The polymer flooding technology has been known and applied for a long time and yet there are very few cases of full field polymer floods around the world. This is even more so in heavy oil, which until recently was a domain strictly reserved to thermal recovery methods. This is no longer true following the success of a polymer flooding pilot in viscous oil in Canada.
The Pelican Lake field in Canada, a giant with 6.4 billion barrels of oil in place, contains a 12–14 API oil with a viscosity that varies between 800 and 80,000 cp at reservoir conditions. In spite of this high viscosity, a polymer flood pilot was undertaken under secondary conditions and proved very successful with the oil rate climbing from 43 bopd to over 700 bopd while the water-cut remains below 60%. Following the results of the pilot, the flood is now being extended to most of the field. With several hundreds of polymer injection wells in operation, this development is the second largest chemical flood in the world after Daqing (China) and the largest in heavy oil.
This paper will describe the history of the field, the implementation of the successful polymer flood pilot and then will focus on the specific challenges of the full field extension, including dealing with higher viscosity oil and various sources of water including produced water.
The Pelican Lake field* located approximately 250 km north of Edmonton, Alberta, Canada (Figure 1) was discovered in 1978 and started producing in 1980. It covers 177,000 ha, as part of the much larger Wabasca oil sand deposits. With 6.4 billion barrels Original Oil In Place OOIP and a primary recovery estimated at 5–10% OOIP, it presents a significant target for Enhanced Oil Recovery (EOR). But it is also a challenging reservoir with high viscosity oil in a thin formation.