Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018		Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 38,560		$ 58
Accrued production receivable	125,788		146,334
Trade and other receivables, net	26,970		45,193
Derivative assets	93,080		0
Other current assets	11,896		10,670
Total current assets	296,294		202,255
Oil and natural gas properties (using full cost accounting)
Proved properties	11,072,209		10,775,792
Unevaluated properties	996,700		951,397
CO2 properties	1,196,795		1,191,058
Pipelines and plants	2,302,817		2,286,047
Other property and equipment	250,279		339,218
Less accumulated depletion, depreciation, amortization and impairment	(11,500,190)		(11,376,646)
Net property and equipment	4,318,610		4,166,866
Derivative assets	4,195		0
Other assets	104,123		102,178
Total assets	4,723,222		4,471,299
Current liabilities
Accounts payable and accrued liabilities	198,380		177,220
Oil and gas production payable	61,288		76,588
Derivative liabilities	0		99,061
Current maturities of long-term debt (including future interest payable of $85,303 and $75,347, respectively – see Note 6)	105,125	[1]	105,188
Total current liabilities	364,793		458,057
Long-term liabilities
Long-term debt, net of current portion (including future interest payable of $164,914 and $241,472, respectively – see Note 6)	2,664,211		2,979,086
Asset retirement obligations	174,470		165,756
Deferred tax liabilities, net	309,758		198,099
Other liabilities	68,213		22,136
Total long-term liabilities	3,216,652		3,365,077
Commitments and contingencies (Note 12)
Stockholders' equity
Preferred stock, $.001 par value, 25,000,000 shares authorized, none issued and outstanding	0		0
Common stock, $.001 par value, 600,000,000 shares authorized; 462,355,725 and 402,549,346 shares issued, respectively	462		403
Paid-in capital in excess of par	2,685,211		2,507,828
Accumulated deficit	(1,533,112)		(1,855,810)
Treasury stock, at cost, 1,941,749 and 457,041 shares, respectively	(10,784)		(4,256)
Total stockholders' equity	1,141,777		648,165
Total liabilities and stockholders' equity	$ 4,723,222		$ 4,471,299

[1] Future interest payable represents most of the interest due over the term of our 9% Senior Secured Second Lien Notes due 2021 (the “2021 Senior Secured Notes”), 9¼% Senior Secured Second Lien Notes due 2022 (the “2022 Senior Secured Notes”) and to a small extent our previously outstanding 3½% Convertible Senior Notes due 2024 (the “2024 Convertible Senior Notes”) and has been accounted for as debt in accordance with FASC 470-60, Troubled Debt Restructuring by Debtors. Our current maturities of long-term debt as of December 31, 2018 include $85.3 million of future interest payable related to the 2021 Senior Secured Notes and 2022 Senior Secured Notes that is due within the next twelve months. See January 2018 Senior Subordinated Note Exchanges and 2017 Senior Subordinated Note Exchanges below for further discussion.