This paper reviews the development of directional drilling practices in Husky's Pikes Peak Cyclic Steam Project. A total of 66 directional wells have been drilled since 1983 resulting in significant time and cost savings. The average spud-to-spud time has dropped from 123 hours in 1983 to 13 hours in 1987 compared to 100 hours for conventiona1 vertica1 wells.
Aggressive build rates (6 °/30 m) have been used to increase horizonta1 displacements and decrease overall hole angle, reducing the number of drilling locations necessary. Tabular and graphical data are presented which support these achievements.
Pikes Peak is located 42 kilometers east of the city of Lloydminster in the province of Saskatchewan. The field was initially developed in the late 1970's on 40 acre spacing for primary development of the GP sand. Logs from these wells identified a Waseca channel sand at a depth of 500 m with an average net pay of 12 m. The reservoir is a very clean unconsolidated sandstone with 1-5 Darcy permeability, 30-33% porosity and an initial oil saturation of 85%. Efforts to primary produce the zone were unsuccessful due to the low gravity (11 ° API) and high viscosity (25,000 cp) of the oil.
Development for thermal recovery started in 1980 with the drilling of 6 vertical wells. Favourable results under cyclic steam stimulation resulted in 40 vertical wells being drilled up to 1983. The development strategy, using 7-spot patterns and one hectare per well spacing, made pad operations attractive, and in 1983 7 wells were directionally drilled from a single pad site. A total of 66 directional well shave since been drilled in Pikes Peak with an estimated 35 locations remaining. Figure I shows the project as it exists today.
The following discussion presents the planning, implementation and results of a 14 well pad drilled in 1987. Historical data is used to support the reasoning wherever possible.
The area, developed in 1987, is shown in Figure 1 and is adjacent to the existing wells. Although a conservative 4 °/30 m maximum build rate was used in previous directional drilling, a 6 °/30 m build rate from a 90 m kick-off depth was planned to achieve a horizontal displacement of 350 m at the pay depth of 500 m TVO. Using this criteria, 14 targets could be drilled from a single pad whereas only 10 could have been reached with the original build rate. The aggressive build rate thus saved the cost of building an additional pad and all the associated piping and facilities. Existing steam and production facilities were capable of handling this number of wells thus minimizing capital expenditure. A straight line pad configuration with wells on 6 m centers is optimum for 14 wells as it minimizes well path interference and surface lease area. The drilling pad area of 1.3 hectares is reduced to 0.8 hectares for production operations.
A detailed time analysis of the 52 previously drilled directional wells was prepared from the rig's tour reports.