I am a civil engineering graduate too. I would advise you to remain where you are for two reasons.
First, Sapiem's bond of at least thee years makes no sense to me. Only companies or organizations that are insecure or are unsure of their future will coerce their employees to sign a bond. The pay of 80k is not in any way commensurate when compared with the hard-work involved (at least for now you are earning about 160k).What if you get a better offer within the next three years?
Second, there is no security in the oil and gas industry in Nigeria presently. The future is bleak for oil as a major source of energy in a few years to come.
Wishing you the best in your career prospects.