Oil and gas companies still stinging from last year’s deal price inflation - an increase of 55 percent from 2005 - may welcome the M&A slowdown that has come with a tightening of credit markets if it helps lower demand.

Driven by the need to put more reserves on their books, oil and gas companies fought each other and private buyers for assets, spending 80 percent more than a year earlier for just a 15 percent increase in proved reserves.

In all, they spent $91.8 billion on proved reserves, up from $51.5 billion a year earlier, according to a report from John. S Herold, a petroleum research company, and Harrison Lovegrove & Co., an energy corporate advisory firm.

Oil and gas companies also decided it was time to be more risky in what they did buy, nearly doubling their spending on unproved reserves to $47.4 billion from about $24 billion a year earlier.

They also increased the percentage of spending overall to build reserves that came from unproved properties to 12 percent in 2006 compared with 6 percent a year 2002, cutting back on development and exploration spending.

ConocoPhillips was the biggest spender of all, shelling out $42 billion for both acquisitions and development - three-quarters of which was on purchases. Much of that was wrapped up in its $34 billion acquisition of Burlington, the value of which has been questioned by many analysts.

Even after all that spending, oil and gas companies are still facing the same issues of growing reserves that they have always dealt with. Reserves for the 228 companies worldwide the report covered were up only 2 percent in 2006.