4D Chi Significance - Enhanced AVO Imaging of 4D Fluid and Pressure Changes

We introduce a new technique to compensate for angle-dependent noise, in the analysis of 4D AVO data. AVO projections are a valuable tool for imaging production related pressure and fluid changes across a reservoir, but commonly have issues with high noise levels, and fully decoupling pressure and fluid effects from each other. Both issues can be addressed by a new approach that compensates for angle dependent noise. A trend of 4D noise as a function of angle is first extracted from the data and amplitudes are then normalised against this trend. Fluid and pressure projections clipped below the noise level are generated. The method improves the separation of pressure and fluid signals, enabling 4D attributes to be used with greater confidence.