Design and Validation of an Improved Shunt Tube System

Abstract

Shunt tube technology to mitigate premature bridging in the annulus while pumping slurry has been used successfully in the oilfield for over two decades to assure complete gravel placement. The systems have been applied in a variety of scenarios including single and multizone completions, cased and openhole completions, and both gravel and frac-pac applications. By deploying a screen system empowered with the slurry bypass mechanisms of a shunt system, an operator usually experienced greater job reliability, a reduced possibility of pack failure, and maximized production.This paper discusses an improved version of the traditional shunt tube system that has recently been developed by a major engineering and service company to enhance sand screens for gravel packing in long production intervals. The system was designed primarily for gravel packing in horizontal wells and is a system with two larger transport tubes and two smaller packing tubes, all mounted to standard sand screens in an eccentric design. A new seal design improves sealing capability between the joints of screen. By the optimization of the attachment of the tubes to each other, to the rings mounting the system to the screen, and to the sealing fittings at the transport tube ends, the design significantly enhances system capabilities.Computer flow modeling was used to improve erosion resistance and lower pressure loss by reducing friction at tube connection flow transitions. Extensive test programs to ensure equipment integrity, including torque, tension, and compression capability of major components were used. The system can be assembled more quickly due to the shroud covering the joint connection being an integral component of the screen with no bulky clamshell hinges or pins to be assembled.The improved pressure sealing, erosion resistance, ruggedness, improved rig assembly times, and system qualification will be presented in the paper.