Abstract
Numerical basin modeling simulators have been widely applied to petroleum exploration in recent years. Based on the observation and interpretation of the objective sedimentary basin, a geological conceptual model is constructed. The conceptual model is converted into input data for the simulator. When simulated results are consistent with the observation, the simulation is considered to be pertinent. The objective of the present study is to discuss the effects of heat-flow history and erosion on the vitrinite reflectance simulated by the one-dimensional maturity simulator “MATOIL®”.
Recent and great changes in heat-flow history can be detected easily. Measured vitrinite reflectance scatters even at the same maturity level. Quantitative estimation of the heat-flow history is restricted by the reflectance scatter. Particular attention should be paid to the fact that different heat-flow histories by which almost the same present reflectance is simulated may provide different reflectance evolutions.
An unconformity was observed between the Lower Oligocene and the Pleistocene to Pliocene (?) in the Well MITI Goto-nada. At the depth of the unconformity, vitrinite reflectance does not change significantly. Based on the reflectance simulation, the eroded sediment is estimated to be thinner than the present deposit on the unconformity.
The present study shows that there may be plural conceptual models which give the simulated results consistent with the present observation, however, these conceptual models may show different maturation and petroleum generation histories. From the viewpoint of petroleum exploration, the numerical simulation should be attempted repeatedly using possible conceptual, models.
