Callon Petroleum Co., Natchez, Miss., (NYSE: CPE) as has named Gregory Hepguler, senior reservoir engineer. He worked as an engineer with Southwestern Energy Co. on the Fayetteville shale gas fields in the Arkansas Arkoma Basin.

At Callon, he will working with geologists and providing predictive models for reserve reporting in the Wolfberry oil and Haynesville shale gas plays.

April Coker has been named development geologist. She has experience in the Permian Basin and will be involved in Wolfberry Field development planning and implementation.

John Becher has been named senior explorationist and will be responsible for assessment of new venture unconventional shale gas opportunities and will work with company engineers to provide accurate reserve estimates.

John Beddo has been named drilling and production superintendent. He has experience in the Permian Basin, the Wolfberry Trend and the Haynesville.

Eric Williams has been named manager, financial reporting.

Callon Petroleum has oil and gas properties primarily offshore the Gulf of Mexico with onshore assets in Louisiana and Texas.