Offshore US Gulf output returning, ports remain shut

HOUSTON, July 24 (Reuters) - Offshore Gulf of Mexico oil and natural gas companies were restoring production on Thursday morning as Tropical Storm Dolly continued to close down shipping and affect refineries along the Texas coast.

Dolly, which weakened from hurricane strength on Wednesday night, was moving well inland, but high winds at the Gulf entrances to the Houston and Corpus Christi, Texas, ship channels meant those waterways to two coastal refining centers were closed to traffic.

Producers heaved sighs of relief that the storm packed none of the fury of hurricanes in 2005, which temporarily shut all Gulf of Mexico oil and gas production, pushing oil prices to then-record highs.

In the offshore, Mexican state-run oil monopoly Pemex said there was no impact on its production from Dolly, although it had evacuated 66 workers from an offshore platform used for repairs in the Arenque oil field.

U.S. producer Anadarko Petroleum Corp (APC.N) said it had fully restored by Thursday the equivalent of 30,000 barrels of oil production in the Gulf.

Producer Apache Corp APA.N said its offshore output had risen to 104 million cubic feet per day (mmcfd) as of Thursday morning from 115 mmcfd, but the same high winds hampering shipping were delaying helicopter flights to platforms.

Chevron Corp (CVX.N) said it began returning workers offshore on Wednesday and expected most to be back by Thursday. The company cut production by a minimal amount.

In Houston, where ship pilots stopped steering vessels to the busiest U.S. petrochemical port on Wednesday morning, 24 ships were waiting to enter the ship channel and 40 were waiting to leave on Thursday.

Valero Energy Corp (VLO.N) said on Wednesday its 130,000 barrel per day Houston refinery and 295,000 bpd refinery in Port Arthur would cut production between 10 percent and 20 percent because of the Houston channel closure.

In Corpus Christi, five ships were waiting to enter or exit the channel on Thursday morning, according the Aransas-Corpus Christi ship pilots. The three Corpus Christi refineries have not reported any problems due to the shipping halt.

The U.S. Gulf of Mexico can produce 1.3 million barrels per day of crude, or a quarter of domestic oil output, and 7.7 billion cubic feet per day of natural gas, or 13 percent of domestic gas output. (Reporting by Erwin Seba, Bruce Nichols in Houston; Richard Valdmanis, Janet McGurty in New York and Catherine Bremer in Mexico City; Editing by David Gregorio)