A Staged Approach for Managing Terrain and Geohazards on New Pipeline Projects

Abstract

Pipeline route selection and design is an iterative process by which one or more potential pipeline corridors are systematically narrowed from the general path of about 10 km in width to a highly specified 30 m to 50 m wide corridor. The process usually spans several years, and is frequently becoming increasingly complicated, requiring a multi-disciplinary technical and managerial approach that considers the political and regulatory process, environmental impact and permitting, project and industry economics, access, constructability, land acquisition, and terrain. Specialist technical contributions to the pipeline routing process include pipeline hydraulics, pipeline and facility construction, terrain/geohazards, and environment/archaeology. Problematic terrain and geohazards are two of several issues that need to be managed through the feasibility and design of a new pipeline project. As the project advances through Front End Engineering and Design (FEED) from feasibility to final engineering design and as the corridor narrows from kilometers to tens of meters in width, the level of detail required in ongoing terrain and geohazard investigations should increase to optimize the design process and match the increased detail being provided by other specialists. An idealized Four-Stage framework for managing geohazards and problematic terrain during pipeline routing and design is outlined in the paper. This framework has been founded on several international resources listed in the references and has, by necessity, been developed, tested, and refined by the authors over the last ten years on several large and small diameter pipeline projects in North and South America. Each of the 4 Stages is described and contains guidelines on project study scale, a target corridor width, the engineering design level, cost accuracy, and geohazard related engineering tasks and deliverables. This staged approach is provided as a road map to help guide all project participants including owners, project managers, engineers, scientists, and regulators to understand how geohazards and problematic terrain are managed through the pipeline routing and design process.