The Oklahoma-based company recorded earnings before interest, taxes, depreciation and amortisations of $708 million compared to $422 million last year.
Revenue was 10% higher than the 2012 second quarter, at $1.1 billion.
While net profit declined 20% to $323 million, adjusted net profit (after items typically excluded from published analyst estimates were removed) was double last year at $246 million.
The company also recorded a 43% increase in production, totalling 135,700 barrels per day of oil equivalent.
