UPDATE 4-Halliburton says tough to grow revenue 20 pct in '09

* Will struggle to hit revenue growth target of 20 pct

* Profit margin expansion in int'l markets seen limited

* CEO sees no need to change capital spending plans now

* Shares end down 8 percent (Adds CEO quotes on capital spending, exploration, closing stock price)

By Anna Driver

HOUSTON, Nov 19 (Reuters) - Halliburton Co (HAL.N) will struggle in 2009 to meet its long-term goal of increasing revenue by 20 percent a year, due to commodity price volatility and the global financial crisis, the company's chief financial officer said on Wednesday.

Turmoil in world financial markets and a sharp selloff in crude oil and natural gas have prompted energy companies, both large and small, to postpone expensive projects or slow spending on drilling in order to conserve cash.

Shares of Halliburton and others like its larger rival Schlumberger Ltd (SLB.N) have been hammered by worries about steep cuts to exploration spending, the lifeblood of oilfield services firms.

The problem is especially acute in North America, where smaller oil and gas companies have slashed budgets and idled many drilling rigs. On Tuesday, Barclay's capital forecast exploration spending in the U.S. and Canada would fall 25 percent next year before rebounding in 2010.

So it will be "very challenging" for Halliburton to meet its revenue growth target and other financial targets in 2009, CFO Mark McCollum told investors at an analyst meeting, in remarks broadcast over the Internet.

In recent years, Halliburton has grown its revenue 20 percent or better on an annual basis.

Shares of Halliburton ended down about 8 percent, or $1.48, to $16.18 on the New York Stock Exchange. The Philadelphia Stock Exchange index of oilfield service companies .OSX was off 6.6 percent.

Halliburton also will stop repurchasing its shares until it has a better sense that access to capital markets is improving, McCollum said.

"Right now, it's prudent to operate as if cash is king," he said.

Halliburton's priority is reinvesting in the business and keeping its merger and acquisition pipeline full, he said.

For now, the oilfield service company feels situated well enough to weather any downturn and plans to stick to its 5-year capital plan. Halliburton has hired about 14,000 employees so far in 2008, in line with prior years.

But both areas would be first in line for cuts if markets worsen, Dave Lesar, Halliburton's CEO told Reuters in an interview after the meeting.

"Flexibility is the linchpin of our strategy right now," Lesar said.

In 2008, Halliburton expects to spend about $2 billion on capital projects. The company spent $1.58 billion in 2007 and $834 million in 2006.

In North America, Halliburton said it is well positioned to weather a drop in the number of rigs, citing its expertise and reach in shale gas plays.

In its international markets, Halliburton expects capital constraints on new projects, and growth in its profit margins is expected to be limited in 2009.

Halliburton also is confident it can increase its market share internationally in 2009, but cautioned that a stronger U.S. dollar will hit revenue growth.

In the last six weeks, the rising U.S. dollar has become "an absolute headwind," Lesar told Reuters, adding that when adjusted for currency fluctuations, international sales should rise.

The company also expects that some speculative exploration projects will be pushed out a year or two, while customers that remain are expected to stay committed to those that have already been started, the CEO said. (Reporting by Anna Driver in Houston, with additional reporting by Braden Reddall in San Francisco; editing by Gerald E. McCormick and John Wallace)