Effect of the variation of phase-transition fracturing fluid thermophysical properties on the wellbore temperature

Abstract

Accurate prediction of wellbore temperature is the key to ensuring the success of self-propping phase-transition fracturing (SPF) technology, which uses two immiscible fluids to form solid proppant in the hydraulic fracture. Since the thermal-sensitive physical parameters of the two immiscible fluids significantly influence the wellbore temperature distribution, a wellbore temperature model considering reaction heat is established, and the mathematical relationship between the physical parameters of fluid and temperature is introduced. The exemplary cases are analyzed to assess the influence degree of those factors on wellbore temperature distribution. The results show that the reaction heat exerts the most critical effect on the wellbore temperature; the specific heat capacity effect is ranked second, while the influence of density is small. As to the coupled effect of the three factors, its influence degree is between those of the reaction heat and specific heat capacity. Therefore, the wellbore temperature must be predicted considering the influence of reaction heat and the varying specific heat capacity and density to ensure the smooth injection of the phase-transition fracturing fluid system (PFFS). These findings could help reveal the action mechanism of reaction heat and thermal-sensitive physical parameters in the heat transfer process, which is of great significance for the theoretical research and field implementation of the SPF technology.