* Deal includes large bundle of oil and gas assets
* Deal seen as major boost for Shell's drive to reduce debt
* To be announced within days, several banking sources say (Adds details, background)
By Ron Bousso and Clara Denina
LONDON, Jan 27 (Reuters) - Royal Dutch Shell isnearing the sale of a large part of its North Sea oil and gasassets to private equity-backed Chrysaor for $3 billion, bankingsources said, marking a milestone in its drive to reduce debtafter buying BG Group.
Chrysaor, a North Sea-focused oil company backed by privateequity fund EIG Partners, will acquire from Shell a mix of olderfields, new developments and infrastructure in a move analystssay could breathe new life into one of the world's oldestoffshore basins where production has been in a steady declinesince the late 1990s.
The anticipated deal in what is a relatively high-costregion has been seen by the industry as a litmus test for thesector's appetite for buying and selling oil and gas fields,known as upstream, as it slowly emerges from a brutaltwo-and-a-half year downturn. It could now unlock other deals inthe North Sea and other regions.
Shell and Chrysaor declined to comment.
The deal is expected to be announced in the coming days tocoincide with Shell's full-year results on Feb. 2, severalsources said.
Chrysaor will take charge of hundreds of Shell and former BGemployees that work on the platforms.
It will also become operator of several fields, highlightingthe changing landscape in the North Sea where oil majors such asShell and BP are finding it harder to make profits.
In November, Austrian oil and gas group OMV agreedto sell its UK unit to private-equity backed Siccar Point Energyfor $1 billion.
Chrysaor has been given the green light by Britain's Oil andGas Authority regulator to operate fields in the North Sea. Thedeal also includes an "innovative" structure to tackle theexpensive and complex decommissioning of platforms andinfrastructure once production in fields is ended, sources said.
For the Anglo-Dutch company, the deal could kick start astring of other upstream sales that have struggled to attractinterest throughout the downturn to help it meet its $30 billiondisposal target by around 2018 following the $54 billionacquisition of BG Group in February 2016.
Several companies have looked at Shell's North Sea portfolioin recent months including A.P. Moller-Maersk,petrochemical giant Ineos and private equity fund Carlyle Group,according to banking sources.
Shell's asset bundle includes a non-operating stake inBuzzard north of Aberdeen, a relatively new field that feedsinto the global Brent oil benchmark and a share in Shell's 55percent holding in the BP-operated Schiehallion oilfield some110 miles (180 km) west of the Shetland Islands.
Other assets include the Nelson, Armada, Everest, Lomond andJ Block fields, and Shell's stake in the Statoil-led Bressay development, according to banking sources.
Shell has sold or agreed to sell around $7.8 billion ofassets since announcing the deal in April 2015, though themajority of them were in the refining sector and infrastructure.
(Editing by Jason Neely and David Evans)