By Nicole Jao

NEW YORK, Jan 22 (Reuters) - Top U.S. oil refiners are expected to post stronger fourth-quarter profits as product margins spurred by the ongoing Russia-Ukraine war boosted earnings, energy analysts said.

Fuel makers have reaped unexpected profits this year, after earnings slid from record levels in 2022, a year when a recovery in demand after the pandemic and Russia's invasion of Ukraine drove up fuel prices.

Diesel margins were driven largely by Ukrainian drone strikes on Russian refineries that impacted global supply, Tudor, Pickering, Holt & Co analyst Matthew Blair said in a note. Widening differentials for nearly every major crude grade against global benchmark Brent and falling crude prices also provided some respite for refiners, he said.

Valero VLO.N, the second-largest U.S. refiner by capacity, is set to kick off refiner earnings on Thursday, with analysts forecasting a profit of $3.27 per share, up from $0.64 per share profit a year ago, according to LSEG data.

Marathon Petroleum MPC.N, the top U.S. refiner by volume, is expected to report a per-share profit of $3.01, compared with a $0.77 per share profit a year ago, LSEG estimated.

Phillips 66 PSX.N is expected to report a profit of $2.19 per share, versus a loss of $0.15 per share a year ago, according to LSEG estimates.

VENEZUELAN CRUDE MAY BOOST GULF COAST REFINERS

The U.S. military’s ouster of Venezuelan President Nicolás Maduro earlier this month is set to reroute the country’s oil exports back toward the U.S., which would benefit complex refineries along the Gulf Coast refining and exporting hub.

The regime change in Venezuela, once a major oil producer, has prompted the market to believe crude differentials will widen out as more Venezuelan barrels make their way to the U.S., TD Cowen analyst Jason Gabelman said.

Gulf Coast refiners including Valero, Marathon and Phillips 66 own and operate complex refineries that were built to process heavy-grade crude - the type that Venezuela exports.

Investors will be seeking clarity from refining executives on Gulf Coast refineries' capacity to take Venezuelan crude, how fast they can take it, and how the increasing supply of the barrels will improve pricing, said Simon Wong, portfolio manager at Gabelli Funds.

"Venezuelan production remains structurally challenged and, in terms of ramping up its production, is really not solvable within a short timeframe," said Ben Hoff, head of commodity research at Societe Generale. "I think this is something we're going to ultimately see the economics play out."

(Reporting by Nicole Jao in New York; Editing by David Gregorio)

((Email: Nicole.Jao@thomsonreuters.com; Twitter/X: @ByNicoleJao; Phone: +1 646 540 2216))