The Oil & Gas industry is not sexy and never will be, but it pays well above market and people with niche skills will do very well there (as you have no doubt now seen).
Technological progress in the space tends to move pretty slowly (especially on the Operational Technology side of the business) owing to many factors, but mainly risk avoidance. The flip-side of this is that once one company adopts a technology, the others tend to follow suite, so what you're doing may be very portable should the need arise.
Another benefit of O&G is that due the the specialised nature of a lot of the roles, you'll keep running into the same people at different organisations throughout your career, so keep your keep expanding your network along the way.
Don't let your perception of slow growth worry you too much - on the technology side, progression will come naturally as you take on new and more challenging projects. As a tech in a very different field, but a similarly isolated environment, I too have had these thoughts throughout my career, but remember there is a big wide world outside of silicon valley, and plenty of successful careers to be had.
It sounds like you have a boss you like who you could learn a lot from - this is huge. I'd focus on getting him to teach you to become a domain expert in the Oil & Gas space. This combined with your (relatively) niche technology skills will make you a unicorn in the future and combined with your network, pave the way should you want to become independent in years to come.
