Determination of partial penetration skin of horizontal well

Abstract

Several analytical solutions have been developed for predicting the inflow performance relationship (IPR) for horizontal wells. However, the horizontal well does not always fully penetrate across the reservoir. When it penetrates only a part of the reservoir, it causes some degree of flow restriction, creating extra pressure loss. This additional pressure drop is known as skin of partial penetration or limited entry, Spp. The pseudo steady state solutions have been presented for determining the partial penetration skin. Three simplified equations namely, (1) Joshi et al., (2) Babu & Odeh, and (3) Goode & Kuchuk, are available for calculating the productivities of the horizontal wells for single-phase flow. The differences between the three methods are their mathematical and the boundary conditions used. Another tool to determine the productivities is using PROSPER. There are two methods available: Babu & Odeh and Goode & Kuchuk. The pressure drop caused by partial penetration obtained from the software can be use to compute partial penetration skin. This study aims to determine skin factor due to partial penetration using the reservoir simulation in order to compare with the values determined from these analytical equations under different well and reservoir conditions. The simulation results indicate that three main parameters affecting the skin factor are length of well, thickness and anisotropy of the reservoir. The most accurate method for determining partial penetration skin factor is Goode & Kuchuk analytical equation compared with the skin factor obtained from Eclipse 100 and the least is Goode & Kuchuk available in PROSPER.