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A reliable downhole flow-control system is essential for any intelligent completion. Generally, systems that meet the sought-after criteria are installed permanently in severe downhole environments and are not expected to be retrieved for analysis or maintenance despite harsh conditions. The entire system must achieve high operational reliability at temperatures as high as 200° C and pressures that reach 30,000 psi. This paper discusses the electro-hydraulic module of a reliable control system, which optimizes reservoir performance and enhances reservoir management capabilities by allowing the operator to remotely control the wellbore and obtain real time sensor data (which includes pressure/temperature). In order to meet the necessary system reliability targets, a Design for Reliability (DfR) process is applied in the form of a systematic, streamlined, and concurrent engineering program to assess the system's capabilities. A DfR is considered to be an integrated process rather than a step task for the design and development of the electro-hydraulic control module. The DfR process identifies the utility of reliability engineering tools and methods during the product development cycle. The objective of DfR is to meet the reliability expectations and optimize the overall life-cycle costs. This paper discusses the methods and tools of DfR and highlights the successful application of key DfR tools and techniques in the development of the electro-hydraulic control module. A variety of reliability tools were applied in the development cycle which includes (a) reliability requirements and flow down, (b) reliability block diagram for system reliability modelling, (c) design FMEA (failure mode and effect analysis) for design-based risk assessment, (d) baseline predictive reliability modelling, and (e) reliability qualification test design. This paper will focus on how to apply the DfR process in the product development. It will also highlight the process steps required to make DfR a powerful and effective process that can help any organization design reliability into its products. The DfR process can be applied efficiently by taking the strengths and limitations of its tools into consideration. In order to enable an effective and efficient application of the DfR process, the order in which various reliability engineering tools are applied is important.

Flow control devices (FCD) play a vital role in an intelligent completion’s ability to enhance reservoir management capabilities by allowing the operator to control inflow and outflowremotely. Among FCDs, the most versatile type is electrohydraulic. However, because these electrohydraulic FCDs are permanently installed in severe downhole conditions, it is important to integrate the reliability qualification testing (RQT) in the overall development effort. This paper describes a novel approach to product development which integrates RQT as a key component. RQT incorporates testing for all criteria, including function, environment, and reliability. It typically includes accelerated testing, which is performed to reduce testing time while helping ensure product reliability is verified. RQT is applied in the form of a systematic, streamlined, and concurrent verification program to help improve the reliability of the product. Design for reliability (DFR) tools, such as FMEA (failure mode and effects analysis), help identify the key failure modes and failure mechanisms (causes of failure) related to the product. It is of utmost importance to understand these failure mechanisms in detail and correlate them to the stresses applied during testing. RQT planning uses the analyses performed during the design phase, such as FMEA, reliability predictions anddevelopmenttesting results, to highlight the risks associated with the product. And, further integrates this information to efficiently design the tests. The primaryobjective of RQT is to determine whether the product will meet the mission reliability target. RQT planning not only identifies the need for component reliability testing, but also substantiates reliability targets at the component level. Multiple ingredientsare required todevelop an efficient RQT, such as (a) performing risk-mitigation studies during design phase, (b) defining a mission reliability target at the system and component level, (c) addressing the range of environmental conditions, (d) using accelerated test plans, (e) optimizing test parameters, sample size, test time, etc. This paper presents an efficient RQT plan, developed for FCD, as well as all associated accelerated testing models for system reliability predictionsand statistical confidence. Also discussed is a uniqueapproach for identifying and integrating key elements of a holistic RQT, which can be used to design an efficient test plan. This approach unites the reliability studies performed during development stages, and further, uses accelerated testing for successful product development, resulting in both cost and time-to-market improvements.

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