Predictive modeling of wellbore temperature field in composite thermal recovery technology and its field implementation: a case study in Tahe Oilfield, China

In order to precise forecast of temperature fields in composite thermal recovery wellbores under the combined of "mixing light oil in annulus, cable heating, thermal insulation tubing, and thermal insulation cement", a temperature field model is established based on the radial heat transfer law of the wellbore under composite thermal recovery technology and whether occur the influence of heat sources, the vertical wellbore under composite thermal recovery is divided into two parts: the independent mixing light oil section and the mixing light oil section + cable heating section, and a segmented prediction model for the temperature field of the composite thermal recovery wellbore is established. Based on example calculations, the errors of the calculation are detected, and the sources of errors are elucidated through single factor and parameter analysis, deriving correction coefficients for different light oil to heavy oil ratios by inverting of measured wellhead temperature, which makes the calculation error has decreased from 16.82% to 3.80%. Based on the field application after heat-transfer coefficient correction, it is found that the composite technology has a 13.33 °C increase in wellhead temperature. The research can provide reference for the use of composite processes in ultra deep heavy oil extraction.