A.R. "Tony" Sanchez, originally from Laredo, Texas, became a successful lawyer, independent oilman, and entrepreneur. In 1972, he and his father formed the South Texas Exploration Company, changing the name to Sanchez-O’Brien when Brian O’Brien joined the Company in 1973. Together they discovered the Bob West Field located in Zapata and Starr counties in Texas, producing from Wilcox sands. They also found the large Lobo Wilcox Field in Webb County, Texas, north of the Rio Grande River. Later, Sanchez and O’Brien went their separate ways professionally, and Tony established Sanchez Oil and Gas, a family-owned company. He and his sons went on to establish two public companies, Sanchez Energy and Sanchez Production Partners. Both companies are active drilling wells in the Eagle Ford shale plays in Dimmit, Maverick, Gonzales and Fayette counties in Texas and in the Deep Tuscaloosa Marine shale play in Louisiana and Mississippi.