Framework Design
Criteria definition, sub-criteria, scoring scales and weighting methodology agreed with the operator and, where appropriate, with the regulator before assessment begins.
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Comparative Assessment & Option Selection
A defensible, auditable route from a long list of decommissioning options to a single recommended option — with the reasoning visible to regulators and stakeholders.
Overview
Comparative assessment is the mechanism by which a decommissioning decision becomes defensible. It is also where most programmes are weakest: options scored against criteria nobody agreed in advance, weights chosen after the scores were known, and a recommendation that reads as a conclusion looking for a justification.
VORYX runs comparative assessment as a governed process. Criteria and weights are agreed and recorded before scoring. Evidence for each score is traceable to a study, a survey or a quantified estimate. Sensitivity analysis shows whether the recommendation actually depends on the weights — which is the first question any competent reviewer asks.
The framework applies wherever options must be compared: derogation cases under OSPAR Decision 98/3, deviation applications under the OPGGS Act, pipeline decommissioning options, drill cuttings piles, and reuse or repurposing decisions.
Scope of Work
Option Long-List & Screening
Systematic generation of credible options per asset group, with documented screening criteria and recorded reasons for every option removed.
Evidence Assembly
Each criterion supported by underlying work — engineering feasibility, environmental assessment, cost estimate, risk analysis — rather than expert opinion alone.
Scoring & Weighting Workshop
Facilitated multi-disciplinary workshop with structured scoring, recorded rationale per score, and dissent captured rather than averaged away.
Sensitivity & Robustness
Weight variation, score uncertainty and scenario testing to establish whether the ranking is stable — and to identify the specific assumption that would change the answer.
Justification Reporting
Regulatory justification report written for submission, with the full audit trail from long list to recommendation.
Methodology
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1
Agree the rules first
Criteria, sub-criteria, scoring scale and weighting method are fixed and documented before any option is scored. This single discipline is what separates a defensible assessment from an advocacy document.
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2
Build the option set
Generate a genuine long list per asset group — full removal, partial removal, leave in place with remediation, reuse or repurposing — and screen against feasibility with recorded reasoning.
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3
Populate with evidence
Pull scores from the technical, environmental, safety and cost work packages. Where evidence is thin, it is recorded as a data gap and carried into the uncertainty analysis rather than smoothed over.
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4
Score under facilitation
Independent facilitation, multi-disciplinary panel, rationale recorded against each score, and no scoring by the party that produced the evidence alone.
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5
Test the result
Run weight sensitivity and score uncertainty. If the preferred option only wins under one weighting set, that is the finding — and it is reported.
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6
Write it for the reviewer
Produce a justification report that a regulator, a stakeholder and an independent reviewer can follow end to end without needing a verbal briefing.
Deliverables
- Comparative assessment framework and criteria definition
- Option long-list and screening report
- Evidence matrix linking each score to source studies
- Facilitated scoring workshop pack and minutes
- Weighting rationale and stakeholder input record
- MCDA model with sensitivity and robustness analysis
- Option ranking and recommendation report
- Regulatory justification report (derogation / deviation support)
- Stakeholder-facing summary of the decision basis
- Audit trail package for third-party review
Standards & Codes
Work is delivered against the applicable international and regional framework. The codes below are those most commonly governing this scope — the controlling set is confirmed per project and jurisdiction.
- OSPAR Decision 98/3 Derogation assessment against five criteria
- OEUK Comparative Assessment Guidelines Industry-standard CA process for decommissioning programmes
- Petroleum Act 1998 UK pipeline and installation decommissioning
- OPGGS Act Australia — deviation from the full-removal base case
- London Protocol 2019 Revised Guidance for platforms at sea
- ISO 31000 Risk management principles
Frequently Asked
Who should set the weights?
Not the engineering team alone. Weighting reflects value judgements and should involve the operator's decision-makers and, where the process allows, stakeholder input. What matters is that weights are set and recorded before scores are known — and that sensitivity to them is reported.
What if the assessment does not support the option we expected?
Then that is the finding, and it is far better to discover it in a study than in a regulator's response letter. In practice the more common outcome is that the assessment confirms the direction but reshapes the scope — which is exactly what it is for.
Is comparative assessment only for derogation cases?
No. It is equally useful for pipeline decommissioning options, campaign strategy, reuse and repurposing decisions, and any situation where several defensible options exist and the choice must be documented.
Can you facilitate the workshop independently?
Yes — independent facilitation is often the most valuable part of the scope, particularly where the operator, the duty holder and the regulator each need confidence that the process was not steered.
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