SEOUL, Jan 28 : SK Innovation Co Ltd, owner of South Korea's top refiner SK Energy, on Wednesday posted an operating profit of 337 billion won ($235 million) for the October-December period, according to Reuters calculations. That compared with a profit of 160 billion won a year earlier and a 351 billion won forecast by LSEG SmartEstimate. Analysts estimated that solid refining margins and a weaker won had supported its quarterly results, but noted that operating losses at its battery unit, SK