Basin modelling: Applications of sensitivity analysis

Abstract

Geological processes related to petroleum generation, migration and accumulation are simulated with mathematical/computer models based on geological principles. Sensitivity analysis is a comprehensive examination of how geological, geophysical and geochemical parameters influence the reconstructions of geohistory, thermal history, and hydrocarbon generation history. Using a 1-D fluid flow/compaction model we examine the effects of some of the commonly used parameters (such as depth, age, lithology, porosity, permeability, unconformity, eroded thickness and erosion time, temperature at sediment surface, bottom-hole temperature, present-day heat flow, thermal gradient, thermal conductivity, and kerogen type and content) on the evolution of formation thickness, porosity, permeability, pressure with time and depth, heat flow with time, temperature with time and depth, vitrinite reflectance ( R 0) and TTI with time and depth, the “oil window” in terms of time and depth, and the amount of hydrocarbons generated with time and depth. The sensitivity variations are helpful: (1) to understand the importance of the parameters in the reconstructions of geohistory, thermal history and hydrocarbon generation history in sedimentary basins; and (2) to provide knowledge of resolution capabilities of models with respect to input data, input parameters and intrinsic assumptions so that basin evolution models are more effective in hydrocarbon exploration.