(Corrects to add Reuters instrument code in first paragraph and remove incorrect RIC in 4th paragraph)
ASHGABAT, April 11 A unit of Germany's RWE AG will start drilling on the Turkmen part of the Caspian Sea shelf in the first quarter of 2013, a Turkmen government official said on Wednesday.
In 2009 RWE signed a deal to develop the so-called "Block 23" on Turkmenistan's Caspian shelf.
RWE is one of a few foreign companies working on the Turkmen Caspian shelf. Analysts say fields there are more risky and less lucrative than onshore deposits eyed by Western energy majors.
Turkmenistan says it will only hire foreign firms as contractors.
"RWE Dea AG has announced a number of international tenders - on providing services for hydrocarbon gas detection as well as for cable cabotage services - which are needed for drilling and exploration works near the twon of Ekerem," the official, who declined to be named, told Reuters.
"The start of the work is scheduled for the first quarter of 2013."
Turkmenistan holds a joint fourth place in the world with Saudi Arabia according to its natural gas reserves, BP data show.
The contract with the German company is important for the ex-Soviet state of 5.5 million which wants to diversify gas sales beyond Russia, China and Iran, because RWE is a shareholder of Nabucco, the planned gas pipeline which is set to bypass Russia and serve the European market. (Reporting by Marat Gurt; Writing by Dmitry Solovyov; Editing by William Hardy)