Water management: New disposal well requirements

MARK PATTON, CONTRIBUTING EDITOR 

As most of you are aware, we have been seeing increasing reservoir pressures in disposal zones in the Permian basin. These increases in pressure are associated with increasing seismicity (earthquakes). The common practice that has been used in Oklahoma and Ohio is to restrict disposal volumes in the affected areas, and this practice has essentially mitigated the seismicity issue.  

This is essentially the direction that Texas and New Mexico have pursued. But the Permian basin is under tremendous scrutiny as the largest oil producing basin in the U.S. and the most prolific produced water producer. Volumes up to 15 MMbpd are reported, even larger numbers by others. Part of this scrutiny has a lot to do with the sheer volume, but articles by Bloomberg and The Wall Street Journal point to this is a crisis. 

New Mexico has taken on a more aggressive approach than Texas, and the criticism is that the Texas Railroad Commission (RRC) isn’t doing enough. And if you listen to the environmentalists, we are heading into a crisis. So, with that, I would like to take the time to talk about what is really being done. In general, we have already seen, through the actions taken by New Mexico and Texas, a subsiding of earthquake frequency from steadily increasing to flat. We will see if this trend continues. 

New disposal well permitting. Early this year, Texas announced that they would be changing the permit requirements for new disposal wells. These requirements became effective June 1, 2025. The key components of these new requirements is an expanded Area of Review (AOR) for the injection site limits on injection pressure and limits on daily injection volume. This increases the sensitivity of adding disposal wells in an area that may already have been impacted. And although this makes the permitting more onerous, I believe it is necessary to ensure we maintain the integrity of our disposal network. This network is critical and without it, we will see wells shut in and experience diminished oil production., 

AOR expansion. The AOR expansion has gone from ¼ mile to ½ a mile and 2 miles. Under the new requirements, the applicant has to assess old and unplugged wells. In the ½-mile review, casing and cementing information is required, and competent cementing is required in all wells within the ½-mile interval. All inactive wells will require annular cement and wellbore plugs. The goal here is to prevent fluids from migrating. Within the 2-mile radius, the AOR will focus on unknown or orphan wells. If they are encountered, then there will be a deduction in the applicants’ injection pressure. This puts the pressure on the applicant to address and or plug these wells in, to avoid the pressure reduction requirements. 

Injection pressure and volume. The next two changes involve injection pressure and volume. The intent with the injection pressure changes is to ensure that formation pressures will not exceed the fracture gradient, again ensuring the integrity of the disposal reservoir. Volumes will be limited by using a scoring method that includes bottomhole pressure. The Maximum Daily Injected Volume (MDIV) becomes a permit condition that will limit daily volume, but also function as an instant rate limit (MDIV divided by 1,440 minutes/day). This will result in a Minimum Injection Rate (MIR). 

Permian disposal well review. This entire process is referred to as the “Permian Disposal Well Review” and will additionally include bottomhole pressure measurements, initial and periodic. Daily injection volumes and surface injection pressures are reported monthly to TexNet, fracture gradient review and more.  

Although this may seem onerous, there are many benefits, and I actually have to applaud the RRC efforts to address the concern over increasing pressures. 

Orphan and zombie wells. One of the recent areas of attack has been over the orphan well and zombie well problem. Let’s start by defining these terms. Orphaned wells are known wells that were abandoned, usually because of the operator’s bankruptcy or just walking away. These orphan wells can be closed properly, unproperly, or not closed at all. Zombie wells are unknown. There is no record of them, and they are usually unpermitted wells. The criticism has been that these wells are leaking and contaminating the land and thus are a problem as big as seismicity. The permitting changes help to identify these wells and get this program under control. But that seems to infer that the program was out of control, which is in no way correct. 

RRC and orphan wells. In 2025, the RRC plugged 1,101 orphan wells and has 50 rigs working, just to plug orphan wells. Since it started the program in 1984, the RRC has plugged more than 46,000 orphan wells and budgeted over $100 million for the task in 2025. So, by no means have they been passively addressing the problem, I would say they are being aggressive.  

The other issue is the Zombie wells; wells we don’t know about. In reporting on this topic, it seems like they are popping up all over. But in talking to the RRC, a busy year is 10 Zombie events. It appears not to be as big a problem as we would think, but the new disposal permitting guidelines help to identify these wells and then provide the incentive for the applicant to address and plug these wells or suffer a permit volume restriction. I would say that the RRC is taking this issue seriously and approaching it from a variety of angles. You may be surprised that in their annual report the RRC states that there were 460,388 oil and gas well facility inspections. This certainly doesn’t sound like what The Wall Street Journal and Bloomberg reported. 

In fact, the whole industry is reacting, as I would expect. There is a push toward permitting beneficial reuse and discharge of produced water. There are at least five permit applications in process, with one already in draft permit form. Depending on the environmental group response, we could even see a discharge permit in 2026, but I know the opposition may prevent this. But we are seeing many movements to help address disposal reservoir pressure. Chevron is presenting a paper on their use of radar to monitor subsurface fluid movement and fault slips near disposal wells. ExxonMobil shared a paper last year on how they are using machine-learning to model and predict seismicity in their disposal wells. 

Necessity is the Mother of Invention. Between new outlets for produced water from beneficial reuse, discharge, industrial reuse like cooling water, especially for Data Centers, as well as optimizing and reducing reservoir pressures, we are seeing a transition in produced water management. It is a much-needed transition, but it will be interesting to see what the next three to five years brings, as we move from a disposal-dominated produced water management program to a more diverse one. I am excited to see where we go from here.