Warren Resources Inc. is an energy company engaged in the exploration, development and production of domestic onshore crude oil and gas reserves. The Company focuses on the exploration and development of its waterflood oil recovery properties in the Wilmington field within the Los Angeles Basin of California, and its coalbed methane (CBM), natural gas properties located in the Rocky Mountain region. During 2013, the Company owned natural gas and oil leasehold interests in approximately 123,943 gross (93,350 net) acres, approximately 80% of which are undeveloped. The Company’s undeveloped acreage is located in the Rocky Mountains. The Company has identified approximately 150 gross drilling locations in its Wilmington field units. Additionally, the Company has identified approximately 175 gross drilling locations on its acreage in the Rocky Mountains, on 80-acre well spacing. During 2013, the Company had interests in approximately 480 gross (322 net) producing wells.