Antero Resources increased its proved reserves 4% in 2015, including 2.9 Tcfe through the drill bit and 1.1 Tcfe of ethane reserves added after its first de-ethanizer was placed online last month at the MarkWest Sherwood facility in Doddridge County, WV, the company said Wednesday.

Antero’s year-end proved reserves totaled 13.2 Tcfe, with a mix of 72% natural gas, 27% natural gas liquids (NGL) and 1% oil. The Marcellus Shale accounted for 86% of total proved reserves, with 14% from the Utica.

The Denver-based exploration and production (E&P) company, which operates primarily in the Marcellus and Utica, certainly saw the impact of low prices on its reserves portfolio in 2015. For its proved reserves, the pre-tax present value discounted at 10% (PV-10), based on Securities and Exchange Commission (SEC) pricing, was $3.6 billion as of Dec. 31, a 68% year/year decline. Including hedges, PV-10 based on SEC pricing was $6.7 billion, down 42% year/year. Assuming strip pricing, the outlook was better, with 2015 year-end proved reserves PV-10 of $5.7 billion before hedging and $8.2 billion including Antero’s hedges.

For these calculations, Antero assumed Appalachian-weighted average SEC pricing of $2.56/MMBtu, $50.13/bbl for oil and $23.09/bbl for NGLs. It assumed strip pricing of $3.23/MMBtu, $53.66/bbl and $26.12/bbl respectively.

The company said low prices led it to reclassify 2.3 Tcfe of proved undeveloped reserves it no longer plans to develop over the next five years. The E&P said these reserves represent mostly dry-gas areas on the eastern portion of its Marcellus acreage, which carry “a higher operating cost structure and do not receive liquids-related pricing.”

Antero removed 4.6 Tcfe of probable and possible reserves in the Upper Devonian Shale due to low prices, driving a 9% year/year decrease in year-end proved, possible and probable reserves. It finished the year with total proved, probable and possible reserves of 37.1 Tcfe.

Antero said roughly 30% of its 569,000 net acres were classified as proved as of Dec. 31, with the company adding that it expects “a substantial portion of its Marcellus and Utica shale acreage will be added to proved reserves over time as more wells are drilled.”

The E&P estimated it spent $1.85 billion on capital costs in 2015, with preliminary all-in finding and development costs for its proved reserve additions averaging 80 cents/Mcfe including performance and price revisions.