An innovative if controversial bill could protect offshore waters in California from oil drilling by allowing oil companies to swap drilling claims in California for others in the Gulf of Mexico. The legislation, introduced yesterday by Sens. Barbara Boxer (D-Calif.), Dianne Feinstein (D-Calif.), Mary Landrieu (D-La.), and John Breaux (D-La.), would convert 40 offshore tracts into ecological preserves that would be forever protected from oil and gas drilling. That would be a welcome development for environmentalists, but some cast a skeptical eye at the bill anyway, calling it a bailout for big oil. The deal could be worth upwards of $2.8 billion to more than a dozen oil companies that have been frustrated in their attempts to develop oil leases off the coast of Southern California. The money would come in the form of credits usable for bidding on tracts in the central and western Gulf, as well as to offset royalty payments to the government.