Subsea Condition Monitoring: Does Effective Diagnosis Increase Availability?

Abstract

Management The challenges encountered in deepwater development have led to the use of increasingly complex subsea systems. Consequently, operators have become more reliant on subsea monitoring equipment and instrumentation to provide field information for understanding production and equipment conditions. Production monitoring is typically the field operator’s main priority, and equipment condition and performance are sometimes overlooked, resulting in equipment failures and long production downtimes because of unplanned maintenance. Equipment failures often occur without warning and may sometimes, when caused by environmental factors, become inevitable. To determine the cause, field operators sift through vast amounts of distributed data from the subsea control system. The system downtime can be reduced and system availability can be increased by performing effective equipment diagnosis. With the current low-oil-price environment, subsea operators are looking to maximize returns on investment, and condition-based monitoring offers the possibility of lowering operational expenses while increasing field production. Condition Monitoring Condition monitoring is a proactive maintenance strategy combining software and people. Data are used to diagnose changes in the integrity of a system such that corrective action may be planned in a cost-effective manner to increase system availability. Condition monitoring is not a novel technology and is currently used in the aeronautical and automobile industries. The condition monitoring system takes integrity monitoring beyond traditional key performance indicators by utilizing all available data and information from the system and looking for trends of equipment degradation prior to equipment failure. A condition monitoring system is typically based on the following three-step monitoring process: Data Collection: Read-only software to acquire real-time and historical knowledge from the subsea control system. Storing historical data and supporting analysis based on historical trends. Analysis: Onshore analysis server applies statistical analysis, signal processing, mathematical modeling, and simulations to ascertain system conditions. Requires experience-based product knowledge and reliability analysis to target known failure modes and performance issues. System may be tuned and updated in order to continuously improve its online diagnostic performance. Collaboration and Discussion: Estimation of potential impact on production (availability) is built into the system based on operational and maintenance philosophy. With remote surveillance, multiple onshore and offshore users are able to operate the system on a web-based graphical user interface for monitoring and troubleshooting of the subsea field. To simplify monitoring, each component and associated potential failure mode is designed with its individual user interface.