UPDATE 1-TGS-Nopec Q1 falls, sees pick up in demand

* Q1 EBIT down 57 percent to $20 million, beats forecast

* Says core library data sales "lumpy", visibility low

* Maintains 2009 net revenue target of $470-530 million

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OSLO, May 7 (Reuters) - Norwegian seismic surveyor TGS-Nopec Geophysical (TGS.OL) said on Thursday sales activity had clearly risen in recent weeks and kept its 2009 targets after posting a smaller-than-forecast drop in first quarter earnings.

TGS-Nopec, which supplies seismic surveys to the oil and gas industry, reported a January-March operating profit of $20 million, down from $47 million a year ago and above an $18 million average forecast from a Reuters poll of analysts.

The company maintained guidance for 2009 net revenues of $470-$530 million after reporting a 33 percent drop in first-quarter net revenues to $71 million.

"We are clearly seeing increased sales activity in recent weeks and we continue to remain optimistic about the longer term fundamentals for our sector," chief executive Hank Hamilton said in a statement. "We are well positioned to take advantage of opportunities that these difficult cycles usually present."

TGS-Nopec said it has begun to implement a plan to reduce operating expenses beginning in the second quarter.

TGS-Nopec said it has historically earned 70-80 percent of revenues from sales of library data to various oil and gas producers, instead of scans carried out for a specific client.

"These sales are lumpy in nature, have very low visibility and are difficult to accurately forecast," TGS-Nopec said.

The company said that from the start of 2009 sale opportunities were "steadily increasing" and expected a positive near term impact from Norway's 20th oil and gas licensing round, announced last week. [ID:nL4632168]

TGS-Nopec repeated its 2009 targets of multi-client library investments of $230-270 million and average pre-funding in the range of 45-55 percent of investments.

It sees the average annualized multi-client amortisation rate in the range of 35-40 percent of net revenues and proprietary contract revenues in the range of 5-10 percent of total net revenues.

Shares in TGS-Nopec closed at 53.30 crowns on Wednesday, up 25 percent over the past three months but still 37 percent down on a year ago. (Reporting by Oslo newsroom; Editing by Dan Lalor)