Simulation of wellbore temperature and pressure field in supercritical carbon dioxide fracturing

As unconventional oil and gas receive more and more attention, scholars pay more and more attention to waterless fracturing technology. Among them, carbon dioxide fracturing technology, as the main representative of waterless fracturing technology, has unique advantages and broad application prospects in the development of unconventional oil and gas reservoirs. However, when using carbon dioxide fracturing fluid for construction, carbon dioxide is greatly affected by temperature and pressure, so it is necessary to simulate the temperature and pressure in the wellbore during carbon dioxide fracturing construction. In this article, the basic physical properties of carbon dioxide under different temperatures and pressures are analyzed, and the changes of wellbore temperature and pressure during carbon dioxide fracturing are studied based on the generalized heat conduction theory. The results show that the faster the injection rate of CO2 fracturing fluid at the wellhead, the lower the bottom hole temperature and the higher the bottom hole pressure. However, the higher the wellhead injection temperature, the higher the bottom hole temperature, and the lower the bottom hole pressure.