Abstract: In order to realize the economic and efficient development of offshore heavy oil reservoir,by taking N oilfield in Bohai as an example,based on the geological reservoir characteristics and production performance of N oilfield,a study on the influencing factors of multiple thermal fluid huff and puff production capacity was carried out by combining numerical simulation with orthogonal test design.The results show that the main factors that influence the initial productivity of huff and puff are the viscosity of crude oil,the effective thickness of reservoir and the effective permeability of reservoir.The influencing factors of production parameters(dynamic influencing factors) on the initial production capacity of multiple thermal fluid stimulation,mainly includes production pressure difference,CO_2 composition and horizontal well section length.Among them,the influence degree of each factor is followed by production pressure difference,horizontal well section length,and CO_2 composition.At the same time,the optimal combination scheme of geological reservoir parameters and production parameters is further defined,so as to provide guidance for the study of multiple thermal fluid productivity evaluation.