Meet the team behind Greg’s Petroleum Service. We are a group of individuals who are passionate about the petroleum industry, and who are committed to delivering value through high quality products and exceptional customer service. To put it simply: we love what we do, and who we do it with.


Ron Mariani
President & CEO
Since 1979
Kelvin Gregory
Senior Sales Consultant
Since 1993
Greg Mariani
Sales Manager
Since 2016
Chris Gregory
Business Development Manager
Since 1996
Bob Harris
Fuel Operations Manager
Since 2012
Connor Swainston
Oil Operations Manager
Since 2014
Jenn Hayslett
Marketing Manager
Since 2017


Jim Alexander
Retail Brand Manager
Since 2011
Ron Binger
Commercial/Trucking Sales
Since 2011
Billy Delay
Commercial/Ag Sales
Since 2014
Mike Gutierrez
Junior Salesman
Since 2018
Darla Hall
Retail Lubrication Manager
Since 2010
Marcos Hernandez
Valvoline Chemical Manager
Since 2015
Aryana Trams
Cardlock Fuel Consultant
Since 2017


Angelica Galvan
Human Resources
Since 2002
Patricia Helvaci
Accounts Payable Manager
Since 2018
Tristan Regan
Cardlock & AR Manager
Since 2008
Miguel Rios
IT Manager
Since 2014
Todd Hall
Safety & Compliance Manager
Since 2012


Bob Harris, Joey Long, Jorge Ramirez, Christian Mastrocinque, Jordan Fitch & Chris Gregory
John Adams & Connor Swainston


Bill Mimnaugh, Ralf Leyva, Don Apple, Nick Whitton, Manuel Arambula & Jason Jarret
Bryan Roth & Irvin Pollorena