A sale of Westbrick would mark an exit from the Canadian oil and gas production business for KKR.
KKR has owned Westbrick for a decade, longer than most of its investments, making a sale logical, one of the sources said.
KKR invested C$250 million in Westbrick when it was a smaller producer in 2012.
Apart from Westbrick, KKR's other investments in Canada include gas processing assets and a stake in the Coastal GasLink pipeline under construction.
"Anyone who knows me knows that Westbrick has been for sale every day since our existence," he told Reuters via email.