A PHd isn't going to do much for you. Ask yourself - I am employer and I am employing someone to work in a refinery (or maybe advising in the construction of one) or perhaps someone to work as a geotech engineer in Brazil. Why would I need you to have a PHd? What would I need you to have "Dr" in front of your name for? What benefit would that bring me an an employer?
The wheels of industry (petrochem, oil, gas, mining etc) revolve because these industries are managed by people who are well educated and experienced - Chartered/Professional Engineers who have been around the track a few times - not because they are full of egg heads. A PHd is great if you want a personal challenge or if you want a life in academics (paying a fraction of what you could earn in industry to teach)