Frank Hartley,
Drilling & Production Editor
HOUSTON -- Operations of a high-pressure high-temperature (HPHT) wells may expose the hydraulic control line (HCL) in the wellbore annulus to significant pressure and temperature changes, which can cause severe pressure across the wall of the HCL, said C.T. Zhao with Technip at the 2008 Offshore Technology Conference in Houston. He continued to say in order to prevent the associated control-line failure (burst or collapse) and high repair cost, the maximum pressure differential across the wall of hydraulic line needs to be determined at the design stage for the worst scenario, including the situation when normal operation cannot be followed.
Zhao says that the pressure change across the wall of a control line is the result of many coupled factors such as pressure temperature in the wellbore annulus, well profile and constraints on the HCL; compressibility of fluid HCL; thermal expansion of the HCL; and related stress-strain variation of the HCL.
05/07/2008
