Method aids execution, improves subsea equipment reliability

Nov. 26, 2007
Consistent practical methods for defining equipment qualification and testing requirements can improve subsea equipment reliability and facilitate project execution.

Consistent practical methods for defining equipment qualification and testing requirements can improve subsea equipment reliability and facilitate project execution.

ExxonMobil Development Co. (EMDC) has developed a systematic, structured approach to equipment qualification that uses failure-mode assessment (FMA) templates and product qualification sheets (PQS). The approach is based on existing industry methods that support equipment design reviews and provide for uniform information display.

To develop this subsea qualification process, the company identified and developed several principles based on lessons from recent deepwater projects, vendor input, and a review of previous standardization initiatives. By adopting this standard equipment qualification format, others in the deepwater industry can benefit by more efficiently managing operator and vendor interfaces, consistently highlighting critical design features, and taking advantage of previous component qualification programs.

This process also can facilitate execution efficiencies, reduce delivery schedules, and capture lessons learned.

Deepwater equipment

Deepwater subsea developments typically contain highly engineered equipment and involve numerous subsuppliers. These developments are often an industry step-out into deeper water and include first-time applications in which operators may expect equipment to work flawlessly for 20 or more years.

Additionally, subsea is still a continually maturing area and deepwater subsea developments remain a frontier that exposes operators to high costs due to unforeseen technical issues. The industry has experienced several subsea equipment failures for which root-cause assessments have indicated that the designs were not fully qualified, proven designs were modified, or subcomponents substituted.

Qualification based upon specific project service conditions is critical, and equipment assessments relative to these service conditions are essential to each project. Without a consistent industry qualification approach, operators may interpret differently what it means to have qualified or field-proven equipment.

EMDC’s subsea systems group is pursuing standard equipment qualification practices, tools, and documentation as a strategy for improving reliability in its future deepwater subsea projects.

Qualification complications

Because deepwater subsea developments are relatively new, companies seldom have well-defined qualification status of vendor equipment before awarding a contract and often address this on a project-by-project basis. They frequently determine design nuances and additional required qualification after the award of the contract. Without a well-defined qualification testing program, equipment reliability can be compromised.

To ensure qualified equipment, companies need to document the qualification process and allow this documentation to be available for operator review and acceptance.

Qualification requirements for many subsea components, however, are not specifically governed by industry standards because the standards do not consistently cover qualification of subsea components. When this occurs, this gap is bridged with operator specifications and engineering judgment. Because these are operator specific, the challenge is to gain alignment across the deepwater subsea industry on acceptable qualification-testing standards and methods.

Technical lessons learned regarding equipment design and performance are difficult to institutionalize without a formal process directly linking design with qualification and quality requirements. Companies should capture what industry has learned to avoid repeat failures and transfer industry experience to next generation resources.

The qualification process should consistently focus on critical design features, be failure-mode based, and capture industry experience and lessons learned, including new failure mechanisms.

Companies should also link qualification of a design to quality assurance and control of the product. Critical features may need potentially tighter acceptance testing based on operator service conditions.

A successful qualification approach must also establish a better mechanism to document and communicate functional requirements and potential failure mechanisms with vendors and their growing supply chain, particularly second and third-tier suppliers who may unknowingly provide critical subcomponents for subsea service.

In heated market conditions, qualification processes should accommodate the realities of supply-chain management and provide features to incorporate new suppliers efficiently. Additionally, “operator tinkering” needs to be rationalized because this may result in misalignment with vendors’ standard product lines, which may in turn lead to new qualification requirements and unforeseen risk due to manufacturing changes.

Qualification methods

Similar to industry job-safety analyses or hazard-identification programs, companies should actively pursue subsea equipment qualification and reliability. Rather than only focusing efforts on reactive numeric failure analysis, EMDC employs a qualification methodology objectively to evaluate the adequacy of the equipment qualification and quality programs.

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EMDC believes its qualification approach can be optimized by applying the following strategies (Fig. 1):

  • Focus the evaluation at the component level within the system hierarchy.
  • Reference vendor part numbers to lock down technical definition and associated manufacturing-quality processes.

This method allows operators to identify and track—in terms of technical definition, qualification, and quality assurance—a set number of common components that can be optimized in various system configurations across a number of projects.

Management at the component level also minimizes the cost of prestocking strategies (for both the vendor and operator) as client configuration preferences remain relatively low at this level. Local-content directives also may require assembling larger equipment packages in country. It also enables robust management of change and communication processes between the operator and vendor.

