UPDATE 1-Halliburton to help develop Iraq oilfield

* Letter of intent for development of Majnoon field

* Shell is lead operator with 45-percent share

* Plan to up production from 45,000 bopd to 1.8 million

NEW YORK, Aug 18 (Reuters) - Halliburton HAL.N said on Wednesday it has a been awarded a letter of intent to work with a Shell-led RDSa.L consortium developing the Majnoon field in southern Iraq, one of the world's largest oilfields.

Under terms of the letter, Halliburton will serve as project manager for the development work, in affiliation with rig contractor Nabors NBR.N and Iraq Drilling Company (IDC).

The contract is still subject to final approval by Iraqi authorities, the Houston-based company said.

Shell is lead operator and holds a 45-percent share, partner Petroliam Nasional Berhad (Malaysia’s state-owned Petronas) holds 30 percent and the Iraqi state holds 25 percent of the participating interests in all licenses.

Shell says the consortium intends to increase production from the current 45,000 barrels of oil per day to a targeted production plateau of 1.8 million barrels of oil per day.

Halliburton and its larger rival Schlumberger Ltd SLB.N have both been targeting Iraq, where oil companies have been eyeing new projects after winning contracts from Baghdad.

Halliburton’s former unit KBR was one of the U.S. government’s biggest contractors in Iraq after the U.S.-led invasion. (Reporting by Steve James; editing by Carol Bishopric)