(Adds background on drilling operation, Petronas stake)
HOUSTON, May 4 (Reuters) - Oil producer ConocoPhillips said all staff were safely evacuated from a drillship that listed and sank off the coast of Malaysia on Tuesday.
The Naga 7 drillship was being placed at a site off the coast of Sarawak state when one leg of the jack-up rig penetrated the soil, according to owner Velesto Energy Bhd . No drilling had begun.
A total of 101 employees were transferred to rescue vessels, according to Velesto, which said it had begun an investigation and was evaluating recovery options. Jack-up rigs are generally designed to work in shallow waters.
"All persons on-board have been safely evacuated off NAGA 7 with no known injuries," said ConocoPhillips spokesman John Roper.
The ship was to drill on a 300,000 acre (1.2 million hectares) block. Conoco is the operator and holds a 50% stake in the operation, while Malaysian state oil company Petronas holds an equal stake.
(Reporting by Gary McWilliams; Editing by Franklin Paul and Pravin Char)