Horizontal Steam Injectors in the Kern River Field

Abstract

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 187258, “Design and Operational Experience With Horizontal Steam Injectors in the Kern River Field, California, USA,” by R.S. Buell, SPE, R. Gurton, J. Sims, SPE, M. Wells, G.P. Adnyana, M. Shirdel, SPE, C. Muharam, T. Gorham, SPE, E. Riege, and G.B. Dulac, Chevron, prepared for the 2017 SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA, 9–11 October. The paper has not been peer reviewed. A horizontal-steam-injection pilot project has been under way for the last 4 years in the Kern River heavy-oil field in the southern San Joaquin Valley of California. This project was designed to address a series of learning objectives for horizontal steam injection in a mobile heavy-oil reservoir. These objectives included mechanical integrity and operability, steam conformance control, steam-flow profiling, and reservoir response and long-term operability. Introduction While documented cases of continuous and cyclic horizontal steam injection in mobile heavy oil exist, these have not led to large-scale economic development of thermal heavy oil. Most thermal, mobile, heavy oil is currently produced with vertical steam injectors. The Kern River Field is a good example of this recovery technique. The primary heavy-oil reservoir in the field is 300 to 1,300 ft deep, with a reservoir thickness of up to 900 ft. During the last 50 years, most of the field has been developed with continuous vertical steam injectors, with typical pattern spacing being 2.5 acres. The pilot area is approximately 12 acres and is on the northwest flank of the field. The pilot injected steam into sand that has an average thickness of 22 ft across the pilot area. The pilot’s original configuration included two horizontal injectors, nine vertical producers, and 12 temperature-observation wells (TOWs). Of the 23 wells in the pilot area, five were existing wells and the remainder were new drills. Two types of TOW were used in the pilot: (1) injector TOWs, which have a short offset of less than 40 ft from the horizontal injectors and are intended to assist in understanding injector steam conformance, and (2) reservoir TOWs, which are more than 50 ft from injectors and producers and are intended to help understand far-field reservoir response. The pilot used horizontal continuous steam injection but is different from a bitumen steam-assisted-gravity-drainage application in that the heavy oil is mobile and will flow at reservoir conditions. Another important difference is that a horizontal producing well has not been placed 15 to 25 ft under the horizontal injector. In fact, vertical producing wells were used in the pilot area offset 140 ft from the horizontal injectors.