I understand why you wouldn't take those, but I would. Especially in oil and gas, it's almost impossible to get a job/internship without a masters degree. I think at those costs, the benefits of the degree outweigh the costs. Also, it's extremely competitive to receive full funding from mid tier schools or higher. Retaking the GRE will also do little to improve chances unless you do dramatically better. I have a friend who took a year off to work a mudlogling job and retake the gre. He ended up doing both and still didn't receive any funding.
Edit: yes, mudlogging can be counted as an O&G job, but no one wants to do that for a living.