Simulation Of A Directly Miscible Vertical Dlisplacement Hydrocarbon Solvent Flood

Abstract

Abstract A simulation of the performance of the hydrocarbon miscible flood in the Rainbow Keg River ‘E’ Pool is presented. The reservoir has been under continuous hydrocarbon solvent injection since June 1972. The direct contact miscible flood is being conducted downward in a maximum oil column of172 m. A review of the geology, rock and fluid characteristics is given. The pool was produced on primary depletion from July 1966 to August 1967, and shut-in from August 1967 until the solvent injection commenced in 1972. The black oil model history match of the primary depletion and shut-in is presented. The hydrocarbon solvent flood performance was modeled using J.S. Nolen and Associates' Miscible Vectorized Implicit Program. The simulation study provided an estimate for the efficiency of the hydrocarbon solvent flood of the ‘E’ Pool. Introduction The Rainbow Keg River ‘E’ Pool was discovered in March 1966. The discovery well penetrated a small biohermal pinnacle reef of Middle Devonian age located in the Rainbow Lake Area of Alberta (Fig. 1). The pool began production under primary depletion in June 1966 and was shut-in in August 1967. Due to the initial in-availability of miscible fluid the pool was shut-in for 56 months until May 1972 when injection was commenced. The solvent injection commenced in May 1972. Solvent breakthrough occurred in the two producing wells two to three years later. The third or last well was drilled and completed in ‘E’ Pool in 1978. This well produced solvent immediately even though it was placed in an area of the pool opposite to the two former wells. The field solvent-oil ratio in late 1982 was 650 m3/m3 with a cumulative oil production of approximately 1100 × 103 m3 or 33% of the original oil-in-place (OOIP). This paper discusses the rock and fluid properties. It also describes the reservoir simulation history match of the primary and solvent injection periods. Following the history match the future performance of the reservoir was predicted. History The discovery well of Rainbow Keg River ‘E’ Pool was the 7-18-109-7 W6M well (Fig. 2). It was spudded on 1966-02-22 and drilled to a depth of 2018 m penetrating 172 m of oil-bearing Keg River Reef. The well was completed 89.8 to 83.7 m above the original oil/water contact (AOOWC) in April 1966 (Fig. 3). The pool went on production in July 1966 and continued until August 1967 when it was shut-in. The production data are shown in Figure 4. The pool produced 51 × 103 m3 of oil with no water. The gas to oil ratio (GOR) was very erratic. The initial pool pressure was 17 408 kPa at the mid-point of the perforations (MPP) as shown in Figure 5. There were four pressure surveys during the primary production period. The MPP pressure decreased 3524 kPa to the end of the primary depletion. The pressure was recorded eleven times during the shut-in period. The MPP pressure increased 795 kPa during the shut-in period from September 1967 to March 1972.