UPDATE 1-Lower taxes lure big oil to Iraq oilfield deals

* Iraq to tax profit only, not all revenues

* Shell working with Exxon for West Qurna field

* Kirkuk, other 1st bid round fields not under renegotiation

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By Simon Webb

DUBAI, Oct 14 (Reuters) - Iraq has lured big oil firms into new service contracts on some of its giant oilfields by cutting taxes and sweetening terms to make the deals more profitable, industry sources said on Wednesday.

International oil companies are close to striking deals that would almost triple Iraq's output and catapult it up the table of global producers. The firms walked away from those deals at an auction just over three months ago.

Lower taxes were the main factor that convinced firms they could turn a profit where they previously saw too much risk on punishing terms, executives at international oil firms said.