Applications and Performance of Trenching Technologies in Asia-Pacific

Abstract

Description ofproposed paper: Burial ofsubmarine pipelines and cables is standard practice in offshore oil and gas regionswhere potentially damaging threats such as interaction with fishing gear anddragged anchors are high. The requirement to bury pipelines in Asia-Pacific hasnot had the same imperative as the North Sea for example but this region is nowseeing a growing demand for pipeline burial to increase mechanical protectionand stability. Performance benchmarks for most trenching systems are based onthe seabed soils typically found in the North Sea and consequently do notinclude the unusual carbonate rich seabed sediments that are prevalent in theAsia-Pacific region which are often cemented and pose a significant challenge to trenching. Application: Trenching isconsidered an activity with significant risk so it is particularly important toselect the correct tool for the field conditions and to establish realisticperformance criteria based on regional experience in the prevailing seabedsoils, including carbonate rich sediments. This paper addressesthe primary differences that exist in seabed sediments and trenching conditionsbetween Asia-Pacific and other regions and show how these dissimilaritiesimpact on the choice of burial equipmentand tool performance. Results, Observations, and Conclusions:A state of theart review of trenching methods and technologies is presented. Trenching casestudies from Australia and Asia are presented which highlight the challenges ofdesigning an appropriate protection and burial strategy for this region and providesindications of actual performance that can be expected across the range ofseabed conditions typically found in the Asia-Pacific region. This includesdata for trenching in harder cemented soils to help fill the gaps associatedwith performance predictions in carbonate sediments. Significance of Subject Matter: The significanceof this proposal paper can be summarised as follows:It provide a reference point onwhich to plan trenching work in Asia-Pacific region,It addresses the knowledge gapsassociated with the relative inexperience of trenching in Asia-Pacific regionPerformance benchmarking is extendedto include the carbonate rich and cemented sediments.