Marathon Oil Corp. (NYSE: MRO) said Aug. 22 J.R. Sult, executive vice president and CFO, elected to leave the Houston company for personal reasons.

Sult's departure, which will follow an appropriate transition period, is not related to any disagreement with Marathon regarding financial disclosures, accounting or business matters, the release said.

Pat Wagner will hold the role of interim CFO while the company conducts a search for a new CFO.

Wagner, vice president of corporate development and strategy, joined Marathon in 2014. He has extensive financial and operational experience, including senior roles at QR Energy LP, Scotia Waterous, and Devon Energy Corp. (NYSE: DVN), the release said.

Marathon also promoted T. Mitch Little to executive vice president of operations. Little, currently vice president of conventional, will now oversee Marathon's resource play and conventional businesses.

Having joined Marathon in 1986, Little brings deep E&P knowledge via a number of engineering, subsurface and management positions across the company's U.S. operations in Oklahoma, Wyoming, Louisiana and Alaska and internationally in Equatorial Guinea, Gabon and Libya, according to the release.

He previously served as managing director of Marathon Oil Norge AS and general manager of worldwide drilling and completions.

In conjunction, Lance Robertson, vice president of resource plays, also elected to leave the company to pursue other opportunities, the release said.

Cathy Krajicek, currently vice president of technology and innovation, has accepted the role of vice president of conventional. Bruce McCullough, currently vice president and chief information officer has accepted the role of vice president of technology and innovation. McCullough will retain his role as chief information officer.

All leadership changes are effective immediately, the release said.