This approach has three key underlying processes that promote its success:

  1. Breaking down components into primary “building-blocks.”
  2. Implementing generic failure-mode assessment (FMA.)
  3. Implementing generic product qualification sheets (PQS).

Component-level breakdown is consistent with API categories. A comprehensive component-level breakdown can cater to wide flexibility for field-specific configurations. EMDC based the FMA approach on a simplified version of a failure-mode effects and criticality analysis, often used as a design tool within the industry. For example, this is recommended as a technology qualification tool in DNV-RP-A203.1

The FMA highlights component-specific failure mechanisms and critical design features. The PQS approach involves developing generic datasheets, similar to topsides-proven instrumentation, systems, and automation society (ISA) data sheet processes.

This part number-datasheet approach improves qualification because it supports a structured process that improves visibility of technical information and fits well with the vendors’ internal tracking systems. This approach enables improved management of detailed design changes, as well as facilitates procurement, contracting, and tracking of lessons learned.

Additionally, this process is applicable readily to proven field-tested components, increasing efficiency of the qualification process and reducing the need continually to redefine qualified or field-proven equipment.

Component breakdown

Because the focus of EMDC’s qualification approach is on the inherent value of the use of component-specific datasheets, an important first step of this process involves identifying components used in typical deepwater subsea development operations. Using API standards and experience, EMDC has identified 11 component categories and about 75 components based on functionality and classes of equipment.

The component categories include valves, hydraulic-chemical controls, electric controls, coatings, and insulation, while the components for valves include such types as ball, gate, and needle and for electric control of such equipment as flow meters and wet-mate connectors.

Once EMDC identifies and categorizes subsea components, the components are consistently documented in individual PQS.

Failure-mode assessment

The FMA process provides a systematic way to identify component failure modes and mechanisms and the tests needed to qualify a component relative to its intended function.

EMDC derived the basis for the FMA templates from DNV RP-A203, which applies specifically to components and equipment for offshore developments. The templates’ objective is to ensure systematically the technology functions reliably within specified limits. This aspect of the process is important particularly because it allows operators to identify failure risks and to test components and equipment before project execution.

The strength of the FMA process is that it allows operators to identify critical qualification tests and acceptance criteria that encompass testing of potential failure mechanisms. For example, EMDC completed an FMA on a thermoplastic hydraulic flying lead (HFL) component and identified 51 potential failure mechanisms (Table 1). A regrouping of the FMA data, however, identified only nine unique qualification tests for evaluating all potential failure mechanisms.

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Narrowing the qualification into these nine tests optimizes the time spent on the testing and analysis of the HFL.

The FMA process allows for increased visibility of failure modes and acceptance criteria, which in turn allows for improved qualification testing as full life-cycle requirements are better understood.

Product qualification sheets

EMDC uses the PQS based on ISA-TR20.00.01.2 Almost all oil and gas operators and vendors throughout the topsides industry use these ISA datasheets, originally published in 1956. ISA says the purpose of these standard forms is to:

  • Assist in preparation of a complete specification by listing and providing principal descriptive attributes.
  • Facilitate quoting, bid reviews, purchasing, receiving, inspection, design audit, accounting, and procurement by uniform display of information.
  • Improve efficiency of activities from initial concept to final commissioning and any subsequent review and revisions.

Operators incorporate new datasheets based on industry need. The basis of the EMDC subsea systems process is to establish a similar standard that aligns the operators and vendors for deepwater development projects, with additional emphasis on the uniform display of qualification information.

Currently, EMDC has identified 75 generic component datasheets specific to deepwater subsea development. It will also generate a unique PQS for each vendor of that component.

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The PQS (Fig. 2) helps achieve qualification, quality, and reliability objectives by providing a standardized way to present the following fives types of information:

  1. Component identification information, including:
    • Type of component or assembly and description.
    • Vendors and subsuppliers.
    • Part and bill of material (BOM) numbers.
    • Drawing number.
    • Assembly procedure number.
  2. Service conditions and operating parameters, including:
    • Water depth.
    • Operating pressures and temperatures.
    • Material class and requirements.
    • Design life.
  3. Preferred configurations and characteristics, including:
    • Operational equipment selection.
    • Location and orientation of elements.
    • Preferred coatings.
    • Labeling and markings.
  4. Qualification testing requirements, including:
    • Applicable industry standards and codes.
    • Acceptance requirements.
    • Performance verification information.
  5. Quality requirements and inspections, including:
    • Inspection and testing requirements, for example for a factory acceptance test (FAT) and a site integration test (SIT).
    • Dimensional verification requirements.
    • Documentation requirements.
    • Material identification and traceability.

