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DETERMINATION OF THE TEMPERATURE HISTORY FOR THE U THONG OILFIELD AREA (SUPHAN BURI BASIN, CENTRAL THAILAND) USING A REALISTIC SURFACE TEMPERATURE
Author(s) -
Petersen H.I.,
Mathiesen A.
Publication year - 2007
Publication title -
journal of petroleum geology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.725
H-Index - 42
eISSN - 1747-5457
pISSN - 0141-6421
DOI - 10.1111/j.1747-5457.2007.00289.x
Subject(s) - geothermal gradient , vitrinite reflectance , geology , temperature gradient , submarine pipeline , structural basin , mineralogy , geochemistry , petrology , geomorphology , paleontology , source rock , geotechnical engineering , meteorology , physics
The temperature history for the BPI‐W2 well in the oil‐producing Suphan Buri Basin, central Thailand, has been investigated using different surface temperatures (T s ). Two ID models using T s values of 0°C and ∼22°C were able to fit the suppression‐corrected vitrinite reflectance (VR) values and burial peak temperatures (T peak ) in the well. The geothermal gradient averaged over 3 km is ∼54°C/km for T s = 0°C, whereas it is ∼42°C/km for T s ∼22°C. T s = 0°C is, however, considered to be unrealistic and the ∼54°C/km gradient is therefore too high. Similarly, a previously determined geothermal gradient of 62°C/km is considered to be an overestimate. The geothermal gradient of ∼42°C/km is plausible compared to other geothermal gradients onshore and offshore Thailand, although it is at the low end. This may be due to a too low suppression correction for the measured VR values. The obtained temperature history can be used to predict measured present‐day temperatures of T s ∼22°C and 77°C in the reservoir in the U Thong oilfield. The obtained temperature history associated with the geothermal gradient of ∼42°C/km seems realistic as it predicts that the onset of oil generation at 107°C will have post‐dated reservoir and trap formation in Middle to Late Miocene times.