July 17 (Reuters) - BlackRock ( BLK )-led investors in

Saudi Aramco's gas pipeline network Greensaif

Pipelines Bidco have tightened price guidance for dual-tranche

amortizing bonds and expect to raise $1.25 billion from each

tranche, IFR reported on Wednesday.

The price guidance for the 12-year bonds has been tightened

to 175/180 basis points over U.S. Treasuries (UST) and to

195/200 bps over UST for the 18-year portion, IFR said. The

tranches have weighted average lives of 10 and 14.5 years,

respectively.