Energy stocks advanced Thursday afternoon, with the NYSE Energy Sector Index and the State Street Energy Select Sector SPDR ETF (XLE) each adding about 0.5%.

The Philadelphia Oil Service Sector Index was up 0.4%, and the Dow Jones US Utilities Index increased 0.8%.

In geopolitical news, China has privately asked Tehran to help rein in Yemen's Houthis after an appeal to Beijing by Saudi Arabia following the Iran-backed group's military blitz in the past week, three Iranian sources familiar with the matter told Reuters. Riyadh turned to China for help after the Houthis made rapid advances along the Red Sea coast and around the Bab el-Mandeb Strait, moves that have left Saudi oil exports and shipping more exposed, the sources told the news agency.

Front-month West Texas Intermediate crude oil shed 0.4% to $102.07 a barrel, and the global benchmark Brent crude contract fell 1.2% to $104.58 a barrel. Henry Hub natural gas futures rose 1% to $2.92 per 1 million BTU.

US natural gas stocks rose by 44 billion cubic feet in the week ended Sept. 11, a smaller gain than the 48 billion cubic foot increase expected in a survey compiled by Bloomberg and following an increase of 40 billion cubic feet in the previous week.

In corporate news, Hallador Energy (HNRG) shares jumped past 7% after it said Thursday that it closed up to $675 million in debt financing to fund the majority of its Turtle Creek Gas project cost.

National Fuel Gas (NFG) said its board plans to conclude an evaluation of a plan to separate the firm into two publicly traded companies by Oct. 15. Its shares were up 0.2%.

California Resources (CRC) said Thursday it agreed to sell its Uinta Basin properties to an unnamed purchaser for about $90 million in cash, effective July 1, with closing expected by the end of the year. California Resources shares were down 0.1%.