Modelling Coal Maturity in a Tertiary Delta: The Mahakam Case Study (Indonesia)
BURRUS, J., and E. BROSSE, Institut Francais Du Petrole, Rueil-Malmaison, France, and J. L. OUDIN, Tour Total, Paris, France
The Mahakam delta is a major petroleum province that produces both oil and gas, generated from continental organic matter. This paper shows how the use of thermal/geochemical modeling approach permits discussion of the history of subsurface temperatures, which have been influenced effectively by various geological conditions:*laterally variable basement heat flow varying, up to 50% over a distance of less than 80 km,*convective cooling due to regional water discharge, linked with a very recent uplift of sandy aquifers, responsible for a 10-15 degrees C cooling at depth,
*considerable diffusive cooling due to sedimentation rates as high as 1000 m/Ma.
The discussion is based on two-dimensional computations of the thermal history and kinetic modeling of maturity based on IFP's finite difference TEMISPACK software. Observations used to constrain the geological hypotheses are:
*corrected subsurface temperatures (DST and BHT),*published palaeothermal mineral indications (fluid inclusions, illite/smectite ratio),*transformation ratio of the kerogen,*salinity of fluids.*experimental yield of Rock-Eval pyrolysis.
We investigate in particular, through a sensitivity analysis, the robustness of parameter calibration against uncertainty of observations.
AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)