CTX also operates a convenience store network in association with service station sites.
The company is 50% owned by American energy giant Chevron.
CTX shares slumped nearly 7% after forecasting a 1H profit drop as a high oil price and strong Australian dollar hurt margins and refinery outages disrupted fuel production.
The refiner is forecasting an up to 39% fall in 1H profit.
The company forecast a replacement cost of sales operating profit (a closely watched measure that excludes the value of its stockpiles) of $100 million to $115 million for the six months of 2011, down from $163 million last year.