Oil prices may have seesawed for most of last week but ended on a solid note with the OPEC members announcing a smaller-than-expected output raise on Jun 22. The proposal to hike output was placed by Saudi and Russia.OPEC members reached a deal in the Vienna meeting to return to 100% agreement to the previously agreed output cuts. However, no concrete figures have been provided. Investors should note that on Nov 30, 2016, the OPEC cut a deal, per which, the bloc would have cut production by about 1.2 million barrels per day (bpd) from January for six months (read: How Effective is the OPEC Deal for an Oil ETF Rally?).Saudi Arabia said the renewed deal would result in a nominal output rise of around 1 million barrels per day (bpd), or 1% of global supply. Iraq, however, said, the real increase would be a little less at around 770,000 bpd as many countries would strive to attain full quota.Since the actual output increase came in lower than expected, oil price rallied. “People probably feared 1.5 million barrels a day.” Now a real output boost of about 770,000 bpd has come as a real relief to space. Saudi Energy Minister Khalid al-Falih indicated that there will be no "immediate flood" of oil in the market.WTI crude ETF United States Oil USO and Brent fund United States Brent Oil BNO gained more than 5% and 3.7% on Jun 22, respectively. Declining stockpiles favored WTI crude more than Brent while lack of clarity in details of the agreement or numbers sent Brent on a backfoot (read: Is $100-a-Barrel Oil Possible? ETFs in Focus). What Drove the Need for Output BoostUnder the ongoing output cut deal, OPEC, Russia and other producers agreed to reduce output by 1.8 million barrels per day. But OPEC reduced more than the requirement. OPEC compliance was 152% in May, resulting in an additional output cut of about 624,000 barrels a day.This shortage seems not to have met market demand properly (in the wake of increasing global demand) and forced the cartel to pump more. Also, to make up for the supply loss from Venezuela and Iran, the latest output boost deal has been finalized.Per James Williams, the energy economist at WTRG Economics, the deal will add that 624,000 bpd from OPEC members jointly. However, the contribution from Russia and other allies will take the number somewhat higher.ETFs in FocusHaving said all, the immediate impact on the oil patch was positive right after the OPEC meeting. Against this backdrop, below we highlight a few regular energy ETFs that have returned the most on Jun 22.Invesco Dynamic Oil & Gas Services ETF (PXJ)– Up 4.1%SPDRÂ S&P Oil & Gas Equipment &Services ETF (XES – Up 3.97%VanEck Vectors Unconventional Oil & Gas ETF FRAK – Up 3.58%VanEck Vectors Oil Services ETF OIH – Up 3.48%iShares US Oil Equipment & Services ETF IEZ – Up 3.36%SPDRÂ S&P Oil & Gas Exploration & Production ETF XOP – Up 3.17%Want key ETF info delivered straight to your inbox?Zacks’ free Fund Newsletter will brief you on top news and analysis, as well as top-performing ETFs, each week. Get it free >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report ISHARS-US OIL E (IEZ): ETF Research Reports SPDR-SP O&G EXP (XOP): ETF Research Reports VANECK-OIL SVC (OIH): ETF Research Reports VANECK-UNC O&G (FRAK): ETF Research Reports SPDR-SP O&G EQP (XES): ETF Research Reports PWRSH-DYN OIL&G (PXJ): ETF Research Reports To read this article on Zacks.com click here. Zacks Investment Research Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report