Targeted Steam Injection Using Horizontal Wells with Limited Entry Perforations

Abstract

Abstract Limited-entry perforations have been used in vertical wells in both California and at Imperial's Cold Lake field as a method for distributing steam to different zones. The technology relies simply upon designing the number, size and placement of the perforations so that critical or choked flow occurs across the perforations during steam injection, and steam exits the well with the desired distribution. This paper describes an experimental horizontal well where this same technology was used to replace ten vertical injection wells with a single horizontal well. The well was located between rows of vertical wells in reservoir that had been subjected to more than ten years of operations under cyclic steam stimulation. The limited-entry perforations enabled steam to be targeted at the cold regions of the reservoir. A more typical completion such as a screened or slotted liner would not have provided any control over the placement of steam in the reservoir. The 1000 m long liner was cemented in place with a completion design consisting of only 28, 3/8 inch diameter perforations which were drilled through the casing and cement. The design injection rate for the well was 2000 to 3000 m3/day of 70% quality steam. This paper presents an assessment of the performance of the well based on theoretical calculations, measured injection pressures and rates, and 3D seismic imaging.