• Coho Energy Inc., Dallas, and subsidiaries Coho Resources Inc. and Coho Oil & Gas Inc. have filed for Chapter 11 bankruptcy protection, since Coho received a notice of default from holders of its senior debt. Its plan to sell its Mississippi assets to an undisclosed third party last fall was cancelled. The properties-primarily in the Brookhaven, Laurel, Martinville and Soso fields-produced 5,205 BOE per day in second-quarter 2001. At Dec. 31 the assets contained approximately 30 million BOE of net proved reserves. Coho is looking for another buyer of the assets. • Bravo Natural Resources, Tulsa, plans to acquire the Midcontinent assets of Swift Energy Co., Houston, and certain partnerships. The purchase includes reserves of approximately 20 billion cu. ft. of gas, increasing Bravo's gas reserves approximately 30%, and 40 operated and 88 nonoperated Midcontinent wells primarily in Custer and Caddo counties, Okla. The properties produce 4.4 million cu. ft. of gas and 100 bbl. of oil per day, net. • Delta Petroleum Corp., Denver, plans to purchase the U.S. properties of Castle Energy Corp., Radnor, Pa., for cash and stock, for a deal value of $55 million. The assets include approximately 525 producing wells in 14 states, plus associated undeveloped acreage, with proved reserves of approximately 65 billion cu. ft. of gas equivalent, of which proved developed producing reserves are approximately 32 billion cu. ft. of gas equivalent. Additionally, Delta plans to purchase Piper Petroleum Co., Fort Worth, for stock in a deal valued at $6.31 million. Piper owns working and royalty interests in more than 300 oil and gas wells in Texas, Oklahoma and Louisiana, along with an interest in a coalbed-methane gas project in Australia. Separately, Delta purchased producing properties for cash and stock, for a deal value of $914,214, in six fields in the Edwards Reef trend in Lavaca, DeWitt, Karnee, Live Oak and McMullen counties, Texas. • Pioneer Natural Resources Co., Irving, Texas, has acquired 42 Parker & Parsley limited partnerships, adding net reserves of approximately 29 million BOE in the Spraberry Field, West Texas, and cash of approximately $12 million, for $99.2 million worth of Pioneer stock. • EnCap Investments LLC, Houston, R. Graham Whaling, Jim R. Smith and certain other members of the former senior management team of Michael Petroleum Corp. have formed a partnership, Laredo Energy, Houston, to acquire and develop gas reserves in south Texas. Also, Sawtooth Energy Partners LLC, Fort Worth, has been formed by Marty Searcy, president, with equity capital from EnCap. Matt K. Coughlin is vice president of acquisitions and technical services. Randol Rodgers is vice president of corporate development and planning. The three officers were previously with Union Pacific Resources. EnCap has also made an equity investment in North Richland Hills, Texas-based Ovation Energy LP, which has been formed by former Encore Acquisition Co. executives Kyle Schultz and Wes Welch, and Jeff Heyer, a former vice president at XTO Energy Inc. • Chaparral Resources Inc., Houston, may merge with U.K.-based Burren Energy Plc. The companies are evaluating assets and values. • Herbaly Petroleum Corp., Denver, has been purchased by Burlington Resources Inc., Houston. Herbaly's assets consisted of operated and nonoperated properties in southwest Wyoming. • Wyoming Oil & Minerals Inc., Colorado Springs, Colo., has acquired privately held New Frontier Energy Inc. for stock. New Frontier owns lease interests in Colorado, Wyoming, Montana and Kansas. • Hollimon Oil Co., San Antonio, and related parties have sold interests in five producing wells in Jones Creek, Wilcox Field, Wharton County, Texas, to Whiting Petroleum Corp., Denver, and Kaiser-Francis Oil Co., Tulsa. • NuWay Energy Inc., Irvine, Calif., plans to acquire Mendell Energy Technologies Inc., Denver, for stock. Mendell's major asset consists of approximately 95,000 acres of leases in Hill County, Mont. • Progress Ventures Inc., a wholly owned subsidiary of Progress Energy, Raleigh, N.C., plans to acquire approximately 215 gas-producing wells, 52 miles of intrastate pipeline and 170 miles of gas-gathering systems in Texas and Louisiana from Westchester Gas Co., Jonesville, Texas.