Effect of the number and length of zonal isolations on pressure behaviour of horizontal wells

Abstract

Horizontal wells with multiple zonal isolations have become a common completion technique in the oil and gas industry. Sand problems, damaged zones, and water or gas coning are the main reasons for using isolators to sustain or improve oil and gas recovery. However, they have certain effects on pressure behaviour of horizontal wells.This paper introduces new analytical models for studying the effect of this completion technique on pressure behaviour of horizontal wells with multiple isolated zones. These models have been derived based on the assumption that reservoirs can be divided into multi-subsequent segments of producing and non-producing intervals. Based on the pressure and pressure derivative, the models can be used to estimate the impact of isolators on the pressure behaviour. This impact can be seen in the early time flow regimes such as early radial, linear, and second radial for long isolators or pseudo-spherical flow for long isolators in short wellbore. The effects of the number and length of isolators have been investigated for wells having different lengths.