Element 10×Subsurface
Subsurface in Assurance
Assurance, Review and Improvement
What Subsurface owns here
This element holds independent challenge of subsurface — independent technical reviews, reserves audits, peer review processes and external expert reviews.
Example documents, by tier
Process, procedure, work instruction 4
- Subsurface Technical Assurance ProcedureIn 1 of 3 operator registersCompany-wideAlso in EI PSM · 20 Audit, assurance, management review and interventionNot process safetyNot safety case critical
- Subsurface Management of ChangeTypical exampleCompany-wideAlso in EI PSM · 12 Management of change and project managementNot process safetyNot safety case critical
- Subsurface Lessons Learned ProcessIn 2 of 3 operator registersCompany-wideAlso in EI PSM · 19 Incident reporting and investigationNot process safetyNot safety case critical
- Subsurface Evaluation ReportsIn 1 of 3 operator registersCompany-wideAlso in EI PSM · 20 Audit, assurance, management review and interventionNot process safetyNot safety case critical
Guidance · outside the system 1
Informative, not a “shall”. These belong in the knowledge base, not the management system. How this works →
- Oil and Gas Project Review GuidelineTypical exampleCompany-wideAlso in EI PSM · 12 Management of change and project managementNot process safetyNot safety case critical
Why these belong here
"Subsurface requires challenge, not just compliance."
What does not live here
- →The KPI data being reviewed — (Monitoring, Reporting and Learning)E09 Monitoring
- →The standards the review is testing against — (Policies and Standards)E02 Policies
- →The risk acceptance behind a decision — (Risk Assessment and Control)E05 Risk