Experimental Evidence of the Applicability of Colebrook and Borda Carnot-Type Head Loss Formulas in Transient Slug Test Analysis

Abstract

Radius changes along the flow path inside a well can have a substantial nonlinear impact on head responses to a slug test. The present paper investigates the applicability of head loss formulas rooted in steady-state pipe hydraulics to account for minor and major head losses in transient slug test analysis. Such nonlinear head losses, which frequently occur when using a packer for test initiation, have not systematically been investigated before. Packer-internal turbulence is accounted for based on Colebrook’s formula, while minor head losses originating at the inlet and outlet of the packer are treated by Borda Carnot-type head loss formulas. The analysis of a specifically designed set of 12 slug tests provides extended experimental evidence of the applicability of these nonlinear head loss formulas when accounting for well bore-internal turbulence and minor head losses in transient slug test analysis.