General Electric has named Lorenzo Simonelli as chief executive of its oil and gas unit, replacing Dan Heintzelman, who was appointed a vice chairman of the company.

GE has spent over $14 billion since 2007 on acquisitions to build up its oil and gas business, which is the company's fastest growing, with $15 billion in revenues.

"Simonelli has done a good job of trying to bring an underperforming unit into a profitable and growing business for GE," Morningstar analyst Daniel Holland said. "Moving him to energy puts him more in investors' eyes." In his new role, Heintzelman, 56, will focus on services and operations.

Russell Stokes will replace Simonelli, 40, as CEO of GE Transportation.

"Lorenzo transformed GE Transportation from a North American rail business to a global transportation equipment and solutions provider," said Jeff Immelt, GE's CEO. The company is focusing on its core industrial sectors such as energy.