The need for accurate pipeline network charts m the Mahakam Delta (Indonesia) became imperative for safe and efficient operations. Due to the specific environment conventional pipeline survey methods could not be utilised. A novel deployment method needed to be developed to cope with the particular environmental constraints. An innovative two step survey methodology implementing seabed imagery and magnetism was developed and deployed to produce a comprehensive set of high accuracy as-built pipeline charts.
The objective of the survey was to obtain accurate x, y, z charts (+/-0.25m vertical & +/-0.5m horizontal) of the Company pipeline network in the Mahakam Delta (Eastern coast of Borneo - Indonesia). Having such charts is clearly essential for the safe operation of any pipeline system. This need is even greater in the Mahakam Delta due to the high number of 3rd party river users, the sensitive nature of the environment, the complex pipeline operational constraints, the rapid development and resulting construction activities and the massive production potential. In addition to the above, it was also essential to have accurate as-built pipelines charts before embarking on the planned extensive repair programme.
The Mahakam Delta is a giant oil an gas field of around 400 square kilometre where twenty-two major pipelines ranging m diameter from 16″ to 30″ transport fluids from the producing wells to process units and then to export facilities. All together pipeline network is 750 km.
Due to a combination of both process and environmental factors, the operation of this pipeline network is a major challenge. From a process side the wet gas contains between some C02 and Organic Acids making the complete network susceptible to Top of Line (TOL) Corrosion This phenomena only occurs however when the pipelines are subject to external cooling. Inspection by intelligent pigging has proven that lines that are adequately buried are not susceptible to TOL Corrosion
Environmental factors also pose a major operational challenge with the ever-changing Mahakam Detla The removal of vast areas of mangrove to make way for shrimp farms has destabilised the soil resulting m extensive erosion and pipeline exposure Where pipelines are exposed they are susceptible to mechanical damage and TOL Corrosion.(The Figure is available in full paper)
The complex geo-technical environment and the high pipeline operating temperatures have also created another operational challenge - Upheaval Buckles (UHB). A few UHB's occurred. They actually represent a risk as UHB's protruding from the seabed have no mechanical protection and are therefore susceptible to mechanical damage In addition they have no thermal protection which also makes them susceptible to TOL Corrosion.(The Figure is available in full paper) On the major crossings and on the major rivers further down the delta there are numerous areas of exposed pipelines at risk from, and presenting a risk to, the continuous bustle of river traffic. These exposures are caused by both natural erosion of the river bed and problematic burial.