UPDATE 2-ADNOC issues four tenders for Shah gas project

* Contracts to be awarded in 2010

* ADNOC wants Shah project total costs to be about $10 bln

* ADNOC sees 30-50 pct decline in cost of all projects

(Adds analysts' quotes, background)

By Luke Pachymuthu and Raissa Kasolowsky

ABU DHABI, May 25 (Reuters) - Abu Dhabi National Oil Co (ADNOC) has issued tenders for four large contracts related to the Shah gas field development project, its chief executive said on Monday.

The contracts would be awarded in 2010, said an official at the state-run company, the United Arab Emirates' largest oil producer.

"Four huge tenders relevant to the development of the Shah gas field have been issued to contractors," ADNOC Chief Executive Yousef Omair bin Yousef told an industry conference.