Woodside will hold a 73.5% stake in each of the titles, while BHP will hold the remaining 26.5%.
Woodside earlier held a 75% stake in the W-1-R permit, while the W-62-R was held 50% each by BHP and Woodside.
Woodside has been looking to line up gas sales and sell down part of its stake in Scarborough to help fund the project, but talks had been slowed by travel curbs and weak gas prices following a coronavirus epidemic.
The two companies have also agreed to apply for production licences for both titles.
“The production licence applications are another key step to unlocking the full value of the Scarborough resource through the expansion of our existing Pluto LNG facility,” Woodside Chief Executive Peter Coleman said in a statement.
The oil and gas producer aims for a final investment decision in 2020 for the Scarborough development, and first cargo in 2024.
Woodside posted this month an underlying profit, excluding one-off charges, of $1.06 billion (820 million pounds) for 2019, down from $1.42 billion a year earlier.
(This story corrects to remove earlier stake holdings in second paragraph and adds third paragraph to specify previous stake holdings in each title)
Reporting by Shreya Mariam Job in Bengaluru; Editing by Clarence Fernandez