The technician, who spoke on condition of anonymity because he was not authorized to comment on the work, said that engineers had discussed stopping work on the relief well in favor of a “bullhead kill.” In that operation, heavy mud would be pumped in through existing pipes and the oil and gas would be forced back into the oil reservoir at the bottom of the well.

The procedure is somewhat similar to the “top kill” method that failed in early June, but would be much more likely to succeed because with the well sealed, no oil or gas would be moving inside.

A BP spokesman said Saturday that the relief well was still considered the ultimate solution to the leak.

With the relief well strategy, the blown-out well would have to be reopened when the mud pumping began. The well would not have to be reopened to try a bullhead kill, the technician said.

If the well is not reopened, the exact flow rate of oil may never be known. It is estimated at 35,000 to 60,000 barrels a day.

Mr. Wells said that if the well were reopened for containment, two vessels that had been collecting oil were on standby and a third with a device to funnel oil from the top of the cap could be brought in quickly.

But in reopening the well, engineers would have to let oil gush into the water, at least for a short time.

Mr. Wells said scientists were “not at all surprised” that pressure readings from the test were lower than had been expected if the well were, in fact, intact. But rather than the cause being damage to the well, he said, it could be that the reservoir of oil had been depleted by the gusher.