Senlac, The Forgotten SAGD Project

Abstract The Senlac SAGD (Steam-Assisted Gravity Drainage) project is Saskatchewan, Canada, does not have the same name recognition as its much bigger brothers in the Alberta Oil Sands but it certainly deserves to be known better. Senlac was the first industrial SAGD project in Canada back in 1997 and since then it has been the site for other technological innovations such as the use of solvent in addition with steam to increase recovery and reduce the Steam Oil Ratio, as well as the testing of wedge wells – wells drilled between SAGD well pairs to benefit from the heat remaining in the reservoir. The reservoir in Senlac is the Dina-Cummings of Lower Cretaceous age and is much smaller than the McMurray formation which is the site of most of the large-scale oil sands project but the oil is only 5,000 cp thus it is mobile at reservoir temperature. This is a significant difference which allows well pairs to achieve excellent production and recovery even though reservoir thickness is only 8-16 m, well below the standard cut-off for SAGD. The presence of bottom water under parts of the field is an added challenge to the operations. The paper will present the field characteristics and production performances as well as the main technological developments such as the Solvent Added Process and the use of wedge wells. The paper will present a complete case study of a SAGD project in a heavy oil reservoir where oil is mobile. Most SAGD project so far have been conducted in bitumen but the paper will show the potential for this technology in thinner and smaller reservoirs.