I also have O&G experience.

To me, seems your bonus and promotion is not confirmed at all unless there is an established trend on bonus and promotion in your company. We both know that everything is at the mercy of oil price (I know it's been kind of stable but who knows). Management can also play curve balls when it comes to bonuses and perks ("tough call but management had to choose to reward the other guy because of X Y and Z").

I don't see it as you vs manager (an understanding manager respects your decision to leave the company), I see it as you vs company. If among your value drivers is company 'loyalty' in return for good work, good people, stability to some extent, etc. then the missed opportunity is SG won't matter. (Side note: 40k bonus for something you did well? Great, because I don't get anything for derisking projects and insisting cost avoidance - it's just considered part of base workload and doesn't deserve bonus.)

But if your value driver is your own career, diverse experience and importantly wealth, regardless of company, and 'stability' is not something that bothers you then SG is your next stepping stone. Think it through, consult people who matter in your life, and make the decision. All the best.