EnCana Corp. (ECA) and ConocoPhillips (COP) are seeking approval from environmental regulators in Canada for a 120,000-barrel-a-day expansion of their joint Christina Lake oil sands project in northern Alberta.

The two companies aim to boost the project's output limit to 218,000 barrels a day in three development phases, using steam to soften the tarry oil sands bitumen and pump it to the surface, according to documents filed with the province's environment ministry.

There were no details regarding the proposed schedule or budget for the expansion.

Christina Lake is the smaller of two oil sands developments forming part of the joint venture that EnCana and ConocoPhillips inked in 2006. The deal swapped equity in EnCana's oil sands assets for stakes in two of ConocoPhillips' refineries in Illinois and Texas.

Current production at Christina Lake is around 14,000 barrels a day and work has started to boost this by 40,000 barrels a day. The companies also plan to double output at the Foster Creek oil sands development this year to 120,000 barrels a day.

Both EnCana and ConocoPhillips have cut back their spending plans for 2009 after oil and natural gas prices plummeted from last summer's highs.

-By Hyun Young Lee, Dow Jones Newswires; 613-237-0669; hyunyoung.lee@dowjones.com