Greater attention, rightfully, is now paid in the oil patch to our first natural resource: water. From all fronts affected, parties are more aware of the proper stewardship of water. This stewardship does not come without controversy. That famous geologist Mark Twain was correct: Whiskey is for drinking, water is for fighting. The North Dakota State Water Commission projects the amount of water needed for developing a Bakken Formation well for natural gas production at approximately three acre feet. The required water must come from a freshwater source.
With the oil patch growth through 2019, Bakken wells could require as much as 51,000 acre feet (a.f.) of water. The general uses of water in the oil patch include well drilling and completion, well production, the so called use of maintenance water which requires fresh water sources, and after-production. I will focus this article on the management and disposal of used water in the ‘after production phase’ which water is often referred to as produced water or saltwater. The other important aspects of water uses, as well as tribal regulations and water law, will be left for another discussion.
During hydraulic fracturing – commonly known as fracking – water mixed with industrial chemicals and proppants (a mix of sand or ceramic particles) are forced into the well system to release oil and gas. The waste water from the process is the so called produced water or salt water. Produced water is the largest volume by-product from an oil and gas well. Along with the chemicals used during the drilling produced water is highly saline, usually 10 times that of ocean water. Its improper use or disposal would damage soil productivity or pollute near-surface water aquifers used for irrigation and drinking water. North Dakota statutes specifically prohibit this remaining produced water from polluting any freshwater supply in the state.
Disposal wells are the most common final method for removal of unusable produced water or saltwater. North Dakota currently has 470 active saltwater disposal wells. The well process involves injecting the produced saltwater and associated wastes into naturally occurring subsurface formations called confining geologic zones. As technology advances, the industry has other non-well options for produced water management. Such technology includes obtaining fracking water from saline groundwater sources, or from municipal waste water. A fresh water source such as an aquifer must be allowed to replenish itself (recharge), so the careful stewardship and use of water in the oil patch continually relevant. Let us look at the current practice of disposal well procedures and issues.
Upon returning to the surface there are two common methods of handling produced water:
- Re-injection into the oil-producing formation for enhancing oil and gas production
- Injection into an underground formation that naturally contains saltine water. This second method is also known as Salt Water Disposal (SWD) which are also called disposal wells.
SWD is considered the most economic final disposal method. The U.S. Environmental Protection Agency classify these wells as class II wells used to inject fluids associated with oil and natural gas production operations.
Under the guidelines of the Underground Injection Control Program established by the federal Drinking Water Safe Act, North Dakota has imposed regulations:
- For pits and ponds containing saltwater liquids and brines produced by the hydraulic fracturing operations
- Governing the process of underground injection wells. A technical permit application is required for these SWD wells.
A disposal well must go through an application and approval process. This is also called the siting of a well. The information the state studies from an application is comprehensive and involves detailed geologic data. A disposal well must also complete a mechanical integrity test before it becomes properly permitted and can operate. Information and data which must be submitted, and reviewed, before the state would approve an SWD well permit application include:
- Geologic name of lowest known fresh water zone
- A plat depicting the area and detailed description of the location, well name, and operator of all wells in the area of review. The area wide plat must include: nearby injection wells, producing wells, plugged wells, abandoned wells, drilling wells, dry holes, and water wells. The plat must also show seismic faults, if known or suspected
- Testing and recording the original bottom-hole injection of the well
- A description of the proposed injection program
- A quantitative analysis from the two nearest fresh water wells
- A written notice to all landowners within the area of review who must be notified of the proposed injection well.
- This notice informs the landowners that comments or objections may be submitted
- Schematic drawings of the well bore and surface facility construction.
The controversy surrounding salt water disposal wells concern spills, potential leaks and earthquakes. Spills occur. These events are saltwater surface spills not related to the disposal well or to the well integrity of a properly permitted well. Spills happen because of human error and bad equipment. As with all Bakken oil and gas production procedures, it can be said: most in the industry do it right, but some just do it. Saltwater spills occur on the surface, and are often a mechanical malfunction or error in human judgment.
The risk of a spill from a saltwater disposal well is not from a properly permitted well itself. When a spill occurs it is usually during the act of storing or delivering wastewater to the disposal well. Consider for example that there are 470 active operating disposal wells in North Dakota, but more than 2100 saltwater pipelines, and it is easier to understand that the ‘getting to the well’ is where problems arise. New rules have recently been promulgated by the Industrial Commission for ‘underground gathering pipelines’. These regulations will address the construction and deconstruction [shutdown] of saltwater service pipelines.
Do disposal wells contaminate water wells and aquifers? The question is more properly stated: Do disposal wells fail or leak? Thousands of disposal wells have been permitted in the U.S. In 2012 a company called Halek Operating ND LLC was fined civilly and charged criminally by the Industrial Commission for illegal action and operating a disposal well after having been ordered to shut-in the well. In that case, among other things, the administrative law judge also found that the company had operated the disposal well without first completing a mechanical integrity test on the well. The state found no damage to aquifers from the illegal activity. I know of no failures or leaks from properly permitted disposal wells located in North Dakota and South Dakota in my lifetime. And information from both states’ regulatory agencies report that such events have not occurred.
Do disposal wells cause earthquakes? Thousands of disposal wells have been permitted in the U.S. The state of Arkansas is in a region of the continent that has recognized natural earthquake activity. Because the Arkansas Oil and Gas Commission thought that disposal wells may have been causing or aggravating earthquakes in the state it ordered a study. After the study was completed in 2011 the state regulatory authority established a moratorium on new and on operating disposal wells in an area that resulted in the closure of 4 of the state’s 700 disposal wells. Natural earthquakes are more likely to occur of course in earthquake-prone geology. A region prone to natural earthquakes is more likely to be the place where a quake caused or affected by a disposal well might occur. The Bakken and Williston basin are not known as geologically earthquake-prone areas of the continent, and the state permitting process does not authorize active disposal wells near a fault line. I know of no earthquakes caused by properly permitted disposal wells in North Dakota and South Dakota in my lifetime. And information from both states’ regulatory agencies report that such events have not occurred.
David Ganje of Ganje Law Offices practices natural resources, environmental and commercial law. The website: lexenergy.net