Fellow’s Corner

The latest article from ICorr Fellows who have made a significant contribution in the field of corrosion control is by Dr Sadegh Parvisi, Senior Principal Materials Engineer, McDermott, who describes the role of a Corrosion, Materials and Metallurgy Engineer. With some decades of professional engineering experience in engineering companies, operations and R&D, the author now shares this experience with fellow workers in ICorr.

The role of the Corrosion, Materials and Metallurgy Engineer in the integrity of Oil and Gas projects

This brief article is intended to highlight some strategic ideas to enhance the interaction of the Corrosion, Materials and Metallurgical (CMM) discipline with other fields, to improve the integrity of a project and enhance the reliability of the plants. It also aims to show the workflow, and identify the mechanism of interaction between all the disciplines engaged in the execution of a project.

Why CMM ?
Today’s corrosion engineers cannot produce meaningful and reliable outputs without having a proper relevant knowledge of Materials and Metallurgy. For instance, for a corrosion engineer it is not sufficient to only know the electrochemical processes well, but it would also be necessary for him/her to have a clear idea of the difference between PVC and CPVC. The CMM engineer should also understand, for example, the role of molybdenum on pitting and crevice corrosion of stainless steels, and to assess that even if this is not an issue, it is still vital to be aware of the huge cost impact of selecting between SS304 and SS316 steels in a LNG project. Hence this being considered as a single discipline which is named CMM.

Why is this subject important?
Consistency between the engineering project specification documents has a significant effect in the integrity of a project. This consistency cannot be achieved unless a dynamic interaction is built between the engineering disciplines. Quite often, it has been experienced that the final version 
of the Piping and Instrumentation Diagram (P&ID) is not compatible with the material selection specification or report. Piping classes specifying the material of construction’s corrosion allowance divert from the 
as-built P&IDs etc. The root cause of these discrepancies lies in the lack of 
proper communication between relevant engineers, in particular in the CMM discipline.

Phases of Project
Any project can go through different phases before it reaches a ‘live’ production. For example:

  • Conceptual
    FEED
    Detailed Engineering
    Procurement
    Fabrication & Inspection
    Installation
    Pre-commissioning
    Commissioning
    Trial Period
    Operation
    Maintenance
    Mothballing
    Extension/Revamping
    Conceptual
    Front End Engineering Design (FEED)
    Detailed Engineering
    Procurement
    Fabrication & Inspection
    Installation
    Pre-commissioning
    Commissioning
    Trial Period
    Operation
    Maintenance
    Mothballing
    Extension/Revamping

This article intends to briefly address some of the key activities in each phase.

Conceptual Phase
The most fundamental phase in which preliminary materials selection and 
 corrosion control, based on Statement of Requirement (SOR), and in line 
 with process design parameters, are made.

  • Innovation, discussion meetings with reputed vendors
    Risk of employing new technologies should not be ignored
    Optimisation and cost savings to be looked at carefully
    Discussion and agreement with the client on any software to be utilised 
 before it gets too late
    Site visit by CMM engineer can be very useful, if not crucial

FEED Phase

  • The project statement of requirements should detail scope of work for 
 this discipline
    Optimisation process, i.e. risk analysis and economic analysis should 
 be conducted

 

Detailed Engineering comprises

  • FEED endorsement
    Endorsement correction, HAZOP, licensor, etc. Corrosion control check-
 ups, Approved changes
    Full definition of materials (e.g. exact grade of titanium, etc., for example)
    Basis of material selection to be consistent with FEED
    Materials requisition and any technical deviation
    Critical review of package material, request for compliance
    Setting and finalising materials selection, as built
    Material selection control manual

 

Procurement and Construction

  • CMM to ensure compliance to specifications, and ensure that an exotic 
 material choice is not necessarily fit for service.
    Vendors technical bid and Concession Request (CR) document
    Upgrade requests from vendor should be assessed carefully
    Participate in pre-production meeting
    Materials selection change request during construction on CP, painting, 
 storage, etc.
    Issuing close-out report for as built condition
    No compromise to be made if it could affect integrity

Typical workflow for issuing a corrosion control material selection table/report.

Table of typical workflow for issuing a corrosion control material selection table/report.

Pre-commissioning

The CMM engineers to be alert to some of the procedures in the manual, such as hydro testing, and that they are practiced carefully.

The Interaction mechanisms

The simple diagram shows the relationship between the CMM engineer and the other disciplines, and the table summarises the links between a process engineer and a piping engineer, as the main disciplines interacting with the CMM engineer in any oil and gas project, in order to have a robust and solid material selection philosophy. Similar tables can be produced to include other disciplines’ scope of activities, for instance in applying a corrosion mitigation technique by ICCP, the interaction between CMM, pipeline, civil and electrical engineers should be clearly defined.

Summary

It is important to note that a continuous and integrated input and engagement of the CMM engineer is vital throughout all stages of a project, since the integrity, reliability and safety of the plant depends significantly on the degradation mechanisms and materials selection strategy – the backbone of a CMM engineer’s expertise.
The Oil & Gas company should ensure active participation of the CMM engineer and appropriate interaction of them with other disciplines throughout the project.

It is recommended that

  • The engineering director/company should ensure that there is a 
 continuous active participation, and appropriate interaction, of the 
 CMM engineer with other disciplines. It is also important that a proper 
 organisational chart is developed before the start of the project, and 
 the position and the work scope of the CMM engineer is defined for the 
 project, without any budget constraints for this important discipline.
    The harmful misconceptions that “Nothing Can Be Done About 
 Corrosion!” are avoided
    There is increased awareness of the large cost of corrosion and potential 
 savings that can be made
    A sound Corrosion Management strategy should be set-up by changing 
 policies, regulations, standards, management practices and attitudes, to 
 increase corrosion mitigation savings
    The education and training of staff in recognition of corrosion control 
 should be improved

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