The paper identifies data requirements and outlines a methodology for development of a robust assessment to support analysis of environmental, socio-economic, safety and engineering risks associated with onshore operational oilfield assets. The approach utilizes spatial analysis to rapidly characterize high consequence areas associated with pipelines, operational wells and storage infrastructure. It aids understanding of the extent and timing of hydrocarbon releases thus supporting response planning, prioritization of asset improvements and ultimately minimizing potential impacts.
The approach to risk assessment uses stages of analysis to screen out assets based on their setting and release scenario to enable greater focus to be applied to the highest risk areas. Working from initial regional baseline data, pipelines and other operational assets can be segmented into areas with similar risk profiles with subsequent numerical analysis being commensurate with the level of risk in each area. Identification of high risk areas enables prioritization of subsequent data collection and analysis of which source-pathway-receptor pollutant linkages require the greatest level of assessment to most accurately analyze the overall level of potential risk.
The detailed analysis may involve a range of transport modeling that could include overland flow, ground penetration, subsurface migration, surface water transport and air emission assessments. This paper focuses on the use of GIS based tools to analyze overland flow risks from surface or near-surface releases. To complement the analysis a range of sensitivity mapping tools/approaches are used to generate risk heat maps to clearly illustrate the most significant effects associated with the releases being considered.
This approach has been successfully undertaken in a wide range of geographies and for a range of purposes to assess the extent to which released products from planned or existing wells, pipelines, storage tanks, process plants and storage pits migrate over & beneath the ground. This has allowed operators to:
Establish the critical timing of impacts on high consequence areas (HCAs) – e.g. populations, rivers, etc.;
Inform site layout design (e.g. bunding height / location, positioning of emergency response equipment etc.);
Assess mitigation options & prepare emergency response plans; and
Iteratively assess consequence of engineering revisions and/or effects resulting from mitigation implementation.
The benefits of undertaking an assessment of this nature include reduced risk, enhanced reputation, lower financial exposure and provide a more robust evaluation to support financing. In some cases the assessment could reduce capital costs for unnecessary mitigation measures.