Although this ensured the accuracy of the wavelet, the reflectivity of the seismic data was also corrected using a simultaneous reflectivity colour correction. A wavelet was extracted using a least squares simultaneous extraction from all of the calibrated logs. A log balancing technique was developed to compensate for logging errors due to tool calibrations, washouts and fluid saturations as defined by the geological work. The detailed geological modelling study was the source of corrections required for varying vintages of sonic and density log information, core porosity information and structural information. On conventional seismic, the reef top could only be interpreted by inference due to tuning from other seismic events. Lithology Based InversionĪ lithology based seismic inversion was conducted on the 115,000 trace 3D data volume to enhance confidence in the position of the interpreted reef edge. Reserve additions and increased daily production resulted. Subsequent vertical and horizontal drilling results substantiated the concept of clean reef edge oil. Seismic interpretation delineated potentially undrained reserved which were identified as drilling targets. Vertical and lateral resolution limits for the reef edge were exceeded. Minimizing environmental impact by utilizing existing access and avoiding Forestry sample plots were concerns for the design and acquisition of the program. In January of 1992, Home Oil acquired a 23.64 square kilometre 3D seismic program to delineate the reef edge so as to mitigate drilling risk for potentially trapped updip oil. The geologic study identified potential for attic oil and possibly clean reef edge oil.
The resultant geologic perspective enhanced the knowledge of the reservoir and identified further opportunities. The reef was subdivided into different layers and mapped accordingly. In 1990, Home Oil initiated a computer based geologic reservoir modelling study consisting of information from 485 wells to understand more fully the reservoir architecture of the field. Water flooding started as early as 1965, miscible flooding with an ethane rich solvent commenced in two phases in 19. The average field watercut is 86 percent. Watercuts vary by geologic zone and geographic area. The unitized lands have estimated 1,413 Mmbbls oil in place and produced cumulatively 540 million barrels to date with daily production rates currently at 27,000 bbls/day, 37mmcf/day gas and 130,000 bbls/day of water. The field was unitized in the Beaverhill Lake zone in 1963 and subsequently revised in 1983. The field was discovered in 1957, two months after the discovery of Virginia Hills. Home Oil is the operator of Swan Hills Unit #1 with approximately 18% working interest. The Swan Hills Unit #1 lies approximately 200 kilometres northwest of Edmonton, Alberta, Canada along the trend of several long-standing producing fields from the Swan Hills formation.