IMPROVED MATERIAL-BALANCE REGRESSION-ANALYSIS FOR WATERDRIVE OIL AND GAS-RESERVOIRS

An improved material-balance formulation is presented for determining original hydrocarbons-in-place (OHIP) in waterdrive oil and gas reserv oirs. The improved formulation reduces the number of unknowns in the r egression analysis through the definition of a combined aquifer/reserv oir expansion term (CARET). Field examples analyzed with the CARET for mulation are presented illustrating the nonunique nature of waterdrive material-balance solutions for CHIP. A method is presented for realit y checking the best-fit aquifer parameters obtained from the regressio n analysis. The CARET material-balance formulation is shown to provide several advantages over existing regression analysis techniques.