Application of Pre-Stack Inversion to a Complex Reservoir Prediction: a Case Study in LG34 Area, Tarim Basin

The Donghe Sandstone formation (DS fm. for simplicity) presents an excellent thin condensate gas reservoir in LG34 well area, Tarim Basin. Unfortunately, drilling results show that the reservoir is thin, deeply buried (below 5000m) and mix lithologies. Pre-stack inversion and fluid identification is implemented in this area. The feasibility and validity of pre-stack inversion for this kind of reservoir is tested, since that application of pre-stack inversion in this area is for the first time. A new rock physics model is used for estimating rock velocities and elastic attributes, and cross-plots of Poisson's ratio (σ) again LambdaRho (λρ) is found to be more favorable for lithofacies identification. Then, pre-stack inversion which uses seismic data with careful amplitude processing is performed to predict the reservoir. The inversion results agree and tie with most wells, suggesting that the pre-stack inversion is viable process for this complex lithological reservoir prediction in the area.