Analyzing Sensitivity of Elastic Properties on Lithology and Fluid Change, an Example from Malay Basin

Understanding the sensitivity of different elastic properties towards changes in lithology and fluid type is a crucial information in hydrocarbon exploration and development. Fluid substitution was conducted on Well X in Malay Basin using the Gassmann’s Equation and subsequently, the elastic property of both measured well data and fluid substitution scenarios were calculated. Cross-plots of relevant elastic property was generated to analyze the response. The best elastic property for lithology differentiation is the Poisson Ratio and Labdha-Rho/MuRho. Shear Impedance, Shear Modulus, Young Modulus and Mu-Rho are also good indicators of lithology. The elastic properties that are most sensitive towards changes in fluid type is the Lambda-Rho, Labdha-Rho/Mu0Rho, P-Impedance and Poisson Ratio. Cross-plots between Vp, density and Bulk Modulus can differentiate between oil-sand and gas-sand at 100% saturation. This understanding on the sensitivity of the elastic properties towards lithology and fluid fill will allow for future seismic-based inversion to be conducted in and surrounding this field in Malay Basin.