Oct 12 (Reuters) - Dealmaking in the U.S. oil and gas industry in the third quarter of 2021 fell from a two-year high in the previous quarter, according to data analytics firm Enverus on Tuesday, as the industry cools from post-pandemic consolidations and focuses on selling off non-core assets. Mergers and acquisitions (M&A) activity in the July-September quarter totaled $18.5 billion, down 44% from the second quarter, even as it beat the five-year quarterly average M&A value. "The sense of urgency seems to have left the deal market," Enverus director Andrew Dittmar said. "Through the end of the year, we are likely to see mostly smaller-sized asset deals as companies trim their portfolios with the chance of an occasional larger public company merger or private E&P sale."Oil producer Conocophillips (COP.N) led the quarterly ranks, the Enverus report showed, after it bought oil giant Royal Dutch Shell Plc"s (RDSa.L) assets in the Delaware Basin for $9.5 billion in September. Deals by private equity firms saw an uptick as they bought assets that oil companies deemed as non-core to their development plans, the report said, adding that such privately funded buyers increased their share of acquisitions to about one-fifth by value. These assets tended to lay outside oil-prolific areas like the Permian Basin of West Texas and New Mexico. "It was inevitable that the hungriest buyers and sellers would find their deals and activity would revert back toward the average. We seem to be hitting that inflection point," Dittmar said.