what do you know about 'venssia petroleum' in saudi
arabia...ie..management? how long in business? how large an operation?
are there legitimate and if so contact address and telephone numbers?
do they have the capacity to export millions of barrels of crude oil
from saudi arabia.

Thank you for your question.  
 
However, I believe that to answer it well, your question will require
more time and effort than the average amount of time and effort
associated with this price. Here is a link to guidelines about pricing
your question, in the pricing guide:
https://answers.google.com/answers/pricing.html

1) 99.9% chance you are being scammed

2) Post more details eg:
   a) initial mode of contact
   b) how much you know about the oil business (why ask if you already know)
   c) Emails - with their headers - they can be very revealing

3) Do not pay anything

At least you had the sense to ask  - hopefully you have not yet been burnt.