Managing Exploration Risk Using Basin Modeling
Economic risk analysis requires a well's dry-hole probability and a probability distribution of type and volume of recoverable hydrocarbons. Today's world-wide exploration needs methods that can accommodate a wide variety of data quality and quantity. Monte Carlo methods are commonly used to compute volume distributions and dry hole probability by multiplying probabilities of geologic risk factors such as source rock richness, migration loss, seal effectiveness etc. assuming that these are independent parameters. This assumption however is not appropriate because they represent interdependent physical processes that should be treated by an integrated system.
Basin modeling is a tool for assessing exploration risk by simulating the interdependent processes that lead to hydrocarbon accumulations. Advanced 2-D and 3-D basin modeling can treat occurrence, type, and volumes of hydrocarbons. These models need many parameters that individually may have great uncertainties, but a calibration against available data may reduce their uncertainties significantly and therefore may quantify risk. Uncertainty of thermal and source rock parameters is evaluated by applying simple and fast 1-D tools to individual wells. Calibration of pressure and temperature data as well as occurrence and type of known hydrocarbon accumulations with 2-D tools evaluates uncertainty between wells along geologic cross-sections. Individual prospect risk is finally determined y the uncertainty of local parameters within the calibrated model, as for example seal effectiveness or fault permeability.
AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California