At least eight large oil companies will participate in Mexico's tender to partner with state oil company Pemex to develop the deep-water Trion field in the Gulf of Mexico, two sources from the National Hydrocarbons Commission (CNH) said. Mexican subsidiaries of BHP Billiton, BP, Chevron Corp., Inpex Corp., Total Exxon, Shell and Mitsubishi Corp. will bid on Dec. 5 to be part of the Joint Operating Agreement with Pemex, the sources, who spoke on c…