OPEC and non-OPEC oil producers, in an impromptu press briefing, reaffirmed their commitment to their production agreement Tuesday and expressed optimism there would be full compliance.

Saudi Arabia Energy Minister Khalid Al-Falih had warned earlier in the day that the kingdom would not bear the burden of the cuts and all 24 partners in the agreement would have to pull their weight. He said Saudi Arabia would not tolerate "free riders" and was now producing below the psychological 10 million barrels a day to keep its end of the bargain.

After two days of meetings in Houston at the CERAWeek conference by IHS Markit, Al-Falih said he and other ministers had bilateral and other meetings and were committed to their accord to remove 1.8 million barrels from the market.

The global oil industry, including major shale players, were present at the week-long conference, and the question repeatedly for OPEC members and Russia were whether there was compliance to the agreement and whether it might be extended in May.

Flanked by Russian Energy Secretary Alexander Novak, OPEC Secretary General Mohammad Sanusi Barkindo, Iraq Oil Minister Jabbar Ali Al-Luiebi and Mexico 's deputy oil minister Aldo Flores-Quiroga, Al-Falih said he was satisfied with the progress.

Al-Falih said he was also quelling concerns raised in Houston about shale production. There had been much talk about whether the resurgence of shale drilling would impact the OPEC agreement, which has stabilized oil prices above $50 per barrel.

"The comeback of shale to a certain degree is not only welcome and acceptable but is necessary because of demand growth and the decline elsewhere," Al- Falih said.

Earlier in the day, Al-Falih told a CERAWeek audience the market can absorb another 3 million to 5 million barrels a day of U.S. oil "over a number of years."

Each minister in the room affirmed commitment to the OPEC agreement. Earlier, Iraq's oil minister said after raising production to 4 million barrels by the middle of 2016, Iraq would reach 5 million barrels a day by the second half of this year.

Analysts have said it's unclear what Iraq was actually cutting back from the world market. Its output has risen but it has also reclaimed some of its territory.

"I am a perfectionist and and I always seek 100 percent delivery," said Al-Falih during the Tuesday evening press conference. He said they are not there yet, but he said he has been reassured that where there are gaps, they will be filled.

Barkindo said many of the questions revolved around the fact that there is so much inventory remaining. U.S. weekly data shows a consistent glut in the United States and a big pickup of activity among U.S. producers. However, he said it is important to look at offshore data that is beginning to show declines.