Study and Application of “Sweet Spot” Prediction Technique in the Reservoir Reconstruction of Gas Reservoir with Low Permeability in East China Sea

The sandstone reservoirs in Xihu Sag are buried deeply and the gas reservoirs with low permeability account for a large percentage.In order to develop effectively,the reservoir reconstruction should be conducted.Due to the characteristics of strong heterogeneity and rapidly lateral change,how to identify the sweet spot area is a key to the success of reservoir reconstruction.Based on the analysis of the geological origin of sweet spot,the elastic parameters which are sensitive to lithology,physical properties and gas-bearing property were optimized by the analysis of petrophysical characteristics.And then the sensitive attributes determined by pre-stack synchronous inversion were used to predict the distribution characteristics of sandstone thickness,physical property,gasbearing and brittleness index.The first and second class of sweet spot areas can be identified by the combination of geological and engineering dominance attributes and can provide important reference to well location design of horizontal multi-staged fracturing.