Pressure and temperature prediction of transient flow in HTHP injection wells by lax-friedrichs method

The authors present a system model of partial differential equations concerning the variation of the pressure and temperature at different time and depth in high temperature-high pressure (HTHP) gas wells. Finite difference methods with Lax-Friedrichs scheme are improved to solve this set of conservation equations. The basic data of X Well (HTHP well), 7,100 m deep, located in Sichuan basin, Southwest China, is used for case history calculations. Gas pressures, temperature curve graphs along the depth of the well are plotted at different time. Comparing with the results without considering the influence of heat-transmission, the calculating results are more fitting to the values of real measurement. The comparison indicates that the new method is of high accuracy.