Field-Tested Solutions Using Lay Flat Hose
The need to transfer produced and flowback water through lay flat hose for treatment, reuse or disposal is increasing. Traditionally, produced water and flowback have been transported by truck or HDPE pipe to a water-disposal or treatment facility. However, the cost and undesirable truck traffic have caused many companies to look for ways to transfer this water through lay flat hose in a similar manner as used in the supply of fresh water for a frack project. Also, fresh water is going up in cost and becoming harder to find, which has many companies working to find inexpensive ways to transport and treat produced water for reuse in another frack job.
Companies have been cautious to use lay flat hose because they are concerned that if something goes wrong, they could end up with a produced-water spill that could be very costly in fines and cleanup. Since each well produces its own unique blend of chemicals and temperatures, the materials have to withstand a wide variety of chemicals, concentrations and temperatures.
The problem with transferring produced water through lay flat hose made for fresh water is that some chemicals are corrosive to the thermoplastic polyurethane (TPU) hose, as well as the fittings, and other equipment that is commonly used for freshwater transfers. Also, high-temperature water can weaken and deteriorate the hose’s TPU liner. After inspecting many sections of TPU lay flat hose that have been used with produced water, what is often found is that the hose appears to be fine from the outside and the hose is not leaking. When the inside of the hose is inspected, it is seen that the chemicals and/or high-temperature water have caused some corrosion and/or deterioration. This usually starts to affect the hose at the folds, where there is more stress on the TPU material.
If the exposure to chemicals is long enough, then there is a good chance that the chemicals will eat through the hose and spill out onto the ground. When there are high enough concentrations of some chemicals, they can eat a hole through the hose in a matter of just a few hours.
One example is a project in Texas that needed to transfer produced water seven miles. The company used high-quality thermoplastic polyurethane lay flat hose, but the produced water quickly ate through the hose and created a costly and challenging cleanup. It also left the company with seven miles of unusable hose. The chemicals started eating through the hose along its folds and made a straight line of blisters and leaks as shown in Photo 2.
A few years ago, several operators and water-transfer companies in Texas independently approached Hammerhead Industrial Hose to see if there were any options for lay flat hose that were able to withstand the wide variety of chemicals and temperatures in produced water. These companies wanted to use lay flat hose with confidence that they would not end up with a costly produced-water spill. Hammerhead has always been at the leading edge of developing solutions to make water transfers using lay flat hose more safe, efficient and environmentally friendly. So, this was an interesting challenge. A joint effort was started with hose manufacturers and material suppliers to come up with a lay flat hose that holds up well to the range of chemicals and temperatures found in produced water. The results from this effort have been positive and proven that produced water can be transferred using the right lay flat hose with high degree of dependability and safety, making it a viable, cost-effective solution.
It wasn’t long after resolving which lay flat hose to use that other challenges were discovered. After transferring produced water for a while, the lay flat hose was doing well, but the various fittings started to exhibit chemical corroion. Photo 3 shows a standard aluminum coupler after 30 days of transferring produced water.
Hammerhead worked with an operator in Texas to test many different metals and coatings, and came up with several options that work well with a variety of chemicals and concentrations. Not surprising, it was found that for ultimate protection, you want couplers made of stainless steel. Due to the cost of stainless steel, it was important to continue searching for a lower-cost solution that holds up well to the chemicals. A good one was identified that consists of carbon steel or aluminum with a specific powder coating that holds up very well to chemicals. Because carbon steel is more durable than aluminum, the preference became couplers made of carbon steel with the chemical-resistant powder coating.
The couplers themselves also need to be made in a way that has good retention at high pressures and protects the hose without damaging it or producing leaks. Over the years, operators and water-transfer companies have learned there is a wide range of problems caused by poorly designed couplers. The best solution is a coupler that has smooth surfaces and as much surface area as possible connecting the hose and coupler. It is also important to have outer segments that support the hose securely with minimal gaps that could leak. Most companies that are successfully transferring produced water with lay flat hose have chosen a specific coupler that is proven to hold and protect the hose very well and is made of either stainless steel or carbon steel with the chemical-resistant powder coating. (See Photos 4 and 5.)
After a transfer of produced water is finished, it is important to remove as much of the fluid as possible. Working with water-transfer companies in cold winter climates, where it is critical to pig a line quickly in the winter, a pigging system was developed that quickly and efficiently evacuates the transfer line.
To resist chemicals and rust, it is good to either hot-dip galvanize or apply the chemical-resistant powder coating to the pigging system’s components. It was found that traditional pigs did not evacuate the line of fluids as well as was desired. So, another effort was undertaken to find the right type of pig that could swab out the inside of the line most effectively to reduce the chance that any fluid would be left in the line that could leak when retrieving the hose. After testing different materials and ideas, a “SuperSwab” was developed, which has a firm inner core that doesn’t allow the SuperSwab to “tumble” inside the hose. It is oversized and has soft foam on the outside to maintain good contact with the inner walls of the hose and fittings for maximum fluid evacuation.
Through these joint efforts and much field testing of produced-water transfers with operators and water-transfer companies, Hammerhead came up with the FracGard series of lay flat hose, fittings and other equipment that have proven effective in the field. Several companies have been working with the FracGard series of products for many produced-water transfers over the past couple of years with good results and no reported spills from equipment failure.
Many chemical plants and refineries have now standardized on FracGard hose because it resists corrosive chemicals and high temperatures, as well as adhering to self-imposed high standards that minimize hose elongation, expansion, delamination and unsafe bursts.
Of course, one of the most important factors to a successful produced-water transfer is a well-trained team that knows how to do things the right way the first time and to work efficiently and safely. It is also important to have a team that is experienced enough to get things under control quickly if something does go wrong.
Providing solutions that will work well in states that have environmental regulations so strict that operators are hesitant to take any risks of spilling produced water is a challenge that needs to be resolved. There is an attempt, working with several companies in environmentally strict states, to come up with a solution that operators and regulators will feel confident in. The ideal is to make sure that produced water is contained if the lay flat hose does leak. It is also important that the water-transfer company is immediately made aware of the leak and location so they can quickly correct the problem before it causes a spill that becomes costly to clean up.
Hammerhead has a solution that provides a double layer of protection with leak-detection capability. If the lay flat hose carrying produced water leaks, it will be contained within a second layer of hose, and the detection system can send out notification that there is a leak and where it is located. This should allow for resolution of the issue before any of the water spills out onto the ground.
The cost of a double-layered hose with the monitoring equipment will obviously be higher than the single-layer hose solution. But early indications show that it will be less expensive and a more favorable solution than the traditional methods of transferring produced water. This double-layer solution for containment and leak detection is still in the early stages of development and testing, but discussions are underway with operators and regulators to put one of these into operation in a field test to prove it can be trusted.
Several companies are also looking at the double-layer hose solution to use in colder climates as an effective insulation against freezing temperatures. The goal would be to save a significant amount of the money required to heat the water to prevent it from freezing during a water transfer.
For more information, please visit www.HammerheadIndustrialHose.com.
Authored by Bob Morrison