The pdf file is incomplete. The complete journal version of this paper is available as PETSOC 91-01-01.
A conceptual reservoir flow path model for fireflood in a heavy oil reservoirwith initial oil mobility was presented in 1988 [1]. The concept offlow paths and low injection rates to enhance oil production was implemented inthe operational strategy for the Husky Tangleflags Fireflood Project in the Lloydminster heavy oil field in Saskatchewan. Canada.
Significant events in the Tangleflags Project are presented to demonstrate thebenefits of upgraded oils generated by the combustion process, and oilresaturation of the flow paths to enhance oil recovery. Incremental productionwas attributed to the fireflood process. Fireflood response was fairly evenlydistributed in the pattern producing wells. No severe operational problem wasevident compared to the typical problems associated with firefloods predicatedon a radial burn and displacement approach.
The fireflood recovery process has been tested by Husky [2,3] in the Lloydminster heavy oil fields in Saskatchewan, Canada and by others in variouscountries in the world [4]. Fireflood remains to be the most viablerecovery process for depleted heavy oil reservoirs with less than 8 m net paybut has not been demonstrated to be a commercial process in Canada. Most of thefireflood designs were predicated on a radial burn and radial displacementapproach [5,6]. Largely based on burn tube data, the air injectionrate was designed to achieve a sufficient burn rate in the reservoir todisplace and produce oil at an economic rate. Non-radial burn fronts, highcasing pressures, elevated bottomhole temperatures well damages and reducedproductions were reported to be major problems [2,4,6].
A conceptual reservoir flow path model for firefloods in heavy oil reservoirshaving some initial oil mobility was presented in 1988 [1]. Theconcept of flow paths was used to optimize the air injection rate, and theoperational strategy in the Husky Tangleflags Fireflood Project. Significantevents in the Tangleflags Project are presented to support the flow pathmodel.
The produced oil viscosities in most wells were lower than the native oilviscosities, confirming the mixing of native oil with upgraded oils generatedby the combustion process. The positive effects of fireflood were fairly evenlydistributed among the pattern producing wells. No severe operational problemwas observed compared to the problems associated with typical firefloodprojects. Incremental oil recovery was achieved by fireflood using lowinjection rates in the largely depleted heavy oil reservoir.
The Husky Tangleflags Fireflood Project was located in Section 13-51-25 W3 asshown in Figure 1. The project area had been produced on primary using 16.2 ha(40 acre) spacing since 1971. Over 120 × 103m3 of oil wasproduced from Section 13 to the end of 1983. Two primary wells, A6 and A7, wereconverted to injection wells. One injection well, thirteen pattern wells andsix offset wells were drilled and completed for this project in 1984 and 1985.The project consisted of three 12.1 hectare (30 acre) inverted 7-spot patternscompleted in the GP Formation as shown in Figure 2. Six offset wells werelocated around the three patterns to capture fugitive combustion gases.
