewaters to the reservoir, the stable isotopic composition became heavier due to significant mixing of geothermal fluids with injection waters. Incursion of cooler meteoric waters, which is confirmed by the presence of tritium, also leads to the formation of acid-sulfate waters. Stable isotopes are effective as ``natural tracers`` to determine the origin and mixing of different fluids in the reservoir.

• OSTI ID: 143823
• Journal Information: Geothermics, Journal Name: Geothermics Journal Issue: 5-6 Vol. 22; ISSN GTMCAT; ISSN 0375-6505
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
CHEMICAL COMPOSITION
GEOCHEMISTRY
GEOTHERMAL FLUIDS
HYDROLOGY
ISOTOPE RATIO
MAGMATIC WATER
METEORIC WATER
PALIMPINON GEOTHERMAL FIELD
WATER CHEMISTRY