Noble Midstream's unitholders will get 0.1393 Chevron shares for each unit held under the new agreement, Chevron said.

As of Chevron's Thursday closing price, the offer translates to $14.55 per Noble Midstream share. The oil major's original offer, announced in February, envisioned Noble Midstream shareholders getting about $12.47 per share.

The final value under the new deal, however, will depend on the price Chevron's shares are trading at when the deal closes, expected in the second quarter.

Chevron's shares were up 2.4% at $107.39 in pre-market trading on Friday, boosting the deal value to about $14.96 per Noble Midstream share. The pipeline operator's units were down marginally at $15.

Chevron, the second-largest U.S. oil producer, in October closed a $4.1 billion all-stock purchase of smaller rival Noble Energy, gaining a nearly 63% stake in Noble Midstream alongside large shale and international natural gas reserves.