Apache Corp is exploring a sale of a stake in its shallow water Gulf of Mexico assets, attracting private equity interest as it looks to reach a $4 billion asset sale target, several people familiar with the matter said.

Apache has hired Goldman Sachs Group Inc to sell a minority stake in its oil and gas assets located on the shallower continental shelf region of the Gulf, the people said. These assets currently produce more oil and gas and are easier and less risky to exploit than their deepwater counterparts.

The shelf assets appeal primarily to financial investors, the people said. TPG Capital LP, Apollo Global Management LLC and KKR & Co LP are among the private equity firms mulling offers for them, they added.

Some of the people spoke on Tuesday and others spoke last week. They asked not to be identified because details of the processes are confidential.

An Apache spokesman declined to comment on the sales processes, but noted the company has announced an asset sale program. Goldman Sachs also declined to comment. Jefferies, Apollo, TPG and KKR did not immediately respond to requests for comment.

(Reporting by Greg Roumeliotis and Michael Erman in New York. Editing by Andre Grenon)