Increasing Cold Lake Recovery by Adapting Steamflood Principles to a Bitumen Reservoir

Abstract

Abstract The Cold Lake project, located in Alberta, Canada, is the world’s largest heavy oil in situ thermal development, with production of about 24,000 m3/d (150 kB/d) of oil from more than 4500 wells. In 2009, Cold Lake produced its one billionth barrel (160 million m3) of heavy oil. The world class Cold Lake hydrocarbon resource is characterized as a bitumen deposit, featuring in situ viscosities in excess of 100,000 mPa-s. Early depletion plans envisioned a thermal recovery process similar to the steamflood technologies employed to recover heavy oil in California’s San Joaquin Valley. The order of magnitude difference between Cold Lake and California in-situ viscosities, however, severely limits steam injectivity below fracture pressure, necessitating the development of a Cold Lake specific cyclic steam stimulation (CSS) process throughout the 1980s. Continual process optimization combined with infill drilling has resulted in a progressive increase in expected bitumen recovery from 13% to greater than 40% of effective bitumen in place (EBIP). A multi-disciplinary reservoir management effort conducted over the last several years has provided the view that Cold Lake recovery levels may potentially be increased to over 65% by adapting steamflood principles to mature CSS areas of the reservoir: reservoir simulation was used to define the steamflood opportunity’s technical and economic viabilityan extensive selection process based on several criteria was used to select an appropriate field trial locationtrial plans were reviewed with experts with California steamflood experiencea Cold Lake steamflood field trail was designed, implemented and successfully operated for three years As cyclic process efficiency declines due to lack of steam confinement, steamflood technologies become an attractive recovery scheme in mature Cold Lake reservoir by capitalizing on large scale inter-well communication while focusing on gravity drainage: trial results to date are encouraging and in agreement with performance predictionssuccess to date has benefited from the evaluation of prior trails at Cold Lake, review of global steamflood analogs and extensive reservoir simulation efforts prior to field trial design and implementationsteam confinement is a significant but manageable operational challenge