Interval Inversion of Wellbore Data for Characterizing Metamorphic Hydrocarbon Reservoirs

In investigating multi-mineral rocks, the nonlinear well-logging inverse problem becomes an underdetermined or at the best a very narrow type of overdetermined problem, which cannot be treated by conventional local (point-by-point) inversion methods with satisfactory accuracy and reliability. In order to determine the unknown petrophysical model composed of many parameters (i.e. volume of matrix components, water saturation, clay content, primer and secondary porosity) with no ambiguity, it is essential using a joint inversion process. The interval inversion method is a special kind of joint inversion technique, which inverts data of a greater depth interval simultaneously in a highly overdetermined inversion procedure. Having used interval inversion method with success for the case of shaly sand environments, now the efficiency of the global optimization based interval inversion method is demonstrated for the case of hydrocarbon-bearing rocks with complex lithology.