An innovative technique for determining residual and current oil saturations using a combination of Log-Inject-Log and SWCT test methods: LIL-SWCT

The LIL method has the advantage of being able to generate a vertical fluid saturation profile throughout a logged interval, but suffers from its strong dependence on porosity assumptions. Subsequently, any deviation between assumed porosity and actual porosity will result in a deviation between measured Sor and true Sor. By comparison, the SWCT test method is independent of porosity, but cannot detect vertical variations in Sor.The complimentary nature of these two test methods, as well as their operational reliance on fundamentally different principles, make them ideal candidates for a hybrid testing program to measure Sor with a high degree of quality assurance. As well, combining the LIL and SWCT test methods in a single testing program offers a novel approach to measuring Soc. The details and mathematical derivation of the theory behind the measurement of Sor and Soc via this hybrid approach are presented in this paper.