A Simple Method to Estimate Interwell Autocorrelation
Jorge Oscar de Sant’ Anna Pizarro, Larry W. Lake, 1999. "A Simple Method to Estimate Interwell Autocorrelation", Reservoir Characterization—Recent Advances, Richard A. Schatzinger, John F. Jordan
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The estimation of autocorrelation in the lateral or interwell direction is important when performing reservoir characterization studies using stochas-tic modeling. This paper presents a new method to estimate the interwell autocorrelation based on parameters, such as the vertical range and the vari-ance, that can be estimated with commonly available data.
We used synthetic fields that were generated from stochastic simulations to provide data to construct the estimation charts. These charts relate the ratio of areal to vertical variance and the autocorrelation range (expressed variously) in two directions. Three different semivariogram models were considered: spherical, exponential, and truncated fractal.
The overall procedure is demonstrated using field data. We find that the approach gives the most self-consistent results when it is applied to previously identified facies; moreover, the autocorrelation trends follow the depositional pattern of the reservoir, which gives confidence in the validity of the approach.