FRANKFURT/LONDON/VIENNA, Jan 22 (Reuters) - Abu Dhabi National Oil Co (ADNOC) and Austria's OMV are poised to resume talks to agree final terms of a tie-up that would create a chemicals group with more than $20 billion in combined annual sales, sources close to the deal said.

Three people with knowledge of the situation said there are still outstanding terms to agree on, with two of them saying that the companies planned to resume talks possibly as soon as this week.

OMV said in July last year it had entered into talks to merge petrochemicals group Borealis - which is owned by OMV and ADNOC in a 75:25 split - and Borouge, which is listed in Abu Dhabi and 54:36 owned by ADNOC and Borealis.

The two sides had been close to agreement, sources told Reuters previously.

But a number of sticking points remain, including a provision for job guarantees in Austria, a requirement for a Vienna listing and an Austrian chairman of the new company, two of the people said, speaking on condition of anonymity.

A dual listing in Vienna and the UAE could be an option, a fourth person said.

An OMV spokesperson said the two sides were in "ongoing negotiations."

In October, the Austrian company's CEO Alfred Stern said the company would be listed on the stock exchange.

A deal is still expected to happen as the obstacles are surmountable, three of the people said.

The terms of the deal would also include a capital infusion to ensure both parties have the same equity share in the new company, Reuters reported in December.

Previously OMV said both Borealis and Borouge would become "equal partners under a jointly controlled, listed platform for potential growth acquisitions to create a global polyolefin company".

OMV is partly state-owned and has Abu Dhabi's Mubadala as its second largest shareholder. Mubadala's shares in OMV will be taken over by ADNOC, as previously announced.

Separately, state-owned ADNOC said on Monday it would allocate $23 billion for decarbonisation and lower-carbon projects, up from a previous $15 billion target. (Reporting by Emma-Victoria Farr, Ron Bousso, and Alexandra Schwarz-Goerlich. Additional reporting by Anousha Sakoui. Editing by Jane Merriman)