In May 2015, a corroding California pipeline leaked over 3,400 barrels of oil into the Pacific coastline. This was one of several incidents that led to new regulatory scrutiny and growing operator interest on pipeline and asset integrity. The leaky pipeline was built in the late 1980s and entered service in 1991 making the pipeline only 24 years old when it failed. Integrity failure for an onshore pipeline at the relatively young age of 24 is concerning to many operators when over half of the 2.5 million miles of oil, gas, and other hazardous liquid pipelines in the United States are at least 50 years old.
Onshore pipelines are not the only assets that are facing problems. As offshore wells get deeper and are located in more hazardous locations monitoring and assuring their integrity becomes challenging. Pipe must be constructed with thicker walls in order to withstand higher pressures of deeper wells. Fields located in cold climates such as the Arctic, Alaska, and Nova Scotia come with their own unique challenges such as the threat of icebergs and the greater potential for plugging wax deposits. These challenges call for a greater focus on pipeline integrity. ADI Analytics has recently advised several operators and service providers on technologies and strategies to improve asset integrity.
There are three steps in addressing asset integrity. Addressing asset integrity has three main parts: prevention, detection, and repair. Improved operational practices and new technologies are being developed and implemented to address the prevention, detection, and repair of corrosion in assets along with other asset integrity programs. In this piece, we have looked at this issue using pipelines as a case study.
New materials and techniques are driving forward next generation corrosion prevention. New coating materials can be used to increase the lifespan of pipelines. Advanced and lightweight polymer aerogels can be applied to both the interior and exterior of pipelines to improve corrosion and compression resistance of steel lines, increasing the lifespan of lines and decreasing the chance of a pipeline failure.
Companies can also use existing pipeline coating materials in new ways. One of the most popular coatings for shallow water subsea pipelines is concrete. Concrete is effective at preventing corrosion but the cost of shipping a large and heavy concrete coated pipeline from the coating facility to a site offshore can be expensive. Shipping costs can be greatly reduced by bringing a concrete coating facility much closer to the offshore site. Companies can construct modular pipeline coating facilities near the installation site in order to reduce shipping costs.
Operators can choose from many pipeline integrity testing techniques and technologies. Being able to quickly inspect large lengths of pipeline is critical for operators who are looking to reduce risks associated with pipeline corrosion. We have extensively researched and sized the market for non-destructive pipeline testing in the past six months and have evaluated and profiled several proven and emerging technologies to inspect pipelines for corrosion.
“Pigging”, sending a small capsule or “pig” down a pipeline for inspection is one of the most common methods for large diameter pipelines. However, pigs cannot be sent down pipelines that are too narrow and the pipeline must also be shut down while the pig is in operation.
If an operator is looking to inspect a smaller diameter line or keep the pipeline operational during inspection some of the most popular technologies today are ultrasonic, digital radiography, pulsed eddy current, and CT scan testing. Each method has its benefits and drawbacks. These testing methods are used annually for high-risk pipelines to every five years for low-risk pipelines. Figure 1 shows a number of different inspection technologies and highlights some capabilities of each.
Figure 1: Select pipeline inspection technologies and capabilities
Operators also have the ability to constantly monitor pipeline corrosion using technology like constant ultrasonic, fiber optic, and corrosion probe monitoring. Service providers also offer pipeline leak detection and monitoring systems that constantly update operators on multiple metrics such as flow rates. This is an early entry into implementing data analytics and the Internet of Things to provide operators with more control over asset integrity.
New technologies are also helping improve the repair of compromised assets. Once corrosion has been detected, operators must repair the pipeline or risk a failure. While traditional repair methods still dominate the landscape smart pig technologies are emerging to address not only detection, as is traditionally done by pigs, but also to repair pipelines. For example, a pig has been introduced that has the ability to inject sealant during the inspection of a pipeline if leaks or corrosion have been detected. Although the new technology is more expensive than regular pigs that only handle inspection the cost is reportedly offset by eliminating the need to dig to fix a buried pipeline.
Pipeline corrosion poses a large problems for aging pipeline assets both on and offshore. Operators facing these challenges now have a growing number of technologies and techniques at their disposal.
-Tyler Wilson and Uday Turaga
