Study on the wellbore temperature distribution characteristics during foam drilling

In view of the specific properties of foam drilling fluids, a wellbore temperature calculation model during foam drilling has been established in this study, considering the Joule-Thomson influence, heat generation by pressure drop of nozzle, frictional heating between drill bit and formation, and frictional heating during foam flow. In addition, the solution of this model is solved by coupling method. Through calculation with examples, the results show that at the shallow well section, the foam temperature in annulus is higher than the formation temperature, and at the deep well section, the foam temperature is lower than the formation temperature. With the increase of liquid injection rate and gas injection rate, the foam temperature in annulus at the downhole and in coiled tube decreases, and the foam temperature in annulus at the wellhead increases. The foam injection temperature has a significant influence on the foam temperature. Increasing the injection temperature can improve the foam stability at the downhole.