Allis-Chalmers Energy Inc., Houston, (Amex: ALY) plans to acquire substantially all the assets of Oil & Gas Rental Services Inc., Morgan City, La., for $291 million in cash and 3.2 million shares valued at approximately $15.97 each in a deal valued at $342.1 million. Oil& Gas Rental Services provides rental tools to offshore and onshore E&P companies, with an inventory including drill pipe, spiral heavy weight drill pipe, tubing work strings, blow-out preventers, choke manifolds and various valves and handling tools. The company has facilities in Morgan City and Victoria, Texas, and provides equipment worldwide, including internationally in Malaysia, Colombia, Russia, Mexico and Canada.