Grad School In The Us

That depends on your interest, If cash is a problem , go for a school where you can do an assistantship and forget the Pricey private institutons unless you have a sponsor with plenty of kudi. As for the course to study, go for something you will enjoy then the dough will come in.
You had nice scores in the GRE.

@b2dl,
   Why not post your profile here so we could be able to advise?First of all,you need to write your GRE and TOEFL.Those are basic requirements.For oil and Gas in the states,try the universities in texas.
  University of Texas at Austin
  University of Texas A&M
  Stanford University.
These unis rock in the oil and Gas sector.
@dayokanu
  Bravo!!!The scores you got are ok.It can find u a place in nice schools abrod.If you want Petr Engr try the above mentioned universities.How's your Undegraduate CGPA like,esp in your major?your profile will help  you receive good suggestions.

for oil and gas, all things considered i say you opt for texas a&M. you can get them online at www.tamu.edu. Texas is an oil state (like PH) and the good thing is that they (university) have a lot of businesses in the oil sector that helps out in IT, field trip, jobs etc.

however as with anything, ABILITY TO PAY IS THE ISSUE. YOU WILL HAVE TO CONVINCE THE EMBASSY. that is the sticky point.

Good luck