Formation-rate-analysis technique: Combined drawdown and buildup analysis for wireline formation test data

The formation-rate-analysis (FRA(SM)) technique is introduced. The techniqu e is based on the calculated formation rate by correcting the piston rate w ith fluid compressibility. A geometric factor is used to account for irregu lar flow geometry caused by probe drawdown. The technique focuses on the fl ow from formation, is applicable to both drawdown and buildup data simultan eously, does not require long buildup periods, and can be implemented with a multilinear regression, from which near-wellbore permeability, p*, and fo rmation fluid compressibility are readily determined. The field data applic ations indicate that FRA is much less amenable to data quality because it u tilizes the entire data set.