In order to improve the expected primary recovery of nine percent of the original oil in place in the Lone Rock Sparky pool, steam flooding was chosen as an enhanced recovery process. A pilot was developed in 1984 comprising three adjoining 15 acre inverted seven spot patterns drilled on five acre spacing. There are currently 3 steam injection wells, 13 producing wells, 1 Observation well and 2 salt water disposal wells in the pilot. Steam injection was initiated November 30, 1984 into the three injection wells. Steam stimulation took place from January to July 1985 with 11 of the 13 producers receiving a steam slug either before or after being placed on production. Pilot production started March 1985. All wells were on production by July 1985. This paper presents the objectives of the pilot and briefly discusses the performance to date.
Basic monitoring techniques used at the Pilot are discussed and include bottomhole temperature measurements in selected production, injection and Observation wells. The measurement of chloride in the prcduction fluids has been a useful tool in rronitoring fluid movement within and outside the pilot area.
The Lone Rock heavy oil pool is located 18 miles southeast of the town of Lloydminster and has been producing heavy oil since 1947 (Figure 1). While waterfloods have typically been used to improve recovery from the Lone Rock pool, a relatively thick section of Sparky sand in this area was thought to be a good candidate for thermal recovery techniques. Due to the extremely low reservoir pressure remaining after 9% primary recovery, a steam flood rather than a cyclic steam stimulation was considered as the only effective thermal EOR process. An engineering study was conducted in 1983 to review the technical and economic r:otential for steam flooding the Lone Rock Sparky sand. As a result of the study, a pilot consisting of three adjoining 15 acre inverted seven spot patterns was constructed in 1984. There are currently 3 steam injection wells, 13 producers, 1 observation well and 2 salt water disposal wells in the pilot (Figure 2). To December 31, 1996 incremental recovery from the pilot was 62 656 m or 15.3% of the COIP. within the pool, at least 765 acres have been identified for potential application of steam flooding,
The Pilot objectives were:
establish reservoir production characteristics,
determine treating methods to process the crude production,
obtain operating experience with enhanced recovery facilities,
determine costs representative of continuous operations,
establish the effect of directional drilling, casing size and completion type on well production.
Objective i) includes the monitoring of primary production wells which are located adjacent to the pilot site.
Problems encountered in the pilot have included sand production, poor pump efficiencies and fluid loss outside the pilot. These are discussed in the paper.