California Resources Corp. has formed a joint venture with a San Diego energy company for development of the largest dry gas field in the state. The Chatsworth oil and natural gas company will allow Royale Energy Inc. to drill 30 wells at its Rio Vista field about 40 miles south of Sacramento. This deal will give Royale Energy access to the entire Rio Vista field to drill lower risk infill development wells, with significantly larger reserves. The Rio Vista field was discovered in 1936 and has produced approximately 4 trillion cubic feet of natural gas from more than 15 stacked gas formations. Shares of California Resources (CRC) closed down 83 cents, or more than 2 percent, to $34.27 on the New York Stock Exchange.