Session: 03-04-02 Inline Inspection Performance III

Paper Number: 134003

134003 - Using Eliminative Argumentation to Enhance Trust in ILI Results 

Abstract: 

Pipeline operators have traditionally relied on unity plots from integrity digs as a basis for trust in the results of Pipeline In-Line Inspection (ILI). They might also consider their confidence in the ILI tool vendor as a proxy for confidence in the ILI results. However, past digs provide a narrow view of ILI success, and operators have limited visibility into the equipment and processes used by vendors.

In this paper, we describe an analytical approach for enhancing trust in ILI results that borrows methods from safety assurance decision-making in the automotive, rail and nuclear power industries. Our approach calls for close collaboration between the pipeline operator and the tool vendor, and uses eliminative argumentation (EA) to create a reuseable assurance case framework. This framework is a logic tree that links a top-level claim about trust in the ILI results with evidence that is acquired and evaluated for each specific inspection. Part of the novelty of this approach is the use of EA to avoid the tendency, known as “confirmation bias”, to search for or recall information that supports a desired outcome, and to ignore information that disagrees with preconceived ideas. The assurance case created in this approach covers all activities performed during an inspection, from identifying required inspection performance, to equipment and processes used by the vendor.

Our preliminary experience with this approach demonstrated the benefits of involving the vendor directly in constructing the assurance argument. Visibility into the vendor’s safeguards provides an opportunity to establish a robust basis for trust that extends beyond unity plots from integrity digs.  The assurance case framework also references data called “indicators” as part of the supporting evidence. These indicators act as warning signs that adverse events might have occurred during the inspection and that an ILI run might require further examination to confirm the trustworthiness of the results. The structure of the assurance case clearly defines the causal connection or “golden thread” between the evidence (including indicators) and trust in the inspection. This traceability allows the operator to differentiate between minor deviations from the norm that do not impact the trustworthiness of the ILI results, and anomalous indicators that are of greater concern. This approach is generalizable, and a framework created for a given technology can be easily adapted for other technologies or enhanced when new information is available. Overall, this approach yields a more comprehensive, robust, and examinable basis to enhance trust in ILI results while reducing reliance on investigatory integrity digs.

Presenting Author: Vijay Nachiappan Enbridge

Presenting Author Biography: Vijay Nachiappann MSME, P.Eng is an Engineer with Enbridge in Edmonton, Alberta.

Authors:

Adam Casey Critical Systems Labs
Laure Millet Critical Systems Labs
Jeffrey Joyce Critical Systems Labs
Vijay Nachiappan Enbridge
Sean Keane Enbridge