I do agree with Han19. Being a civil engineer with 20 yeas of experience, u should get atleats 15-20K as base salary+accom(preferable company flat)+transpo+health+air tickets for urself and your family+education etc

So, ur package should be around (atleast)35k QR. If anything less than that, i would say you are going below the market value. It is worth mentioning here one fact that, here in Middle East you will be paid based on your nationality and what kind of passport you hold as well.
Dont be in rush in finalising any offers, discuss with qatar living forum, there are plenty of big brains sitting here and advsing people who have any queries.

Good luck Sub.

cheers
krish