Geohazard Assessment of a Major Crude Oil Pipeline System - the Turkish Section of the BTC Pipeline Route

This chapter on the geohazard assessment of a major crude oil pipeline system is from the proceedings of an international conference on the terrain and geohazard challenges facing onshore oil and gas pipelines (June 2004, London, United Kingdom). The authors use the Turkish section of the Baku-Tbilisi-Ceyhan (BTC) Crude Oil Pipeline as a case example. The length of the Turkish section is approximately 1,100 km (in an overall system of 1,800 km) and the pipe diameter varies from 34 inches to 46 inches. This chapter outlines the way in which the detailed geohazard assessment was undertaken, involving a combination of geohazard review by the W.S. Atkins Consultants team, subsequent field investigations undertaken by ILF Consulting Engineers and their Turkish partners, and periodic audit review by an external team of specialists, appointed by BOTAS, the Turkish turnkey contractor. The authors describe the geohazards evaluated during the basic engineering stage, including landslide, fault rupture, liquefaction, and karstic collapse (solution of limestone and gypsum bedrock). In addition, a geohazard assessment was conducted for four pump stations and a pressure control station; three of these locations were subsequently relocated because of geomorphological or technical constraints. The authors conclude that, as a result of this phased investigative approach, the Turkish section of the BTC pipeline route constitutes an optimized and safe route, with minimal residual risk associated with landslides and erosion processes, seismic hazards, liquefaction, and karst areas.