Oasis Petroleum Inc. (together with our consolidated subsidiaries, the "Company," "we," "us," or "our") was originally formed in 2007 and was incorporated pursuant to the laws of the State of Delaware in 2010. We are an independent exploration and production ("E&P") company focused on the acquisition and development of onshore, unconventional oil and natural gas resources in the United States. Oasis Petroleum North America LLC ("OPNA") and Oasis Petroleum Permian LLC ("OP Permian") conduct our exploration and production activities and own our proved and unproved oil and natural gas properties located in the North Dakota and Montana regions of the Williston Basin and the Texas region of the Delaware Basin, respectively. We operate a midstream services business through OMS Holdings LLC ("OMS"), through which we own a majority of the outstanding units of Oasis Midstream Partners LP (NYSE: OMP) ("OMP" or "Oasis Midstream"), which completed its initial public offering on September 25, 2017. We also operate a well services business through Oasis Well Services LLC ("OWS").
As of December 31, 2018, we have accumulated 413,552 net leasehold acres in the Williston Basin, of which approximately 97% is held by production. We are currently exploiting significant resource potential from the Bakken and Three Forks formations, which are present across a substantial portion of our acreage. We believe the location, size and concentration of our acreage create an opportunity for us to achieve cost, recovery and production efficiencies through the development of our project inventory. In addition, on February 14, 2018, we closed on an acquisition of approximately 22,000 net acres in the Delaware Basin, representing our initial entry into the Delaware Basin (the "Permian Basin Acquisition"). The Permian Basin Acquisition more than doubled our core net inventory and allows us to further capitalize on our operational strengths. As of December 31, 2018, we have accumulated 23,366 net leasehold acres in the Delaware Basin, of which approximately 67% is held by production. Our management team has a proven track record in identifying, acquiring and executing large, repeatable development drilling programs, which we refer to as "resource conversion" opportunities, and has substantial Williston Basin and Delaware Basin experience.
In 2018, we completed and placed on production 121 gross operated wells and had average daily production of 82,525 barrels of oil equivalent per day ("Boepd") in the Williston and Delaware Basins. As of December 31, 2018, we had 1,053 gross (784.6 net) operated producing horizontal wells in the Bakken and Three Forks formations in the Williston Basin and 31 gross (29.5 net) operated producing horizontal wells in the Delaware Basin. As of December 31, 2018, DeGolyer and MacNaughton, our independent reserve engineers, estimated our net proved reserves to be 280.1 million barrels of oil equivalent ("MMBoe") in the Williston Basin, of which 67% were classified as proved developed and 70% were oil, and net proved reserves to be 40.5 MMBoe in the Delaware Basin, of which 30% were classified as proved developed and 80% were oil.