When speculators first tapped the oil fields in Texas, they recounted stories of oil spewing from the ground like a geyser, allowing for the rapid development of this vast resource. The same was true in major oilfield operations around the world. Today, however, it’s clear the era of easy, cheap oil is over. In fact, the International Energy Agency estimates that more than 70% of our remaining oil reserves consist of heavy crude oil, often high in sulfur or CO2 content. The same is true of natural gas, of which more than 50% of the global supply is highly corrosive.
This paradigm shift in the oil and gas industry necessitates the availability of cost-efficient corrosion-resistant metals for E&P equipment. Unfortunately, existing materials are insufficient to withstand these extreme environments, leaving operators struggling to efficiently manage component degradation in the forms of corrosion and wear. Ultimately these challenges lead to increased operations and maintenance costs as well as more operational downtime.
To address oilfield component longevity and improve return on assets, oil and gas producers are quickly searching for alternative materials that can better withstand today’s more aggressive environments.
Exploring the options
Oilfield operators generally have two options when assessing materials. The first is to select a low-budget material with the understanding it cannot withstand highly corrosive environments and will thus require regular replacement. A frequently used option in this camp is hot-dip galvanized metals, which come in at a compelling price point but offer subpar performance. On the flip side, operators may opt for a higher performance material and the hefty price tag that comes along with it. Options here typically include tungsten carbide and diamond-like carbon materials.
Recently, a new choice has emerged in the form of nanolaminated materials, a new breed of metal designed to address this growing challenge. While the lamination technique can be found as far back as 2750 BC with the construction of the Tower of Gizeh, modern materials science has opened the door for new alloys with nano-scale layers, which allow precise control over the composite materials’ properties. Using commonly available raw materials, alloys with unprecedented levels of performance in corrosion resistance, strength, hardness, wear resistance and fracture toughness can now be constructed.
Building a new class of materials
The key to tapping the potential of nanolaminated materials lies in a novel production process. Traditionally, when developing alloys engineers can control just two of the primary factors impacting the performance of metals: alloy chemistry and alloy microstructure. Alloy chemistry encompasses the types of materials from which the metal is composed. Bronze, for example, offers the benefits associated with the properties of its primary components: copper, zinc and possibly tin. Another example is steel, which derives benefits from the properties of metals like iron and carbon. Alloy microstructure refers to the organization of an alloy. Microstructure is typically designed by heat-treating a metal or through mechanical working such as tempering to impact the crystallinity or grain size of the metal.
Modulation represents a third factor that can be uniquely controlled through the production of nanolaminated materials. Modulation essentially means piling nano-scale layers—between 10 and 100 nanometers in thickness—of homogenous alloys on top of one another to provide those materials with an interface. This unique layering process enables producers to optimize specific properties and build materials that are stronger, harder and otherwise more resistant to structural or mechanical failures.
To understand how this new class of alloys improves corrosion resistance and metal asset performance for oil and gas operators, it is important to first examine the corrosion process. Corrosion occurs when two metals or alloys come into contact, creating what is known as a galvanic couple. The coupling causes the alloys to exchange electrons, an interaction that generally results in one metal being protected at the expense of the other. Nanolaminated materials use the same raw materials found in conventional alloys, but by layering them at the nano-scale, producers can significantly delay the progress of corrosion or prevent the corrosion process from beginning.
In addition to their performance benefits, nanolaminated materials of this caliber also are revolutionizing metals engineering. Established production techniques use tremendous amounts of heat as the input form of energy. However, the use of heat does not allow for the control of metal formation on a small enough scale to effectively produce nanolayered structures. In contrast, the use of an electricity-based process can achieve this desired result. Furthermore, this electrometallurgical technique operates near room temperature, reducing costs and enabling efficient scalability.
Putting nanolaminated materials to the test
Nanolaminated materials have demonstrated exceptional performance in the field across a number of applications. In one example, a U.S. Department of Defense (DoD) customer operating in an aggressive marine environment found that even state-of-the-art corrosion-resistant coatings couldn’t prevent critical fastener components from deteriorating rapidly. After employing a cost-competitive nanolaminated alloy coating solution two years ago, corrosion in the operating environment has ceased. From an economic standpoint, the customer achieved a savings estimated at more than three times the value of the current component systems. When combined with the avoidance of potential asset failure, this estimate jumps to millions of dollars.
Considering the serious corrosion challenge the oil and gas industry is facing today, these nanolaminated alloy coatings have the potential to significantly impact the industry. As the U.S. DoD case study above illustrates, nanolaminated materials deliver unparalleled corrosion resistance, but they also offer performance advantages in addressing fatigue and wear.
Oil and gas assets will often exhibit cracking after heavy use. To combat this issue, nanolaminated materials possess crack-arresting characteristics at the interfaces of the layers. Additionally, the interface itself can serve to deflect, blunt or halt crack proliferation—up to 100 times improvement as compared to traditional alloy performance.
Leading oil and gas companies are deploying nanolaminated coatings in topside field trials on rigs around the world. One early adopter estimated the longevity and performance improvements enabled by nanolaminated alloys could save more than $250 million throughout the life of the field. The improved performance also will lead to more operational uptime and, thus, higher oil production rates over the lifetime of the field.
Nanolaminated alloys have the capacity to cost-competitively address the problems of corrosion, fatigue and wear for the oil and gas industry, providing oil producers with a unique approach to curb rising costs associated with harsh production environments. Modumetal Inc. is helping to lead this charge, working alongside industry leaders such as ConocoPhillips and Chevron to deploy these next-generation metals to the field.