Qatar Petroleum is among the good employers in Qatar. I suggest you take the job first and settle down here. Then when you get married, the company may consider giving you family status. However, at this stage when the job is important, possibly the employer may not like some additional demands which may not be a part of the package. You may discuss with them your plans in a very diplomatic way without hurting yourself. It also depends on how strong is your background and the company's need to hire you.