Trenchless technologies are increasingly used to install pipelines at crossings with environmentally sensitive features, highways, etc. For deep crossings installed in rock via horizontal directional drilling (HDD), there has been concern within the pipeline industry about the effectiveness of conventional monitoring and cathodic protection techniques.
This paper summarizes the results of research sponsored by the Pipeline Research Council International. Field testing was conducted at a long crossing installed in rock where an array of monitoring and cathodic protection equipment had been installed, and recommendations were developed.
The testing indicated that deep sections of the pipeline in drilling mud required low currents to polarize. The installation of deep coupons in an environment similar to the pipeline’s is recommended. Only small differences were observed between the efficiency and effectiveness of local shallow and deep groundbeds.
