Aug 2 (Reuters) - Petrochemical manufacturer

LyondellBasell on Friday edged past Wall Street

estimates for second-quarter profit and said it expects margins

to continue to benefit from lower feedstock prices in the third

quarter.

U.S. prices of natural gas, a key feedstock for

chemical firms, have fallen 21.7% so far this year.

In the third quarter, the company said it expects margins to

benefit from low costs for natural gas and natural gas liquids

utilized in its North American and Middle East production,

relative to higher oil-based costs in most other regions.

"With the summer driving season underway, oxyfuels margins

are expected to remain above historical levels with high octane

premiums," it said in a statement.

Oxyfuels are a key component of clean-burning, high-octane

gasoline. They improve fuel efficiency, engine performance and

air quality by improving combustion efficiency, which in turn

reduces vehicle emissions, including greenhouse gases.

The company said its second-quarter volumes benefited from

increased production and improving seasonal demand.

LyondellBasell completed the sale of its U.S. Gulf

Coast-based ethylene oxide and derivatives business for $700

million in May, which benefited its second-quarter earnings by

58 cents per share.

It posted adjusted profit of $2.24 per share in the second

quarter, compared with analysts' average estimate of $2.23 per

share, according to LSEG data.