FLUID SUBSTITUTION IN SHALY SAND RESERVOIRS

Abstract

Gassmann fluid substitution predicts different elastic properties at different fluid scenarios. It is an excellent tool for an interpreter to model seismic anomalies. In this report. I have discussed its application and pitfalls in its application. It is available in many softwares worldwide, however its application requires good understanding of the methodology. I have discussed about the methodology of Gassmann's equation. I have also discussed workflows and codes for performing fluid substitution in shaly sand reservoir using Matlab software. Traditional fluid substitution gives absurd results when applied to laminated sands. The interpreter needs to have a prior knowledge of the model, whether it is shaly sand or laminated reservoir. Using data from Kaveri Basin, I have modelled Gassmann fluid substitution for shaly sand reservoirs. I have correlated different parameters to Show their behaviour for real data. In order to show it, I have discussed about velocity variation against water saturation. I have also included well section for the given data using PETREL software. Further I have enclosed the Matlab code for Fluid Substitution for shaly sand reservoirs in the appendix.