Abstract
This paper will detail the technological evolution of drilling and completion practices utilized to optimize economic development of the Slave Point carbonate platform specifically in the Evi and Otter fields in northern Alberta. The Slave Point platform was initially targeted for conventional production via vertical wells in the early 1980s.
Success was marginal due to the unpredictability of localized porosity development. As a result, full scale commercial development of this resource was deemed uneconomic due to poor reservoir quality. More recently, however, horizontal drilling and multistage fracturing technology has allowed operators to open up lower porosity horizons to improve flow capacity, improve recoveries, and allow for commercial development from zones previously deemed as uneconomic.
The Slave Point has a greater thickness and is less permeable than other tight rock plays in Alberta such as the Cardium and Viking. It produces high-quality, light oil with low water and solution gas production rates. Despite high estimates of original oil in place of approximately 3 to 10 MMbbl per section, horizontal well rates are still challenged due to lower permeability through the pay section. In this regard, the continued deployment of innovation and technology has been critical in improving well production performance, compressing project costs, and ultimately optimizing project economics.
The focus of this paper is solely upon one of the major Slave Point operators who has drilled 49 horizontal wells accounting for 200,000 m (656,000 ft) drilled and 1,350 fracture stages in the Evi and Otter Slave Point fields since 2008. This operator has continually deployed advancing technologies to improve project economics. The information will be presented in terms of the influence of technology on well design, the optimization and deployment of the various technologies, and the demonstrated improvement on productivity and reserve recovery. The discussion will focus on three development phases outlined below, which highlight the progression from vertical to horizontal technology.
Vertical Appraisal
Single Lateral Development
Dual Lateral Development
The case studies presented will clearly demonstrate the production impact upon the utilization and application of these technologies. The methods and lessons learned through the use of dual laterals, open hole junctures and open hole multistage systems can be applied to other unconventional formations.
