8. Oil and Gas Properties

A summary of oil and gas properties follows:

	September 30, 2016 (unaudited)			December 31, 2015
	(In thousands)
Proved properties and equipment	$	525,809		$	584,692
Proved properties and equipment held for sale		79,537			—
Unproved properties		71,658			70,298
Less accumulated depreciation, depletion, and amortization		(160,793	)		(166,890	)
Less accumulated depreciation, depletion, amortization, and impairment on properties held for sale		(65,922	)		—
	$	450,289		$	488,100

On September 26, 2016, Amadeus Petroleum, Inc. and T-N-T Engineering, Inc. entered into a purchase and sale agreement with AVAD Energy Partners, LLC and Vendera Resources II, LLC to sell their remaining interest in producing wells and related oil and gas leases in its conventional properties located in multiple counties in Texas, effective as of July 1, 2016. Aggregate production related to the properties was 436 Boe/d during the third quarter of 2016. The sale price approximated $14,000,000. The transaction closed on October 31, 2016. As of September 30, 2016, the Company reported an impairment charge of approximately $29.1 million, representing the carrying value in excess of fair value, less the cost to sell the properties. Asset retirement costs of $4 million and the related asset retirement liability of $4.5 million have been included in the carrying value of the properties as well as the impairment charge calculation. The table above provides separate amounts for the carrying value of the assets held for sale and the related accumulated depletion and impairment allowances.

During 2016, certain leased acreage was set to expire in Montana as part of the Bakken, Three Forks, and Lower Lodgepole formations (the “Poplar Properties”). Based on our decision to defer drilling on the Poplar Properties during the three months ended June 30, 2016, we recorded an approximate $1.9 million impairment charge related to leased acreage expiring during 2016. This was calculated through the allocation of our current carrying value of the properties across our proportionate share of the acreage.

If pricing continues to decline, it is reasonably likely that the Company may have to record impairment of its oil and gas properties subsequent to September 30, 2016.