Yes, you can claim per diem if your work in Saudi Arabia is expected to last less than one year. The determining factor is not how long you are at the work site during the year, but how long the job will last.
In Publication 511, the IRS says:
Generally, your tax home is the entire city or general area where
your main place of business or work is located, regardless of where
you maintain your family home. For example, you live with your family
in Chicago but work in Milwaukee where you stay in a hotel and eat
in restaurants. You return to Chicago every weekend. You may not deduct
any of your travel, meals or lodging in Milwaukee because that's your
tax home. Your travel on weekends to your family home in Chicago isn't
for your work, so these expenses are also not deductible. If you regularly
work in more than one place, your tax home is the general area where
your main place of business or work is located.
The article below explains in more detail how the IRS rules work.
https://ttlc.intuit.com/replies/5018439
