Subsea Hot Tapping For New Pipeline Tie-In

Hot Tapping is a technique which allows new fields to be tied-in into existing subsea pipelines while those pipelines remain under normal operating conditions. This allows development of marginal fields and efficient use of the existing infrastructure. Successful Tapping into a live pipeline revolves around specific project engineering, meticulous preparation as well as careful planning and onshore trials to ensure all risks are assessed and controlled. Sub sea tie in of pipelines is necessary due the never ending development of subsea fields and networks. In order to perform this work, it is sometimes necessary for pipelines to be shut down and flooded in order to make the connection. However, there is a technology that avoids this pipeline shutdown and allows execution of the tie-ins whilst maintaining the normal pipeline operating conditions. This technology is called Hot Tapping and has been widely used around the world for more than 50 years. Although the use sub sea in applications is not as frequent, nevertheless the inherent gains are just as important. Inspite of the fact that Hot Tapping is not a new technology, in 2008 a subsea operation was executed in the North sea that was a record breaking achievement due to the operating pressure of the pipe: 147 bar. A dedicated machine had to be designed and tested to the full pipeline design pressure which was 172 bar. This paper will describe the overall procedure that was carried out by the full time dedicated onshore team and offshore divers. Timing, results and benefits will also be evaluated and commented in this document