(GRE Success! ) US or Canada for Chem./Pet. Eng. _ Pros and Cons???

Dear friends,
Many thanks to Srihari's helps, I restate my question, as I think may be some friends skipped the last E-mail due to the not engaging subject. 


I have a Master's in Chemical Engineering and am applying. Now I see two ways in front of me:
1- Applying for a Master's in Petroleum Engineering
2- Applying for a Ph.D. in Chemical Engineering

For each of the alternatives, I think of US and Canada.



I would be grateful if anyone can possibly share his or her valuable knowledge with me. Has anyone experienced a similar query?
Any
advise about choosing between US or Canada would be of great help.
(Regarding the job market and citizenship procedure and duration)




Sincerely,
Anahita