Development of the Pelican Lake Area: Reservoir Considerations And Horizontal Technologies
Authors: Fossey J.P. , Morgan R.J. , Hayes L.A. 
Published: March 2010

CS Resources Limited is a leader in reservoir exploitation using horizontal well technologies. This paper addresses reservoir considerations and discusses the drilling cost and reserve improvements achieved over the last seven years. It also exposes, the use of horizontal well innovations currently, being pursued in the Pelican Lake region. The 1995 Development Drilling program in the Pelican Lake area included a multi-arm horizontalwell utilizing the Lateral Tie Back System (LTBS). The system dramatically increases the, reservoir exposure over conventional horizontal well technology while maintaining liner integrity throughout the horizontal network. Using the LTBS, CS Resources Limited drilled a horizontal well ith three lateral arms. This well provides almost 4,000 m of reservoir exposed to slotted production liner.

Project Background

The Pelican Lake property, located 280 km north of Edmonton in the Wabasca region of Alberta (Figure 1), covers an area of 23,000 ha. The discovery well, Gulf Pelican 6-9-81-22W4M, was drilled in 1978. Exploration work conducted to date at the Pelican Lake property has identified two petroleum bearing horizons known as the "Wabiskaw formation" and the "Grand Rapids known formation."

FIGURE 1: Western Canada-Pelican Lake Region. Illustrations available in full paper.

In October 1987, CS Resources entered into a farmout and option agreement with Gulf Canada covering 15,000 ha in the Pelican Lake area. Prior to CS Resource's acquisition of the subject lands, more than $100 million had been expended in the Pelican Lake area. From 1980 to 1986, approximately 100 vertical and deviated wells were drilled. A variety of EOR processes were tested including water flooding, cyclic steam stimulation, steam flooding and fire flooding. All of these operations have since been suspended.

Reservoir

The Wabiskaw formation contains approximately 160 million cubic metres of 14 degree API gravity crude oil in place and has yielded a primary recovery factor in the order of 5 %. The viscosity of the crude oil is between 600 and 1,000 centipoise at 20 ºC in the actual area developed by CS Resources (T81-R22W4). The formation sand has an average porosity of 26% and an average horizontal permeability of 3 Darcies. Although this shallow formation (400 m) exhibits some excellent reservoir characteristics, the relatively thin pay zone, capital costs for the required infrastructure and high operating costs have resulted in this project being uneconomic employing conventional vertical well technologies [Reference (2)].

The overlying Grand Rapids formation, which occurs at a depth of 225 m, is thicker than the Wabiskaw and contains approximately five hundred million cubic metres of bitumen in place. However, the heavier eight degree API oil, which is characteristic of much of Canada's oil sands occurrences, will require the introduction of a thermal enhancement program.

Geology

The Pelican Lake area lies in the middle of the Wabasca oil sands deposit. The Wabiskaw sands comprise part of the Mannville group of Lower Cretaceous age and were deposited as a marine blanket sand. The Wabiskaw sands contain the members "A," "B," and "C." The "A" sand is the primary heavy oil bearing member and it is overlain by theabiskaw A claystone.