With all the positive movements in the world of produced water, I continue to see the same problems crop up, and it’s time we address these issues head on. So, let’s dive in, no pun intended.
We are expecting an oil and gas resurgence in the U.S., with the new Trump administration and their “drill baby drill” mentality. The rollback of regulations and obstacles to increase oil production is all generally seen as a positive.
Produced water challenge. Yet, we see so much uncertainty when it comes to produced water. What makes produced water challenging is the lack of consistency. We are dealing with volumes that ebb and flow and contaminant concentrations that fluctuate. We are rarely at steady state. We rely on recycling as a completion fluid that requires volumes in excess of production, requiring storage, and then we only recycle part-time. Even the “drill baby drill” mentality plays a role, as oil prices have declined, and we see a slowing down in frac activity that drives the demand for recycling.
Then there’s seismicity; earthquakes are shutting in or reducing disposal well capacity, as everybody goes through a mad dash to find new capacity. All these gears and dials moving at different speeds and directions and sometimes turning off completely. Welcome to the world of produced water. The only consistency is inconsistency.
The root of this problem is that for years, produced water was treated like oilfield garbage. You generated it, and you threw it away. Nobody studied it or had quality control. In fact, quality control and garbage have had a bad history. Ever look at a trash can sorted for recyclables, food waste and garbage? As you throw your recyclables away, you see food waste and vice versa. Garbage is treated like garbage, and nobody respects the process.
Then, the unconventional oil movement starts, and we are generating and using more water. But seismicity rears its head and, all of a sudden, produced water is important. “You mean I have to shut in my producing wells, because I have nowhere for my produced water to go?” Now, produced water gets its own department, and the need for managing produced water is elevated in importance, but it’s still managed like garbage.
Updates of infrastructure and technology needed. We have outdated infrastructure and technology that need to be updated and reconsidered. Tank batteries and gun barrel systems are like using a rotary phone today. I can’t count the number of times that I’ve seen a clean pit one day and an oil layer the next because of an upset. I know this is going to upset people, but we developed a specification for produced water designed by water treatment providers and that has no connection to frac compatibility or oil production. Not only does this standard just increase cost, but it is also largely ignored or tested improperly.
Recycled water situation. Now, consider that this “recycled water standard” is used to design large-scale water treatment facilities. Consider that recycling has peaks and valleys, and you’re competing with other providers for work, and your large-scale facility is now suffering from low utilization while it is overdesigned for its application.
I say this, because recycled water is used to carry sand to make a completion fluid. This sand can have 10% fines and sometimes more. These fines are TSS (Total Suspended Solids) in the final product and will be 100 times higher than the original produced water. Not all TSS is the same, and some can cause bridging and fouling, but that type of TSS—call it 10 micron and larger—drops out earlier in the process at the tank batteries, in the gathering systems, causing maintenance issues and then in the gun barrels. But let’s say you ignore all of this and put your treated water in a pit for storage. Now, dust loading is adding more TSS, and you are probably close to where you started, but still significantly lower than when you add the sand.
I think this level of treatment would be justified at the disposal well, to improve oil recovery and lower injectivity pressure by developing cleaner water. This should have a beneficial impact on seismicity. I see where you can justify this extra treatment, but most disposal wells operate on narrow margins, so they don’t want the extra cost.
Now let’s bring up the topic of oil theft. It’s a common problem in the oil field, one I’m not sure we have a handle on, but it has become relatively organized. What we have is a broken water management system in a highly volatile industry. So, what do we do?
One operator has already tried this, but you could redesign the tank battery. It is a source of emissions and spills. Build an enclosed system and improve your oil recovery, eliminate your spills, and eliminate or significantly reduce your emissions. Tank batteries are typically in two capacities—50,000 bpd and 100,000 bpd and sometimes peaking at 150,000 bpd.
So, build out 50,000-bpd modules that you can relocate and move. As I mentioned, an operator tried this, and the increased oil recovery paid for the whole system. They didn’t even evaluate gathering system maintenance or improved injectivity at the disposal wells; the increased oil recovery offset the whole system. So, maybe there is more oil theft than we realize. Now, your treatment for recycling is eliminated, as it’s been done upstream. You may need a little bacteria control, but you reduced 50% to 75% of your recycling cost, let alone savings in the gathering systems and improved injectivity at the disposal well.
Then there is desalination and beneficial reuse. This is where our industry is headed, and you have a head start, because you have already completed your pre-treatment at the tank battery. As a result, you reduced your cost for desalination. But here is where we run into a problem. We have an antiquated regulatory system that prevents produced water discharges, but the current administration has announced that they will change this situation, paving the way for beneficial reuse and agricultural reuse. The goal is to reduce reliance on the disposal well network. Again, I think we are looking at it all wrong. Ag reuse is seasonal and add that to an already complex peak-and-valley flow, and you’ve just added another layer of complexity.
So, here is what I see as the “grand plan.” You build a network of recharge basins for groundwater recharge. This is already being done with treated municipal sewer water, which I consider way riskier than produced water. You can fill these basins 24/7—no more seasonality. There are grants for groundwater recharge. You can draw from these basins, if needed, to supply ag and you provide a consistent outlet for treated produced water.
Your concentrated brine from your desalination process continues to go to disposal wells, and then you establish an evaporation plan to add capacity with portable evaporators when capacity peaks. You continue to recycle at a lower cost, and water has gone from a liability to a resource while reducing your overall cost, provided you can get the cost offset for the groundwater recharge. If you follow the Water Positive trend, they expect this to be the new Carbon Market with Water Markets, opening a market to sell water that can offset all of the desalination expense.
From a water-positive standpoint, the oil and gas sector becomes the largest water-positive industry in the world. Produced water deserves a makeover. We need to stop the madness and take a step back and treat it with the respect it deserves. We need to stop looking at segments of the produced water cycle and look at the whole cycle. Believe me, even with this proposed reworking, there are still big hurdles and complexity to deal with, but let’s start being proactive and less reactive. It’s time for a do-over.
Excuse my rant, as I step off my soapbox and see you all next month. WO
MPATTON@HYDROZONIX.COM / MARK PATTON is president of Hydrozonix, an oil and gas-focused water management company. He is a chemical engineer with more than 25 years of experience developing new technologies for wastewaters and process residuals.