* Iran attacks disrupt Qatar's LNG output, impacting

global energy markets

* Cheniere and Venture Global ( VG ) shares surge amid supply

concerns

* Analysts warn of prolonged outages affecting LNG prices

and demand

By Curtis Williams and Scott DiSavino

HOUSTON, March 19 (Reuters) - Shares of U.S. liquefied

natural gas producer Cheniere Energy jumped to an

all-time high while Venture Global ( VG ) initially spiked as

much as 13% on Thursday after QatarEnergy said attacks by Iran

may shut nearly a fifth of its LNG output for up to five years.

Cheniere hit a record high in intraday trade and its shares were

up about 7% to $285 in afternoon trading, while Venture Global ( VG )

reversed most of the gains earlier in the day. Venture Global ( VG )

shares are up about 50% over the past month.

The Thursday rally followed comments from QatarEnergy CEO Saad

al-Kaabi, who told Reuters that Iranian strikes had knocked out

17% of the Gulf nation's LNG export capacity.

Al-Kaabi said two of Qatar's 14 LNG trains and one of its two

gas-to-liquids plants were damaged. Repairs will sideline 12.8

million metric tons per year of LNG for three to five years, he

said. Qatar is the world's largest LNG exporter, followed by the

U.S.

Cheniere can export more than 51 million metric tons of LNG per

year, while Venture Global ( VG ) can ship out more than 37 million

tons, according to the companies' recent earnings calls.

GLOBAL ENERGY MARKETS DISRUPTED

The conflictthat broke out late last month has disrupted global

energy markets after the Strait of Hormuz was effectively shut

down, blocking around a fifth of global oil flows and forcing

QatarEnergy LNG to suspend shipments. Analysts had expected

short-term volatility but now warn repeated attacks on energy

infrastructure could trigger longer lasting shifts in LNG and

gas pricing.

Cheniere sells 94% of its output under long-term contract,

while Venture Global ( VG ) keeps about 30% for the spot market.

Since the U.S. and Israel started bombing Iran on February

28, U.S. gas prices have jumped about 12% compared to gains of

91% in Europe and 88% in Asia. Gas is trading at 37-month highs

near $21 per million British thermal units (mmBtu) at the Dutch

Title Transfer Facility (TTF) benchmark in Europe and near $20

at the Japan-Korea Marker (JKM) benchmark in Asia.

Before the latest strikes, consultancy Wood Mackenzie had

estimated Qatari LNG output could return to full capacity within

four to six weeks following a brief outage. That timeline will

now be extended depending on the severity of the damage, it said

in a note on Thursday.

"The damage to the two LNG trains at Ras Laffan will

inevitably mean that suppliers elsewhere around the world will

have more business for the coming few years. But the higher

European and Asian gas prices we have seen in recent weeks are

now likely to remain elevated for longer, which undoubtedly will

result in fuel-switching in both the power and industrial

sectors," said Wood Mackenzie Europe Gas & LNG director Tom

Marzec-Manser.

Ira Joseph, a fellow at Columbia University's Center on Global

Energy Policy, said that some of the lost Qatari supply could be

offset by new U.S. capacity expected to come online from Golden

Pass LNG owned by Exxon Mobil ( XOM ) and QatarEnergy in Texas,

in addition to three other plants under construction by Sempra ( SRE )

, NextDecade ( NEXT ) and Venture Global ( VG ).

Joseph said the key question moving forward is whether Qatar's

massive North Field expansion will also be affected.

"If it is impacted, then structurally we have to adjust our

LNG prices higher," he said. "But if we do that, we also have to

weaken our demand growth outlook."

Analysts at Jefferies warned that prolonged outages could lead

to sustained higher prices, although there will be some demand

destruction and coal-for-gas switching. Buyers, however, are

increasingly prioritizing supply diversity and geopolitical

resilience over the lowest-cost LNG, they added.