HOUSTON, Oct 16 (Reuters) - U.S. oil mergers slowed

sharply last quarter after a year-long consolidation wave

emptied pocketbooks and left fewer companies on offer in the top

U.S. shale field, analytics firm Enverus said on Wednesday.

There were $12 billion worth of deals disclosed in the

quarter ended Sept. 30, the lowest total in six quarters, said

Enverus Intelligence Research principal analyst Andrew

Dittmar.

"Upstream M&A was bound to drop" after 2023's record $192

billion in deals largely in the Permian basin of West Texas and

New Mexico, the largest U.S. shale field. Those mega deals have

acquirers busy running portfolio reviews to weed out unwanted

assets, he added.

Some of the biggest buyers have become sellers as they prune

holdings, he said, citing Occidental Petroleum's ( OXY ) $818

million sale of properties to Permian Resources ( PR ) and APA

Corp ( APA ) divesting older properties to an undisclosed

buyer.

The two biggest deals in the quarter were outside the Permian

basin in secondary shale fields, with Devon Energy ( DVN )

adding to its North Dakota holdings with a $5 billion deal for

Grayson Mill Energy assets.

The second largest deal, Quantum Capital Group's $1.8 billion

deal for Caerus Oil & Gas properties, was for properties in

northwestern Colorado and Utah.

"There is still a significant amount of oil and gas to

develop outside the main shale plays," said Enverus' Dittmar.

"We're going to see more interest in these types of assets from

private companies and small public companies."

The third quarter's deal value was the smallest quarterly total

this year, and less than half the second quarter's $30 billion

in oil and gas deals.

Some of the announced combinations have been delayed, either by

antitrust regulator the Federal Trade Commission or a contract

arbitration challenge.