** Oil and gas stocks rise on positive Chinese factory data, rising energy demand and hopes for U.S. economic stimulus
** Brent crude was up 1.3% at $44.98 a barrel, while U.S. West Texas Intermediate crudewas up ~2% at $42.03 per barrel
** Shares of oil major Chevron Corp and Exxon Mobil Corp rise 2.1% and 1.3%, respectively
** Oil producers Callon Petroleum, Marathon Oil, Whiting, Cabot Oil & Gas, Occidental Petroleum climb between 2% and 6.3%
** Top oilfield services firms Schlumberger NV and Halliburton gain over 3% each
** Saudi Aramco is moving ahead with plans to boost its oil output capacity by 1 million barrels per day (bpd) to 13 million bpd, despite spending cuts this year and next year, its chief executive said
(Reporting by Arundhati Sarkar in Bengaluru) ((Arundhati.Sarkar@thomsonreuters.com; twitter.com/Arundhati_05))