* Regulator imposes steam restrictions after spills
* Four spills of water-bitumen mix this year
* Restrictions will not change production targets
CALGARY, Alberta, July 18 Steam restrictions imposed on the Wolf Lake and Primrose oil sands projects after spills of bitumen emulsion at the northern Alberta sites should not change the 2013 production forecast, Canadian Natural Resources Ltd said on Thursday.
The Alberta Energy Regulator imposed the restrictions on the two projects, which together produce about 100,000 barrels of tar-like bitumen per day, after four spills of bitumen emulsion at the sites this year.
The company said in a statement it is cleaning up the spills -- the latest was on June 24 -- made up of water mixed with bitumen and they do not pose a health risk.
"We are investigating the likely cause of the occurrence, which we believe to be mechanical," Canadian Natural said in a statement. "(We are) working with the AER to minimize the risk of any future occurrences, we have made adjustments to our current steaming strategy and monitoring programs."
The regulator ordered the company to accelerate its clean-up effort at the spill sites and restrict the amount of steam being pumped into the oil sands reservoir.
The two projects use the high-pressure cyclic steam stimulation method to produce bitumen. Steam is pumped into a well for an extended period to liquefy the reserve. The bitumen is then pumped out using the same well.
Canadian Natural shares rose 55 Canadian cents to C$33.92 on the Toronto Stock Exchange on Thursday.