Petroleum Production Systems

Chapter 6. The Near-Wellbore Condition and Damage Characterization; Skin Effects

6.1. Introduction

Radial flow to a vertical well results in increasingly higher flow velocity near the well and accounts for the semilogarithmic nature of the pressure–distance relationship presented in Chapter 2 [Equation (2-4)]. Van Everdingen and Hurst (1949) introduced the concept of a pressure difference, Δp_s, occurring over an infinitesimal distance at the wellbore radius proportional to the skin factor, s, as in Equation (2-5), to account for a nonideal flow profile.

Mathematically, the Van Everdingen and Hurst skin effect has no physical dimension and is analogous to the film coefficient in heat transfer. When added to ln(r_e/r_w) for steady state, ln(0.472 ...