During 2015, CONSOL Energy Inc. (CNX) added 934 billion cubic feet equivalent (Bcfe) of proved reserves through extensions and discoveries, the company said Feb. 5.

On Dec. 31, the 5.6 Tcfe of total proved reserves included 583 Bcfe, or 10.3%, oil, condensate and liquids. Marcellus Shale reserves accounted for 369 Bcfe, or 14.4%, of these heavier hydrocarbons.

In 2015, 329 Bcfe was produced and 284% of the production was replaced, the company said.

Drilling and completions costs totaled $618.3 million. The drillbit finding and development costs were lower than year-end 2014’s, CONSOL said.

Future development costs for proved undeveloped reserves (PUDs) are estimated to have been about $943 million. In 2015, PUDs made up 34% of total proved reserves, at 1,946 Bcfe. This was lower than year-end 2014’s makeup of 53%.

During 2015, proved developed reserves were 16% higher than 2014’s at 3,697 Bcfe. At year-end 2015, proved reserves in the Marcellus were 2,573 Bcfe, including 1,689 Bcfe of proved developed.

In the Marcellus, 81 gross wells with average lateral lengths of about 7,600 ft were turned in line. Their average EURs were about 2 Bcfe/1M ft of completed lateral, CONSOL said. The peak rates for 31 wells were greater than 10MMcf/d.

In the Utica, CONSOL and its joint venture partner turned in line 32 gross wells with an average completed lateral length of about 7,600 ft and EURs of up to 3 Bcfe/1M ft of completed lateral. In the dry Utica, four wells fully owned by CONSOL peaked at more than 20 MMcf/d per day.

Regarding finances, the reserve-based lending credit facility had a $2 billion borrowing base at year-end 2015.

CONSOL Energy Inc. is based in Canonsburg, Pa.