Factbox: Chevron returns workers to U.S. Gulf platforms as storm eases

HOUSTON (Reuters) - Chevron Corp (CVX.N) was sending workers back out to oil platforms in the U.S. Gulf of Mexico on Saturday, a sign the worst of Tropical Storm Karen has passed deepwater areas of the basin.

The storm has so far shut down about half of all oil output in the U.S. Gulf, according to the government, and a refinery in Louisiana has reduced rates because its supply of crude was affected. Chevron said its production was minimally impacted by the storm.

A Friday report from the U.S. Bureau of Safety and Environmental Enforcement said 49.5 percent of crude oil output was down, along with about 39 percent of natural gas output.

The U.S. Gulf produces about 1.3 million barrels of oil a day (bpd), according to the U.S. Energy Information Agency.

The Gulf of Mexico accounts for about 19 percent of U.S. oil production and 6 percent of natural gas output. Energy companies have said they halted facilities with capacity of about 1.06 million barrels of oil a day, though many platforms normally do not run full bore.

About 30 percent of U.S. natural gas processing plant capacity and 40 percent of the country's refining capacity also line the Gulf Coast.

Motiva Enterprises LLC (MOTIV.UL) said on Friday it has begun to reduce rates at its 233,500 bpd Norco, Louisiana plant after the storm delayed shipments of oil.

The Norco plant is not in the path of the storm as defined by the U.S. Department of Energy (DoE), but its supplies were affected. The DoE said the cyclone was expected to pass over five Gulf Coast refineries with combined capacity of nearly 1 million bpd. Other nearby refineries could be affected if the storm's path changes.

The National Oceanic and Atmospheric Administration had forecasted above-normal activity for the 2013 Atlantic hurricane season, but cooler ocean waters were expected to make it harder for storms to form. In August NOAA said they expected 13 to 19 named storms, of which six to nine could become hurricanes.

The storm was weakening but could gain strength over the weekend.

OFFSHORE PRODUCTION IMPACT

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OIL/GAS Company Asset Capacity oil/gas Date Shut Restarted

Petrobras Cottonwood 20,000 boepd Oct 4 N/A BP Atlantis 200,000 bpd/180 mmcf/d Oct 4 N/A BP Thunder Horse 250,000 bpd/200 mmcf/d Oct 3 N/A BP Mad Dog 80,000 bpd/60 mmcf/d Oct 3 N/A BP Na Kika 130,000 bpd/550 mmcf/d Oct 3 N/A

Hess Baldpate 60,000 bpd/200 mmcf/d Oct 3 N/A

BHP Shenzi 120,000 bpd/50 mmcf/d Oct 3 N/A

Neptune 50,000 bpd/50 mmcf/d Oct 3 N/A

Anadarko Ind Hub 1 bcf/d Oct 3 N/A

Marco Polo 120,000 bpd.300 mmcf/d Oct 3 N/A

Constitution 70,000 bpd/200 mmcf/d Oct 3 N/A

Neptune 14,000 bpd/23 mmcf/d Oct 3 N/A

Exxon N/A 1,000 bpd gross liquids Oct 3 N/A

Williams Canyon Station 500 mmcf/d Oct 3 N/A

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REFINERIES NEAREST STORM

Company Location Capacity Status

(1,000 bpd)

Chalmette Chalmette 193 Monitoring

Chevron Pascagoula MS 330 CDU shut, monitoring Exxon Baton Rouge LA 502.5 Monitoring

Motiva Convent LA 235 Reducing rates Motiva Norco LA 233 Reducing rates

Valero Norco LA 205 Monitoring

Meraux LA 125 Monitoring

Phillips 66 Belle Chasse LA 247 Monitoring

Westlake LA 239.4 Monitoring Marathon Garyville LA 522 Monitoring

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PIPELINES, PORTS

* Destin Pipeline -- Declared force majeure because unable to provide natural gas services from offshore Gulf receipt points.

* The Louisiana Offshore Oil Port (LOOP) was suspending marine operations, the U.S. Department of Energy said.

* Enterprise Products Partners (EPD.N) evacuated four shallow-water junction platforms that receive oil and gas to deliver to onshore facilities. Those include West Delta 68, which connects natural gas output from Anadarko's Independence Hub with Kinder Morgan's (KMI.N) Tennessee Gas Pipeline.

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PREPARATION, EVACUATIONS

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* Petrobras (PETR4.SA) -- Shut in production and evacuated its Cottonwood field in the Gulf.

* BP (LSE:BP.) -- Shutting in production at all company-operated deepwater facilities and evacuating workers.

* Hess Corp (HES.N) -- Shut in production and evacuating a platform.

* Anadarko Petroleum Corp (APC.N) -- Shut in production and fully evacuating four platforms.

* Exxon Mobil Corp (XOM) -- Shutting in 1,000 bpd gross liquids production, evacuating non-essential workers.

* BHP Billiton (BHP.AX) -- Shut in production and fully evacuating at both Gulf platforms.

* Williams Cos -- Shut production at 500 mmcf/d shallow-water Canyon Station platform, workers at Chevron Corp's (CVX.N) Blind Faith and ENI's (ENI.MI) Devil's Tower platforms reduced to core crews after noon-essentials evacuated.

* Royal Dutch Shell (RDSa.L) -- Evacuating non-essential workers at Eastern and Central Gulf facilities, no production impact.

* Chevron Corp (CVX.N) -- Evacuating some workers, production unaffected.

* BP Plc (LSE:BP.) -- Evacuating non-essential workers, no production impact.

* Murphy Oil Corp (MUR) -- Evacuating non-essential workers, no production impact.

* Marathon Oil Corp (MRO) -- Evacuating non-essential workers from its operated Ewing Bank platform, no production impact.

* ConocoPhillips (COP.N) -- Expects no impact as single operated platform far west of storm's path, no evacuations.

* Petrobras (PETR4.SA) -- Monitoring storm, taking all necessary precautions.

(Reporting by Kristen Hays, Terry Wade and Erwin Seba)