Huff 'n' Puff Recovery Technique on Waterout Horizontal Wells

摘要

After the bottom water breaks into a horizontal well, the traditional way to recover the left oil above the horizontal well is to plug in the section below water level (the horizontal section) and re-perforate in the vertical section. However, this practice loses the advantage of horizontal wells. This paper proposes a Huff and Puff recovery technique for horizontal wells after water breakthrough and this technique utilizes the whole horizontal well instead of just the vertical section to further the oil recovery. Huff and Puff process is a cyclic gas injection process often used to recover attic oil, which involves three steps: gas injection, shut-in and production. Through a parametric study, the important control parameters towards a successful Huff and Puff recovery project are identified. In the analysis, we consider the impact of hysteresis on modeling the recovery processes through a historydependent- modeling method taking into account of the hysteresis of both relative permeability and capillary pressure. The results indicate that ignoring the hysteresis can overestimate the recovery predictions up to 16%.