Abstract: Abstract：With the development of oil economy，the exploitation of offshore heavy oil is getting more and more attention.
Multiple thermal fluid huff and puff is an efficient and economic heavy oil production technology，which has been applied
with success in Bohai Oilfield. In this paper，based on the experimental wells of M Oilfield，the technology characteristics and
the production effect are introduced；wellbore temperature distribution model and complex heat transfer coefficient calculation
method are studied. In addition，the optimum design method for several important process parameters of the multiple thermal
fluidhuffandpuffarepresentedsuchasinsulatedtubingheatconductioncoefficient，insulatedtubingsettingdepthandmultiple
thermal fluid compositions. Through the study，some useful conclusions of multiple thermal fluid huff and puff have been
acquired，which could be used to guide the thermal recovery plan optimization design of offshore

Key words: Key words：offshore oilfield, heavy oil, multiple thermal fluid, huff and puff, thermal recovery