Abstract: Feasibility study on transmission capacity of a submarine oil pipeline with 5×10⁴m³/d from LD10-1CEP to offshore terminal is made with OLGA2000 multiphase flow unstable state simulation software. Calculation results show that blending transportation ofoil and gas is feasible in technology, although slight slug flow will form in the pipeline, but install a separator or slug catcher at the offshore terminal will control the slug flow. Through calculation, theoretical minimum volume of the separator is 33.76 m³ and volume of the separator is 50.63 m³ when safety coefficient is at 1.5.