This paper presents the general design and operations overview of the Silverdale Wet In Situ Combustion Pilot. The design of the pilot was based on a reservoir simulation of the Sparky Sandstone using reservoir and burn tube data. The pilot was an inverted nine spot pattern which was ignited in August of 1973 and terminated in December of 1980.
In the operation of the Silverdale Wet In Situ Combustion Pilot, unique production problems associated with the combustion process were encountered. These problems were pumping, handling and treating of the viscous gasified sand laden emulsions and severe corrosion.
The reservoir performance indicates that large oil recoveries are possible, however, the lifting of the reservoir fluid will have to be improved to make the combustion process economical.
The Lloydminster area of Alberta and Saskatchewan contains an estimated 13 × 109 m3 of oil in place (Reference 2). The reservoirs capable of production, generally have primary oil recoveries of 5 to 7 per cent of oil in place. The secondary recovery techniques, such as waterflooding, can increase the recoveries from these reservoirs to as much as 9 to 12 per cent of oil in place. Tertiary recovery techniques employing combustion or steam have shown substantially higher oil recoveries, however, until the late sixties, these tertiary methods were largely untested in the Lloydminster area.
Murphy Oil Company Ltd. has roughly 300 × 106 m3 of heavy oil in place in the Lloydminster area. Feasibility studies were conducted to determine if tertiary recovery techniques were applicable to some of the heavy oil pools. The Silverdale South Sparky pool was chosen as the study site for the combustion process.
The Silverdale South Sparky Pool was cored for fluid and reservoir data. This data was then used in a combustion tube test to determine parameters of the combustion process. The reservoir was numerically simulated using the reservoir and combustion tube data. The reservoir simulation indicated that large oil recoveries were possible from the Silverdale pool using the combustion process. An application to construct and operate a wet in situ combustion pilot was approved by the Saskatchewan Government in February, 1973.
The Silverdale Wet In Situ Combustion Pilot was an inverted nine-spot pattern which enclosed an area of 16.2 hectares. The pilot was completed in the Sparky sandstone formation wh1ch is about 5.5 m thick and 564 m deep. The pilot was located 16 km south by east of Lloydminster, Saskatchewan. The location map shows the heavy oil areas on Figure 1. The South Cold Lake and Lloydminster areas are shown in Figure 2.
The heavy oil pools in the Lloydminster area are generally found in the Mannville Group of the Lower Cretaceous Period. The Mannville Group, about 170 m thick, is composed of bar and channel sands, consisting of interbedded shales, sands and siltstones. These sands can be divided into nine correlateable formations; Colony, McLaren, Waseca, Sparky, General Petroleum, Rex, Lloydminster, Cummings and Dina.