* Weak Canadian oil prices cut into producer profits * Lack of pipeline space lowers prices * Heavy oil producers take biggest hit * Refiners benefit from low oil price By Scott Haggett CALGARY, Alberta, Jan 13 - Canada's independent oil producers may face months of depressed earnings and weak share prices as they jockey for space on the country's over-full oil pipelines. The independents, companies that focus on producing oil and gas and have no refining or marketing o