After weeks of debate, the Senate Energy Committee decided yesterday to let the entire Senate grapple with the complex problem of rewriting natural gas law.

By an 11-to-9 vote, a controversial bill that would remove all controls from natural gas was sent to the full Senate "without recommendation."

The vote became possible when two senators, Mark O. Hatfield (R-Ore.) and Lowell P. Weicker Jr. (R-Conn.), agreed to report the bill out without a recommendation of approval, according to committee Chairman James A. McClure (R-Idaho).

Three Democrats joined with eight Republicans in voting for the action

Though the bill has less protection for consumers and would retain price controls longer than the Reagan administration version, Energy Secretary Donald P. Hodel termed it "a step in the right direction" and expressed hope for Senate passage early in September.

But McClure, who yesterday noted that the committee had spent a "nearly unprecedented" 31 working days marking up the bill, seemed more relieved than encouraged by his panel's action.

"As long and as tough as this step has been, the next one's tougher," he said. "And assuming we get a bill passed on the floor, I think agreement between the Senate and House is even tougher."

A House Energy subcommittee is bogged down over what to do about "old gas"--gas discovered before 1977 which costs relatively little to produce, and which under current law will remain indefinitely under price controls.

The Senate bill would end all price controls on gas three years after the measure is enacted, a move opponents charge would produce a $40 billion windfall for the major oil companies that control most old gas.

Just before final action yesterday the Senate panel voted 11 to 8 to retain the provision that would lift controls from old gas. But Sen. Howard M. Metzenbaum (D-Ohio) has promised to filibuster against it if necessary.

McClure said that while he expected the legislation to reach the floor sometime in the fall he had not obtained "any specific commitments" from Senate Majority Leader Howard H. Baker Jr. (R-Tenn.).

The bill reported out yesterday would phase out controls on old gas by raising its price to "market level" over three years. The legislation also would try to bring the price of the highest-cost gas down to market level during the first year.

It also attempts to deal with so-called "take-or-pay" contracts, which force utilities to take large amounts of high-priced gas or pay for it anyway. The bill provides that, during the transition to decontrol, utilities would have to take only 50 percent of the gas they have contracted for during the first year, 60 percent during the second year and 70 percent during the final year.

But the Senate panel, on a voice vote, rejected an attempt to give utilities a similar escape clause from contracts calling for them to purchase high-priced imported gas. The panel agreed to deal with this problem separately.

While the Natural Gas Supply Association, which represents gas producers, said it was "pleased" by the committee's action in reporting the bill, the American Gas Association, which primarily represents utilities, said the bill "contains provisions that will unnecessarily increase gas prices."

The Citizen-Labor Energy Coalition, which has sponsored a rival approach to reducing natural gas prices, expressed hope that the full Senate "will be far more responsive to the needs of gas consumers for price relief as opposed to the greed of producers for increased profits."