Management believes that the non-GAAP measure of operating cash flow is useful as an indicator of an oil and gas exploration and production company 's ability to internally fund exploration and development activities and to serviceor incur additional debt . The company has also included this information because changes in operating assets and liabilities relate to the timing of cash receipts and disbursements which the company may not control and may not relate to the period in which the operating activities occurred.Operating cash flow should not be considered in isolation or as asubstitute for net cash provided by operating activities prepared in accordance with GAAP .