Injection Wells Frequently Asked Questions (FAQ)

Updated: 10/11/13

What is an injection well?

Injection wells allow for the placement of fluids into the ground. The United States Environmental Protection Agency (EPA) has created six "classes" of injection wells. In Kansas, Class I, III, IV, V, and VI injection wells are regulated by either the Kansas Department of Health and Environment (KDHE) or the EPA.

The Kansas Corporation Commission (Commission) regulates Class II injection wells. Class II injection wells are used to inject fluids associated with oil and gas production into the ground. Class II injection wells are the type of wells addressed in this FAQ document.

How many Class II injection wells are there?

In Kansas, there are approximately 16,600 permitted injection wells.

What types of Class II injection wells are there?

Class II injection wells come in two varieties: disposal wells and secondary/enhanced oil recovery wells.

Disposal wells are used to inject fluids into rock formations that do not produce oil or gas. The formations are isolated from usable quality groundwater and are sealed above and below by unbroken and impermeable rock formations. There are about 5,000 disposal wells in Kansas.

Secondary/enhanced oil recovery wells are used to inject fluids into formations/reservoirs that produce oil or gas. The formations are also isolated. Injection of fluid into these formations often allows for increased recovery of oil or gas reserves. There are about 11,600 secondary/enhanced oil recovery wells in Kansas.

What types of fluid are injected into Class II wells?

Two types of fluid are typically injected into Class II wells.

The first fluid is saltwater. Saltwater is sometimes referred to as brine water, or produced water. Oil and gas reservoirs often contain significant amounts of saltwater. When oil and gas are produced, saltwater is also produced. Operators must dispose of the saltwater in a manner that will not pollute surface or subsurface waters. Often, the most effective and economical way to do that is to inject the saltwater back into the rock formation.

The second fluid is hydraulic fracturing fluid. Fracturing fluid is primarily water, but may also include sand and various additives. Used hydraulic fracturing fluid must be disposed of in a manner that will not pollute surface or subsurface waters, and operators often dispose of the fluids down disposal wells.

Saltwater represents the overwhelming majority of the fluid injected into Class II wells.

What else might be in saltwater?

It is possible that small quantities of drilling mud, well treatment fluids, or residual hydrocarbons will be in the produced saltwater. These are generally found in no more than trace quantities. Fluids must be injected into formations that are isolated from usable quality groundwater, sealed above and below by unbroken, impermeable rock formations.

Aside from water, what else might be in hydraulic fracturing fluid?

In small quantities, sand and various additives may be found in hydraulic fracturing fluid. Interested citizens can view more data on these additives at These fluids must also be injected into formations that are isolated from usable quality groundwater, sealed above and below by unbroken, impermeable rock formations.

Why is hydraulic fracturing fluid injected instead of recycled?

Some hydraulic fracturing fluid is recycled, although a majority is disposed of by injection. The primary reason cited by operators for injecting the fluid is that it is significantly less expensive than recycling.

Does hydraulic fracturing use a lot of water?

Yes and no. Although a hydraulic fracturing treatment may use hundreds of thousands of gallons of water, hydraulic fracturing accounts for much less than 1 percent of statewide water use.

Operators must have proper authority to use water in hydraulic fracturing, and industry continues to look for technological advances to reduce fresh water use. The Commission recognizes the value of fresh, usable water to the citizens of Kansas.

What about truck traffic and road damage from injection activities?

The Commission does not have authority to regulate truck traffic or road damage. Concerned citizens should contact relevant county or municipal governments, or the Kansas Department of Transportation, which may be able to address these issues.

Where are the Commission's regulations for Class II injection wells?

The Commission has three statutory duties: to protect correlative rights, to prevent waste, and to protect fresh and usable water. With injection wells, the primary concern is to protect fresh and usable water.

