by Cal Chapman
The Eagle Ford Shale development is causing a huge construction boom in infrastructure, pipelines, and plants. But it’s also causing big growth in water needs and power needs, and it’s introducing some interesting environmental and corrosion factors.
How do we measure growth? Well, we can certainly try and count the number of jobs available in a certain town, or county, and compare that with past years and decades. For each town and county, sales tax collections are tracked and compared. Recent studies show pretty clearly that sales tax revenues in counties affected by Eagle Ford growth are at least ten times greater than what was the case five years ago. As for employment, some estimate that 100,000 new jobs have come to South Texas thanks to the Eagle Ford Shale. These new people, new jobs, and new revenues also multiply the growth rate, with the need for more store clerks, schoolteachers, policemen, and so on. And that amazing growth strains the existing infrastructure, for sure.
So what is infrastructure? It is roads. It is power lines. It is water and wastewater systems. It is natural gas distribution piping in the towns, and propane gas systems in RV parks. It is cell phone towers and other radio and communication antennas. Some will even consider it to be school systems and local government functions like fire and police and courts and building inspection. We hope that the water and sewer utilities, the electric power generation and distribution companies, the state and county road authorities, and the telephone and data carriers are all focused closely on this growth, with good planning and budgeting and construction management.
Environmental issues that accompany growth can be as simple as, “Where do you find new water supply? Where does a community landfill its solid waste? Is the useful life of the landfill going to change with growing disposal needs? What happens with a wastewater treatment plant that’s now too small?” The good news is that expanding revenues for communities can help to tackle these kinds of issues. But what if new water supply is not readily obtainable? What if a city has to try and buy new land for solid waste disposal – for a new landfill? And then get the regulatory permit work done? These can be painful, expensive tasks to take on.
We also see a lot more corrosion and potential for corrosion troubles thanks to these expansions of infrastructure. As mentioned last month, a lot of South Texas soils will quickly damage exposed steel thanks to high salt contents and lots of clays. What does steel have to do with growth? Think of bridges for roads and railroads. Think of high-voltage power line towers. Think of the pipelines, not just for oil and gas, but for water. Yes, many of those water lines are now made of plastic. However, the valves, fittings, and lots of other parts are made of steel or ductile iron, of bronze or brass, or of other metal alloys. Every time a metal is used, it needs to be coated if it’s going into contact with soil or water. Even nightly dewfalls on bare metal above ground can cause substantial corrosion attack.
When two different metals are used, and they’re put into direct contact with each other, oops – that has just become a battery, discharging energy! We call this “dissimilar-metals corrosion,” and it can quickly turn a piece of steel pipe, which has been thread-connected, say, to a brass valve body, into a rusted, leaking mess! Whether the product inside is water, or wastewater, or oil and gas from production, this type of condition MUST be avoided! And yet we sometimes see otherwise knowledgeable “I&E” (instrumentation and electrical) technicians connect stainless-steel instrument tubing directly to carbon steel pipes. This is a no-no, guaranteed to cause the regular steel to corrode, especially if most of this equipment is buried in the soil. The same type of problem is often found in city natural gas distribution systems, when a technician inadvertently uses a brass fitting in what is otherwise an all-steel plumbing setup.
Yet another corrosion problem occurs when new steel pipe is added to an existing steel system. Unless cathodic protection and good coatings are put in place, the newer steel pipe – because it holds more energy in it than the existing steel – becomes an anode, and corrodes preferentially when it is “touched off to” the older steel pipe. Just that apparent little difference in “old pipe” to “new pipe” makes the same type of “dissimilar-metal” corrosion process occur.
Another thing to hone in on is this: when the small city or utility district, or electric cooperative, now growing like crazy, contracts to build an expansion of the water treatment plant, or to extend a wastewater or power line, we want to see good project design, followed by good construction and inspection practices, following by good ongoing maintenance and corrosion protection practices. That’s true for the school, the pipeline, the new water line, the new propane tank . . . you get the picture. It is our considered opinion that spending a little more money on this design and construction, and followed by a little more money on preventive maintenance over time, results in MUCH LONGER SYSTEM LIFE, and much less cost to operate, and maintain, and repair every system over its useful life. Oh, and let’s keep training in mind, too. The operators of all these systems need good training in their fields of expertise – another valuable investment!
There’s another type of corrosion problem, related to steel pipelines and high-voltage power lines that needs attention. As newer pipelines have been built, and been given really good-quality coatings, these pipelines can actually “generate” and hold electricity on them, thanks to high-voltage power lines being nearby. Referred to as “AC induction,” this phenomenon may create both a safety hazard and a potential for external corrosion on the pipelines.
We are very concerned about pipeline corrosion for yet another reason. If new structures are built, and coated, and then buried in the earth or put underwater, it’s not every part of the structure that comes under corrosion attack. It’s only the parts that got coated poorly, or where maybe the coating got scraped off as the pipeline was laid into the ditch. If we only expose a small part of the structure to Mother Nature’s attack, she gets to focus all the electrochemical reactions in that one local area. With a lot of metals, and steel is the most common one used for most of the infrastructure we’re talking about, this results in formation of a pit. And everyone can picture what a pit represents: an ever-deepening hole, maybe not that wide, but causing a wall to get thinner and hold less pressure, or a tank floor that ends up springing a leak. These things happen. And that’s why we stress the need for inspection during construction, for good coatings when they can be used, and for cathodic protection of those metal surfaces for the life of the system.
Cal Chapman is co-founder of Chapman Engineering, which began business in fall 1988. He is a licensed “Cathodic Protection Specialist” through the National Association of Corrosion Engineers (NACE, now called NACE International), and is a licensed professional engineer in Texas and New Mexico. Chapman Engineering provides cathodic protection, AC mitigation, coatings and corrosion protection specifications, and other engineering services. The company performs environmental compliance, assessment and remedy services in oilfield, petroleum wholesale, and industrial settings. In-house staff includes engineers, geologists, corrosion technicians and environmental scientists. Please contact Chapman Engineering at 800-375-7747.