a hedging program to partially mitigate the price volatility. Our investment decisions are based on longer-term commodity prices based on the long-term nature of our projects and development plans. Also, BP has agreed to partially carry our exploration, appraisal and development program in Mauritania and Senegal over the next several years. Current commodity prices, our hedging program, partner carries and our current liquidity position support our capital program for 2018. As such, our 2018 capital budget is based on our development plans for Ghana and our exploration and appraisal program. Our future financial condition and liquidity can be impacted by, among other factors, the success of our exploration and appraisal drilling program, the number of commercially viable oil and natural gas discoveries made and the quantities of oil and natural gas discovered, the speed with which we can bring such discoveries to production, the reliability of our oil and gas production facilities, our ability to continuously export oil and gas, our ability to secure and maintain partners and their alignment with respect to capital plans, the actual cost of exploration, appraisal and development of our oil and natural gas assets, and coverage of any claims under our insurance policies. As part of the Facility amendment and restatement process, the lenders approved a redetermination, setting the borrowing base under our Facility at $1.5 billion (effective February 22, 2018). The borrowing base calculation includes value related to the Jubilee, TEN, Ceiba and Okume fields. Sources and Uses of Cash The following table presents the sources and uses of our cash and cash equivalents for the years ended December 31, 2017, 2016 and 2015: Years Ended December 31, 2017 2016 2015 (In thousands) Sources of cash, cash equivalents and restricted cash: Net cash provided by operating activities . . . . . . . . . . . . . . . . . . $236,617 $ 52,077 $ 440,779 Net proceeds from issuance of senior secured notes . . . . . . . . . . — — 206,774 Borrowings under long-term debt . . . . . . . . . . . . . . . . . . . . . . . . 200,000 450,000 100,000 Proceeds on sale of assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222,068 210 28,692 658,685 502,287 776,245 Uses of cash, cash equivalents and restricted cash: Oil and gas assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140,495 535,975 823,642 Other property . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2,858 1,998 1,483 Equity method investment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231,280 — — Payments on long-term debt . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250,000 — 200,000 Purchase of treasury stock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2,194 1,981 18,110 Deferred financing costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 — 9,030 626,894 539,954 1,052,265 Increase (decrease) in cash, cash equivalents and restricted cash . . . $ 31,791 $(37,667) $ (276,020) Net cash provided by operating activities. Net cash provided by operating activities in 2017 was $236.6 million compared with net cash provided by operating activities of $52.1 million in 2016 and $441 million in 2015, respectively. The increase in cash provided by operating activities in the year ended December 31, 2017 when compared to the same period in 2016 is primarily a result of an increase in oil and gas revenue combined with LOPI proceeds, net and a decrease in exploration expense related to the stacked rig costs and rig option cancellation payment as well as a decrease in 90