As the focus of global oil exploration shifts toward new terrains, the demands on its equipment are increasing. And as the pace of exploration shows no sign of slowing, new extreme conditions are being encountered all the time, with deepwater, corrosive wells and arctic locations just some of the places where polymers are exposed and must survive in service, sometimes for decades.

To ensure that these challenges can be met, materials testing companies are required to be ever-more inventive and responsive in their testing. They must be able to push materials to their limits while maintaining quality assurance for customers to ensure that components used in situ are able to reliably withstand the most extreme temperatures and pressures.

HP/HT conditions (along with factors such as high levels of hydrogen sulfide [H2S], CO2, high stresses and hostile fluids) are some of the most significant challenges to the integrity of materials in oil and gas production environments. Component manufacturers are turning to HP/HT and related materials testing to meet the challenges they are facing.

Changing requirements

HP/HT testing is conducted to qualify materials for use in components for oil and gas production environments. A range of industry standards exists for the purposes of materials qualification, but manufacturers are increasingly demanding custom tests with an emphasis on more extreme environments so that long-term reliability can be determined.

Industry accreditations such as ISO 23936 play a role as an international standard. This standard is broader than NORSOK M710 and is used to test polymer sealing materials, rubbers, plastics and H2S, applications for both thermoplastics (part 1) and elastomers (part 2) with future parts for thermosets and composites. Such test standards will form part of a regular suite of tests and allow the rigorous testing of polymeric materials used for sealing, pressure barriers, hoses, flexible pipe and risers, or other purposes in components.

Many customers looking to qualify materials in more extreme oil and gas production environments increasingly need to exceed the parameters of the qualifications mentioned to represent actual service conditions and functional testing. Custom tests are therefore being carried out by a range of industry leaders such as Element Materials Technology to meet the new HP/HT testing demands.

Higher temperatures and pressures

In recent years there have been identifiable trends in the demand for scaled-up HP/HT materials testing, often called ultra- or extreme-HP/HT. HT materials testing was previously required for between 230 C to 240 C (446 F to 464 F); however, HT material testing is now being carried out at temperatures up to 315 C (599 F). Many polymers have defined thermal limits beyond which they will degrade or cease to deliver the polymeric properties for which they were chosen. This has encouraged material manufacturers to develop new compounds with higher limits, design engineers to reduce the impact of temperature on component function, and test experts to both better define the limits of current materials and explore the boundaries of new materials through innovative test methods and techniques.

A similar pattern can be seen in HP materials testing. While a base level of 5,000 psi is sufficient for many uses, tests are now conducted in ranges including 20,000 psi and even up to 35,000 psi.

The larger scale of testing demands has increased investment and expertise from those working in materials technology to ensure that testing quality is not compromised. Industry leaders such as Element Materials Technology are able to put their knowledge and skill sets to testing materials at the limits of that required by the E&P industry, relying on globally recognized experts and reputation for quality.

New advances in materials

Material innovations have opened up these new sites for exploration, with opportunity to explore new oil and gas production environments. This means new testing parameters have become necessary. These tests include low-temperature rubbers, new grades of thermoplastics able to withstand the aforementioned high temperatures and pressures and variations of new materials for critical sealing applications.

Expert HP/HT materials testing, therefore, not only relies on the ability to scale up existing tests. As the polymers themselves are adapted to new conditions, trusted testing partners are required to interpret the results from these data, allowing further materials development for still further hostile applications.

HP/HT laboratories

Sites such as Element’s Hitchin laboratory (formerly known as MERL Ltd.) have needed to develop capabilities to sustain clients.

Element Hitchin doubled its capacity in October 2014, allowing it to provide the NORSOK M710 and ISO 23936 qualifications on a greater scale as well as meeting the expectations of clients who wish to test at the unprecedented temperatures and pressures highlighted. This capability is being mirrored in the Element Houston facility.

Facilities such as Element Hitchin make use of an enormous range of technologies to deliver on the required materials tests, from a large number of custom vessels, which can be directed to a range of customers and requirements, to the agility to adapt and move vessels as necessary. This means that a great range of polymers can be qualified at the pressures and temperatures required. Facilities include the ability to monitor material performance after exposure to HP/HT fluids such as production gases and liquids, H2S, and chemical treatments; to examine materials in situ while they absorb fluids; and to measure leakage, permeation and function of seals, liners and barrier layers at HP/HT and model these components under extreme conditions using materials data generated in the test lab.

The Hitchin laboratory also implements industry-leading design, making use of remote monitoring and regulation of vessel temperature and pressure. The system also includes a CCTV feed to allow staff and clients to view the laboratories remotely. Data acquisition and reporting also must meet the highest standards to ensure efficient servicing of customers.

The future of HP/HT

As oil and gas production develops in a climate of increasingly complex environments, innovation will become crucial to extracting maximum value. Oil and gas production will continue to rely on the ability of materials technology testing to qualify both large ranges of materials able to withstand normal conditions and materials that can withstand the highest temperatures and pressures.

Strategy is crucial in such a fast-paced environment. Tests that serve a client’s needs today may be rendered irrelevant by advances in materials or testing techniques in a year’s time, so building good relationships with testing companies at the forefront of the industry will allow customers to continue to innovate.

Custom tests that allow them to qualify materials and components for bespoke use in unique locations will see the parameters for testing pushed to limits that are currently infeasible. Ultimately, as the landscape changes in production environments, it is crucial that HP/HT testing remains reliable and adaptable to the needs of customers.