The Commission's regulations for injection wells are found in K.A.R. 82-3-400 through K.A.R. 82-3-412. The regulations are specifically tailored to protect underground sources of drinking water from harm from improper injection. The regulations follow national guidelines under the federal Safe Drinking Water Act regarding surface and groundwater protection.

How does the Commission regulate Class II injection wells?

Within the Commission, the Underground Injection Control (UIC) department has primary responsibility for Class II injection wells.

There are three main aspects to the regulatory process. First, an injection well must be properly constructed. Second, an injection well must be properly permitted. Third, the Commission monitors all injection operations.

What are the construction standards for an injection well?

Commission rules for the construction of all oil and gas wells, and also injection wells, are found in K.A.R. 82-3-106. The rules require multiple layers of cement and steel casing to ensure that usable groundwater is not impacted by injection operations.

Specifically, an injection well's construction standards require three layers of casing.

The first protective layer is surface casing. Surface casing consists of a steel pipe, partially or totally encased in cement, reaching from the surface to below the deepest usable groundwater level. Surface casing acts as a protective sleeve through which deeper drilling occurs.

The second protective layer is the production casing. Production casing is steel pipe, encased in cement, reaching from the surface to the well's total depth. Production casing goes inside the surface casing.

The third protective layer, used by most injection wells, is the tubing string and packer. The tubing string and packer conduct fluids down through the production casing to the bottom of the well, where the fluids are injected.

Thus, all three protection layers must fail at the same time to impact groundwater.

What is involved in the permitting process for injection wells?

There are four steps to the permitting process.

First, the operator must file an application. When filing the application, the operator must notify the landowner, as well as all owners of unleased acreage and all oil and gas well operators within a ½ mile radius of the project boundary. The operator must also publish notice in the official county newspaper.

Second, Commission Staff determines whether the operator is in good standing with the Commission.

Third, Commission Staff checks whether the well is properly completed to protect groundwater.

Fourth, Commission Staff conducts an "area of review" study, to confirm that there are no improperly completed, improperly plugged, or abandoned wells within ¼ mile of the proposed injection well. This helps ensure that there is no pathway of migration from the injection zone to usable water.

If Commission Staff identifies an issue, it must be resolved. After Commission Staff determines that the well complies with all rules ensuring protection of fresh and usable water, the Commission will administratively approve the application.

However, if an interested party protests the application, stating reasons why the proposed plan may cause damage to oil, gas, or water resources, then a hearing may be held. Based on the evidence presented, the Commission will either approve or deny the application.

How does the Commission monitor injection wells?

There are three major ways in which the Commission monitors injection wells.

First, operators must report average injection pressures and monthly injection volumes to the Commission. This assures that the well is operating within the authority of the permit.

Second, injection wells are periodically inspected based on several factors, including the operator's compliance record and the injection well's vicinity to sensitive environmental groundwater and public areas. If an inspection indicates a problem, the well must be shut in until the issue is resolved.

Third, each injection well must be tested for mechanical integrity. An initial test, before the well is permitted, must demonstrate that there are no leaks. Afterwards, wells must pass a mechanical integrity test (MIT) at least once every 5 years. Commission Staff sometimes direct operators to conduct MIT's more frequently when troubleshooting potential problems.

Any well that fails an MIT must be immediately shut-in. The operator is then given 90 days to repair the well or to plug it. The Commission's standard MIT is designed to identify small leaks or a loss of well integrity before it becomes a larger problem.

Operators are required to notify the Commission before conducting an MIT. Federal guidelines only require the Commission to witness 25% of MIT's, but Commission inspectors witness over 85% of these tests, as the Commission wishes to ensure protection of fresh water supplies.

Is it possible to look up injection wells on the Commission's website?

Not at this time. You can, however, view maps that include injection wells on the Kansas Geological Survey (KGS) website, at

The KGS website provides many details about oil and gas wells in Kansas. If you cannot find what you are looking for, call the Commission at 316-337-6200. We may be able to assist you.