Latest innovations in pipeline design
By Carl Wordsworth, Senior Consultant, BHR Group
The oil and gas market is volatile. Prices are receding again despite a recent stabilisation and the future market price prediction is not hopeful. According to the International Energy Agency, oil prices may fall further with the drop likely to last well into 2016. Simultaneously, easily accessible supplies are depleted or dwindling. To counter these challenges, oil and gas companies are seeking to increase their oil production from hard to reach places, such as deepwater locations, sited far offshore. But this approach brings considerable physical challenges e.g. extremes of pressure and temperature for the materials and methods used in extracting and transporting the oil.
Forward looking oil and gas companies are reshaping their approach to production and extraction in order to create operational efficiencies in the long term. Many are turning to an open innovation model, partnering with other experts in the industry to provide solutions to the intricate and complex technical barriers to deep sea extraction.
Dwindling oil supplies are driving deep sea extraction and operational efficiencies
At first glance, global supply of oil seemed to rise during 2005-14. However, Mark C. Lewis, senior energy and sustainability analyst at Kepler Cheuvreux, remarks that this is only due to the impact of rising production from US shale oil. In fact, if shale oil supply figures were stripped out, global crude oil supplies actually declined. As a result, production from the hard to reach places, such as deep-water, is predicted to become the norm. Deep-water global capital expenditure (Capex) is expected to increase by 130%, compared to the preceding five-year period, totalling US$260 billion from 2014 to 2018, according to Douglas-Westwood's (DW) 12th edition of its World Deepwater Market Forecast 2014-2018.
Simultaneously, those who are already practicing deepwater activity will start to explore extraction in more extreme water depth. Current depths range from 1000 to 1500 m resulting in an external water pressure on the pipeline of around 150 bar. In the next 5-10 years as these water depths increase to 3-4000 m, external water pressures of up to 400 bar can be expected.
Challenges abound when extracting oil subsea, and the deeper companies go, the greater these challenges become. Materials and fluids used for sealants, insulation and the oil itself need to be protected when exposed to arduous operating conditions or else mechanical performance will be impacted, leading to operational cost increases.
These challenges are further aggravated by seabed temperatures and distant process facilities. Average seabed temperatures are typically 2-3 ° C while the fluids in the pipeline are likely to be hot. Unless the temperature for all fluids in the pipelines can be maintained, there is a risk of wax deposition and hydrate formation, resulting in pipe clogging and reduced flow Left unchecked, these could grow sufficiently to plug the pipeline completely with potentially catastrophic consequences. And, with the industry increasingly moving to more hostile environments where detection of stoppage points and accessibility are difficult, understanding the flow properties of materials being transported and the operational consequences of potential problems is paramount. Pipeline technology, materials and fluids have to change to ensure they can meet the requirements of their new environments.
Open innovation and industry collaboration: bringing in the experts
In order to evolve the technology and materials to support unique requirements for subsea projects, businesses are looking to industry experts and partners, especially when in-house teams do not have the time or expertise to do this. Unique challenges that may not be possible to solve in-house include overcoming differing compatibility details for materials across geographies, addressing changing pressures and temperatures in drilling environments, advising on the use of new technologies, and requirements for health and safety standards. In addition, external partners often have specialised, large and costly equipment with which to test and validate the performance of fluids and materials which would not be a cost-effective to deploy in-house.By using partners who commonly solve unique challenges through multi-disciplinary teams of mathematicians, scientists, design and computer modellers, costs are reduced through technology transfer – the application of learning from a previous project and transferring it to another. Open innovation experts can also help companies to create a strategic long term plan for the implementation of pipeline materials and fluids.
What partners can do
In the past, open innovation has helped oil and gas companies to understand which stress and strains on materials and fluid cause the formation of wax and hydrates in the pipeline and how to prevent this using the right type of pipeline insulation according to differing and new temperatures, pressures and industry standards.
Typically pipeline insulation, placed around the pipe and fittings, can be made from a variety of materials including polyurethane designed to maintain the fluid temperature inside for a sufficiently long enough time to avoid wax or hydrate formation. But these materials need to be impact, thermal-shock and simulated service tested according to different depth and pressure and temperature requirements.
And, also industry requirements need to be met. Recently a new standard from the International Organisation for Standardisation (ISO) – number 12736: 2014 - has been developed specifically to define the minimum requirements for qualification, application, testing, handling, storage and transportation of new and existing wet thermal insulation systems for pipelines, flow lines, equipment and subsea structures in the petroleum and natural gas industries. The purpose of these systems is to provide external corrosion protection and thermal insulation. Part of meeting the ISO requirements is a number of recommended validation tests for new insulation materials to make sure they are fit for purpose. These tests include those for pipe vending, impact, thermal shock and simulated service.
The right industry partners are well positioned to deal with both current and future testing demands to support standards. Not only do they have the expertise and resource to do this but they also have the technology and equipment, which, in the case of deep sea cool down and high pressure testing can often mean large and costly simulated service vessels (SSVs) or hyperbaric vessels.
Common tests required and performed by partners can be broken down into two areas including cool down testing and high pressure testing.
- Cool down testing, thermal properties: Tests the thermal properties of the material by heating the internal pipe, taking its temperature before placing it in a cold water bath to determine how long it takes the internal pipe contents to cool down to the temperature of the water. This reveals how long the insulation will keep the set temperature of the fluid in the pipeline, how quickly the temperature decreases and how long companies have before problematical waxes and hydrates form.
- Cool down testing, calculating the pipeline insulation heat transfer coefficient (the U value): This calculation is made to help determine how long a particular insulation will keep the pipeline at that temperature for. This is done by maintaining the temperature within the pipe, monitoring and measuring the amount of energy imported into it to keep it at a temperature allowing the calculation of the U value.
- High pressure testing, simulated service testing: This testing is done to simulate the long-term performance of an insulation system. Simulated service testing is specifically needed when a thermally insulated pipe or other subsea component, such as a valve, or instrument is exposed to the water pressure and temperature it will see in deep-water service. Usually this is done by placing an internally heated pipe in a pressure vessel. The internal pressure within the pressure vessel is then increased to represent the water depth the pipeline or component will be subject to in the subsea environment. By consistently measuring the temperature of the system as it cools the thermal properties of insulation are tested. The mechanical strength of the component being tested is measured by looking at the changes in the dimensions of the insulation material which surround the component over time. Typically these tests can last for several months with the component being tested being subject to the high external pressures for the complete period of the test. Ensuring the devil in the detail is found and addressed both now and in the future
When it comes to ensuring the best long term strategy for materials and fluids for deep sea operations, an innovative and collaborative approach is often the best. The ability to find the right mix of expertise within a business to test, validate and come up with new solutions to intricate and complex problems in a cost effective way can be difficult. With the ability to cleverly apply technology transfer to new situations within a niche field, partners can ensure that the devil in the detail is found so that requirements are met now and in the future.
Adapted by Louise Mulhall