Improved reliability

The process improves reliability by migrating toward standard documentation and components for which a company can establish continuous improvement programs. Poor equipment performances or field failures are often vendor specific and cannot be managed or enhanced in a generic database approach.

The performance-failure issue will likely have a root-cause associated with a component’s design, manufacture-assembly procedure, or quality assurance-quality control (QA-QC) programs. By referencing the vendor’s part number, the PQS provides a direct link back to specific vendors’ internal tracking systems and interfaces with manufacturing and quality systems.

The FMA templates used in this approach also facilitate permanent capture of design lessons learned associated with poor equipment performances or field failures.

Original qualification becomes highly leveraged as the deepwater subsea industry continues to evolve. Companies routinely optimize or improve subsea product lines based on development complexities, operating experience, and lessons learned. The detailed documentation supports a structured management-of-change program, ensuring increased reliability with modifications to proven designs.

Broadening the PQS approach on an industry basis will accelerate reliability improvement as a common communication mechanism will enable more effective documentation of field failures. Additionally, companies can use the qualification documentation as training and reference tool for less experienced personnel, as the captured lessons learned provide information to maximize efficiency, reliability, and resources.

Streamlined PQS

Streamlined PQS documentation facilitates successful project execution for both vendors and operators. Using PQS data sheets, vendors also can communicate to subsuppliers the detailed requirements for components and equipment and other critical information.

The PQS process has the potential to maximize vendor efficiencies and facilitate tendering, bid evaluation, and project execution for proven common components. With increased efficiency on managing vendor resources, a project team can focus more on project-specific issues, thereby reducing time spent during early project life on equipment qualification reviews.

Operators gain increased project oversight on purchasing, offering the potential to minimize engineering costs and reduce contingencies. As resources are constrained by short schedules, this standardized process allows vendors and operators to quickly access information and efficiently address issues, which increases the likelihood of delivering on time.

The standardized approach also provides higher visibility of qualification using clear documentation, which facilitates operators’ fit-for-service determinations. Additionally, it provides a structured starting point for management of design changes, upgrades to new service conditions, and qualification gaps.

Operators can also use the documentation created from this approach to help leverage qualification information across many projects. For adaptability to different field configurations, the component breakdown feature is ideal, particularly because it migrates toward using standard components throughout the deepwater subsea industry.

Local content

The systematic qualification process may also facilitate local content capabilities. The qualification process not only allows established vendors and suppliers to participate on proven goods, but also provides a better mechanism for adding new vendors and suppliers.

Companies also use the datasheets and assessments as training and reference tools to benefit local content by allowing local contributors to understand the requirements for successfully providing reliable components and equipment.

Dynamic framework

EMDC believes that this subsea qualification approach provides a reliability-enhancement framework that objectively evaluates vendor qualification programs.

EMDC offers its approach to equipment qualification for consideration as a new recommended practice for the rapidly evolving deepwater subsea industry; however, the principles, processes, and tools generated through this initiative also can apply broadly to other functional areas where equipment reliability is critical.


  1. Qualification Procedures for New Technology, Det Norske Veritas Recommended Practice. DNV-RP-A203, 2001.
  2. Specification Forms for Process Measurement and Control Instruments Part 1: General Considerations; Updated with 27 new specification forms in 2004-2006. Instrumentation, Systems, and Automation Society, ISA TR20.00.01, reprinted 2006.

The authors

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Chris Horan ([email protected]) is the subsea systems supervisor for ExxonMobil Development Co. During his 6 years in subsea, he has held various function and project roles. Horan holds BS degrees in mechanical engineering, biomedical engineering, and chemistry from Southern Methodist University and an MS in mechanical engineering from Texas A&M University. He is a member of SPE and ASME.

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Michael Starkey ([email protected]) is a subsea engineering advisor for ExxonMobil Development Co. and has 23 years of experience in subsea and completion engineering. In his present position he performs front-end engineering design for global subsea projects. Starkey has bachelor degrees in mining and petroleum engineering from the University of Strathclyde, Scotland.

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Dave Lucas ([email protected]) is the subsea systems manager for ExxonMobil Development Co. and has 30 years of experience with assignments in drilling, production, and reservoir. Lucas has a BS in chemical engineering from the University of Illinois and is a registered professional engineer in Louisiana.

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Steve Wheeler ([email protected]) is a subsea technical adviser for ExxonMobil Development Co. and has 30 years of experience in subsea related development work. He works within the subsea systems function supporting early project conceptualization activities and technology application assessments for subsea projects globally. Wheeler holds a BS in mechanical engineering from Texas A&M University.