Model Calculations and Factors Affecting Wellbore Temperatures During SRV Fracturing

Wellbore temperatures decrease dramatically during simulated reservoir volume (SRV) fracturing, which endangers the casing. Here, we establish a calculational model for wellbore temperatures based on heat-conduction theory and the characteristics of SRV fracturing. The results demonstrate the following relationships between the wellbore temperature and various factors: (1) With increasing pumping time, the wellbore temperature decreases gradually. (2) Increasing the pump rate can cause the wellbore temperature decrease. (3) As the initial temperature of injection fluid and the geothermal gradient increase, the wellbore temperature rises sharply. (4) The wellbore temperature increases slowly with the casing diameter. We analyze field tests and case studies in this paper, and the results show excellent agreement between the predictions and the measurements. The theoretical model can thus predict the wellbore temperature satisfactorily for fracturing operations.