innovation runs deep
Technology and innovation have long been a competitive advantage for Chevron. They play an important role in our business, helping us safely and cost-effectively unlock new opportunities – and are even more important in times of low commodity prices. Just take our operations in the North Sea, where we have a history of subsea technical innovation.
We discovered the Alder Field, located 100 miles (160 km) east of Scotland, more than 40 years ago. The Alder reservoir lies some 14,500 feet (2.75 miles/4.4 km) below the sea bed where pressures are 12,500 pounds per square inch – some 400 times that of a typical car tire – and temperatures hover around 300°F (150°C).
This type of high-pressure, high-temperature reservoir was considered impossible to develop until recent years. Today we have deployed an array of technological “firsts” for our company to overcome the challenges.
temperature and thermal management
In Alder’s challenging environment, innovation is helping us manage high temperatures to prevent hydrates and waxes from blocking flow and to limit stresses in the production pipeline. A special subsea cooling loop has been designed that reduces the intense temperature of production fluids before they enter the production pipeline – a technological first for Chevron’s global operations. We have also put in place a 17-mile (28-km) production pipeline with high-performance insulation between a 10-inch inner pipe and 16-inch outer pipe – known as pipe-in-pipe. The cooling loop/insulated pipeline combination means that Alder production fluids arrive at the platform ready for processing a full 122°F (50°C) cooler than in the well.
At Alder, a pressure management design typically used at the surface was applied subsea for the first time on a Chevron development. Called the subsea High Integrity Pressure Protection System, it manages the pressure difference between the reservoir and the receiving facilities.
pipeline condition monitoring
Alder’s carbon steel production pipeline is monitored continuously via a specially designed corrosion monitoring system that is fully integrated into the production pipeline. The system is called the Teledyne Cormon system and it captures real-time data and transmits it onshore for analysis and evaluation.
Pipeline condition monitoring is also supported by a subsea system that allows the integrity of the Alder production pipeline to be regularly examined. The system uses intelligent pigs – devices that are launched into a pipeline to measure its internal diameter and thickness. Pigs are sent from a temporary subsea launcher and recovered topside at the platform where condition data is downloaded and analyzed.
HPHT subsea tree system
Chevron also deployed a new subsea tree system at Alder called a vertical monobore tree. The system, which allows the Alder team to safely control production and manage any fluids injected into the well, is an advanced subsea technology designed to meet Alder’s high-pressure, high-temperature (HPHT) environment. We tapped our extensive HPHT expertise and combined it with lessons learned and best practices from HPHT fields across the industry before selecting the final tree design – a first for Chevron globally and a first for manufacturer OneSubsea.
Chevron’s technical experts have worked closely with Technip Umbilicals to design and manufacture the 17-mile (28-km) umbilical for Alder. The hybrid umbilical merges two technologies – steel tubing and thermoplastic hosing – to provide a more reliable and efficient subsea conduit to relay power, fluids and communications between the subsea equipment and the platform. The application of this technology is a first for Chevron in the North Sea.