UPDATE 2-Vallourec sees worse ahead as Q1 sales fall

* Vallourec Q1 sales 1.313 bln euros, down 5.1 pct

* Vallourec says it sees further falls in sales, EBITDA

* Vallourec shares close down 3.8 pct before results

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By Helen Massy-Beresford

PARIS, May 13 (Reuters) - French seamless tube maker Vallourec (VLLP.PA: Quote, Profile, Research) pledged further cost cuts and said it expected sales and underlying profit to continue to slide after posting a 5.1 percent drop in sales in the first quarter.

Vallourec, which supplies the oil and gas, power, petrochemicals and auto sectors, in February had forecast a drop in sales of as much as 5 percent in the first quarter because of the global industrial slowdown.

"Vallourec anticipates a further reduction in sales and earnings before interest, tax, depreciation and amortisation (EBITDA) compared with the first quarter," it said in a statement on Wednesday.

Vallourec said it would reinforce cost-cutting measures taken in the first quarter to battle the slowdown. Vallourec is sticking to an estimate of capital expenditure of around 800 million euros this year, of which around half would be invested in Brazil, chief operating officer Jean-Pierre Michel said on a conference call.