Field Observations of In Situ Combustion In a Waterflooded Reservoir In the Kimsella Field

Abstract

Abstract An in situ combustion pilot project was conducted in the Viking Kinsella Wainwright B pool (oil gravity 20 ºAPI) from 1983 to 1987. Air, enriched air, and oxygen were injected into the waterflooded reservoir during two phases of the project. In Phase I, air was the injection gas; in Phase 2. oxygen enriched air and oxygen were the injection gases. Following the termination of the pilot, an analysis of the project was performed. This paper will describe the operation of the pilot and present the results of the project. The principal conclusion is that the pilot did not sustain combustion at high temperatures. Instead, it generated an oxidation zone in which the predominant reactions were those of low temperature oxidation. Even so, incremental oil was produced during Phase 1. Incremental recovery was estimated to be 1.2% of the Original Oil In Place (OOlP) in Pattern 59. Had Phase 1 not been terminated, incremental recovery could have reached 7% of the OOIP. Phase 2 was characterized by production of oxygen, shut in wells, and other operating problems. These problems were primarily a result of unfavourable oxidation kinetics with the Kinsella oil at high oxygen concentrations. Introduction The Viking Kinsella Wainwright B pool was discovered in 1973. The field is located about 100km southwest of Lloydminster, Alberta. Iit was developed on 8 ha spacing and was placed on waterflood in 32 ha inverted nine-spot patterns in 1976. Ultimately, the waterflood had more than 240 production wells and 80 injection wells, and covered 10 sections of land. The reservoir characteristics of the pool are presented in Table 1. In the early 1980's a reservoir study concluded that recovery from the Wainwright B pool would be in the order of 22% of the original oil in place. To discover a process that would increase the recovery, various enhanced and thermal recovery methods were evaluated. The evaluation suggested that the most suitable process for this reservoir would be in situ combustion. As a result, a pilot project was designed to test the applicability of combustion in the Viking Kinsella Wainwright B pool. The Kinsella B in situ combustion pilot was initiated in 1983 and was terminated in 1987. Pilot Description The Kinsella B in situ combustion pilot was located in the TABLE 1: Kinsella B in situ combustion pilot reservoir and fluid characteristics. Table available in full paper. southeast quarters of 2-24-48-9W4M within Waterflood Pattern 59 (Figure 1). This location was chosen because the area represented the most advanced region of the waterflood and commercial combustion would be applied in the latter stages of waterflood operations. In addition, the formation in this region exhibited favourable reservoir characteristics basis of design for the pilot was presented by Dugdale et al.(1). An air injection well was drilled at 2A-24-48-9W4M in February 1982. It was placed on production for a few months to remove some of the near wellbore oil and thereby improve initial injectivity. Two temperature observation wells, BO-1 and BO-2, were drilled 15m west and 20 m northwest of the injector.