As one of the offshore heavy oil thermal exploitation technology

the multi thermal fluid stimulation technology had been carried out in the development of heavy oil in Bohai oilfield. By the theoretical analysis and numerical simulation method

we reasonably characterized the mechanism of multi thermal fluid huff and puff

introduced the concept of coefficient of variation

and obtained the main factors affecting the effect of multiple rounds of throughput

which were the injection strength

shift opportunity

injection temperature

and periodic increasing rate. Based on the reservoir characteristics of the typical oil field

and with the evaluation index of the rate of cycle output and input

we got the sample data of different cumulative oil production and gas retention conditions

and regressed the optimum injection strength in multiple cycles of multi thermal fluid huff and puff wells. Then we corrected the optimization by using the main factors influencing the thermal recovery effect

drew the optimized version to obtain the reasonable injection parameters accurately and efficiently

and improved the thermal recovery effect of huff and puff in multiple rounds.