The document discusses a joint venture between Antero Midstream Partners LP and MPLX to invest in natural gas processing and fractionation infrastructure in the Marcellus and Utica Shales. The joint venture will construct up to 11 new processing plants and 3 fractionation facilities over the next four years at an estimated cost of $1.3 billion, with Antero Midstream's net investment of $650 million. The joint venture assets will be operated by MPLX and supported by long-term, fixed-fee agreements with Antero Resources and other producers.