UPDATE 1-TGS-Nopec Q2 profits drop, project delays weigh

(Adds details, quotes; updates share price)

OSLO, Aug 9 (Reuters) - Norwegian seismic surveyor TGS-Nopec (TGS.OL) posted on Thursday a drop in profits for the second quarter, missing market expectations for a rise, hit by project delays and a less favourable mix of sales.

Pretax earnings at the supplier of seismic data to the oil and gas industry fell to $37 million in April-June from $45 million in the same quarter last year.

The result, which followed a mid-July revenue warning, undershot all forecasts from $42 million to $56 million in a Reuters survey of eight analysts whose average expectation was a rise to $48 million.

TGS-Nopec shares lost 2.4 percent at 110.25 crowns by 0757 GMT, underperforming a 0.8 percent drop in the Oslo bourse benchmark index .OSEBX and valuing the company at about $2.03 billion.

"This quarter's results were negatively impacted by project delays stemming from late 3D vessel deliveries, the absence of any high impact late sales and a less favourable mix of sales than in previous quarters," TGS-Nopec Chairman Claus Kampmann said in a statement.

Late sales are sales from the data library as opposed to sales of newly acquired seismic surveys.

But with the vessels now in full operation and sales opportunities ahead, Kampmann said, "our outlook is very positive."

In mid-July the company warned of project delays and cut its 2007 net revenue growth target to 15 to 20 percent from an earlier 20 to 25 percent.

TGS reiterated its full-year revenue growth target and repeated a forecast for 2007 investments in its multi-client data library of $160 million to $170 million, but raised its forecast for the level of prefunding to 60-70 percent from an earlier 50-60 percent.

Prefunding is money received up front from clients for projects. The multi-client library is a store of data which the company sells to various clients as opposed to exclusively contracted surveys.

At the end of July, TGS announced it would acquire rival Wavefield Inseis WAVE.OL in a $1.16 billion all-share deal to create a stronger new player to be called TGS Wavefield in the oilfield services sector.

"The merger process is proceeding as planned," Chief Executive Hank Hamilton said in the statement.

High oil and gas prices have spurred exploration around the globe, lifting the oilfield services industry broadly, including suppliers of seismic surveys like TGS-Nopec.

TGS's report followed strong quarterly earnings from bigger rivals Petroleum Geo-Services (PGS) (PGS.OL) of Norway, French-U.S. market leader CGGVeritas (GEPH.PA) and U.S. oilfield services group Schlumberger (SLB.N) whose WesternGeco seismic unit is also a competitor.