Subsea hydraulic control line reliability investigated

In general, downhole control lines are not subject to routine failures, but a study of downhole completion failures identified them as a principal failure cause. The cost of recovering downhole completions to repair control line failures warranted the investigation of equipment reliability including control lines, clamps and fittings. Early work indicated that the components were not engineered as a system, but rather as individual components driven by the hardware interfaces of more substantial components at the physical limits of the system. Hence, the mechanical attributes of the components collection had never been closely studied. To fill this knowledge gap, a system-level approach was developed to understand and resolve the problem areas. This article details that process. An integrated team of completions and subsea engineers found that the control line and its components may not be engineered to the same rigor as the rest of the subsea and completion system.