Temperature Control Capability of Test Fluid Used in Offshore Operations

Deep water and HTHP have been two challenges encountered in the exploration and development operations in the west of South China Sea, and low temperature at the seabed and high temperature at the wellhead are difficulties that must be dealt with in offshore well testing. Study on the heat retaining test fluids has not been found presently in China. Through the construction of the heat transfer prediction model used in gas well testing, sensitivity analyses were performed to those factors of the test fluids affecting the temperature field in the borehole of deep water and HTHP gas wells, and a method of adjusting the temperature control capability of a test fluid was established. The maximum temperature prediction error of the model is only 3.4℃. Using this model and the method, a test fluid with adjustable temperature control capability and controllable wellhead temperature was developed. The test fluid has shear stress greater than 4 Pa, and has been successfully applied in an offshore deep gas well in the west of South China Sea. The measured wellhead temperature during well testing is 16.5℃, while the calculated wellhead temperature is 18℃, and the temperatures measured at the different places in the wellbore are very close to those calculated. Test of the well has been successful, giving gas production rate of 100×104 m³/d.