The recent development of X120 (Grade 825) high strength steel linepipe enables gas producers to realize significant savings in the total cost of long-distance gas transmission pipelines, lowering the cost of supplying gas to market. These savings can be achieved from cost reductions in multiple areas including material, construction, compression, and integrated project operations. This paper describes methods of achieving these savings and presents example pipeline project scenarios where application of X120 linepipe in higher pressure, smaller diameter pipelines results in total project cost savings of 5 - 15%.
In the early 1990's ExxonMobil identified transportation cost as a key factor in the commercialization of remote gas resources and research began on a project to reduce the cost of gas transmission pipelines through the use of linepipe manufactured from lower cost, higher strength steel. The concept was that additional commercialization opportunities would become economic by fully capturing the benefits of high-pressure transmission for large volumes of gas. The resulting impact of having this capability would be to expand the economic reach of gas pipelines thus enabling transportation from remote resources to market centers. The evaluation of how to most economically transport gas from remote sources of supply is a critical consideration in today's social and economic environment. The higher strength steel described in this paper provides an opportunity to not only reduce pipeline transportation costs, but in many cases may enable development of remote resources currently not commercial using existing technology. Realizing these benefits presented many challenges. The high strength steel development work at ExxonMobil, in conjunction with Nippon Steel Corporation and Sumitomo Metal Industries, has resulted in steel pipe with a nominal yield strength of 120ksi (825MPa) and the potential to reduce the total project cost of long distance pipelines on the order of 5 - 15%.