R317-7-10. Technical Requirements for Class I Nonhazardous and Class III Wells

10.1 Construction Requirements

A. Class I Nonhazardous Well Construction Requirements

1. All Class I Nonhazardous wells as defined in Section 7-3.1(B) shall be sited so they inject beneath the lowermost formation containing, within two miles of the well bore, an USDW.

2. All Class I Nonhazardous wells shall be cased and cemented to prevent the movement of fluids into or between USDW's. The casing and cement used in the construction of each newly drilled well shall be designed for the life expectancy of the well. In determining and specifying casing and cementing requirements the following factors shall be considered:

a. depth to the injection zone;

b. injection pressure, external pressure, internal pressure, and axial loading;

c. hole size;

d. size and grade of all casing strings (wall thickness, diameter, nominal weight, length, joint specification, and construction material);

e. corrosiveness of injected fluid, formation fluids, and temperatures;

f. lithology of injection and confining intervals; and

g. type or grade of cement.

3. All Class I Nonhazardous injection wells (except for municipal wells injecting noncorrosive wastes) shall inject through tubing with a packer set immediately above the injection zone or tubing with an approved fluid seal. Alternatives may be used with the written approval of the Director if they provide a comparable level of protection.

The following factors shall be considered in determining and specifying requirements for tubing, packer or alternatives:

a. depth of setting;

b. characteristics of injected fluid;

c. injection pressure;

d. annular pressure;

e. rate, temperature and volume of injected fluid; and

f. size of casing.

4. Appropriate logs and other tests shall be conducted during the drilling and construction of new wells and a descriptive report interpreting the results of such logs and tests shall be prepared by a qualified log analyst and submitted to the Director. At a minimum, such logs and tests shall include:

a. deviation checks on holes constructed by drilling a pilot hole, and then enlarging the pilot hole;

b. Such other logs and tests as may be required by the Director. In determining which logs and tests shall be required, the following shall be considered for use in the following situations:

(1) for surface casing intended to protect USDW's:

(a) electric and caliper logs (before casing is installed);

(b) cement bond, temperature or density log (after casing is set and cemented);

(2) for intermediate and long strings of casing intended to facilitate injection:

(a) electric, porosity and gamma ray logs (before casing is installed);

(b) fracture finder logs;

(c) cement bond, temperature or density log (after casing is set and cemented).

5. At a minimum, the following information concerning the injection formation shall be determined or calculated for new wells:

a. fluid pressure;

b. temperature;

c. fracture pressure;

d. physical and chemical characteristics of the injection matrix; and

e. physical and chemical characteristics of the formation fluids.

B. Class III Construction Requirements

1. All new Class III wells shall be cased and cemented to prevent the migration of fluids into or between underground sources of drinking water. The Director may waive the cementing requirement for new wells in existing projects or portions of existing projects where he has substantial evidence that no contamination of underground sources or drinking water would result. The casing and cement used in the construction of each newly drilled well shall be designed for the life expectancy of the well. In determining and specifying casing and cementing requirements, the following factors shall be considered:

a. depth to the injection zone;

b. injection pressure, external pressure, internal pressure, and axial loading;

c. hole size;

d. size and grade of all casing strings (wall thickness, diameter, nominal weight, length, joint specification, and construction material);

e. corrosiveness of injected fluids and formation fluids;

f. lithology of injection and confining zones; and

g. type and grade of cement.

2. Appropriate logs and other tests shall be conducted during the drilling and construction of new Class III wells. A descriptive report interpreting the results of such logs and tests shall be prepared by a qualified log analyst and submitted to the Director. The logs and tests appropriate to each type of Class III well shall be determined based on the intended function, depth, construction and other characteristics of the well, availability of similar data in the area of the drilling site, and the need for additional information that may arise from time to time as the construction of the well progresses. Deviation checks shall be conducted on all holes where pilot holes and reaming are used, unless the hole will be cased and cemented by circulating cement to the surface. Where deviation checks are necessary they shall be conducted at sufficiently frequent intervals to assure that vertical avenues for fluid migration in the form of diverging holes are not created during drilling.

3. Where the injection zone is a formation which is naturally water-bearing the following information concerning the injection zone shall be determined or calculated for new Class III wells or projects:

a. fluid pressure;

b. fracture pressure; and

c. physical and chemical characteristics of the formation fluids.

4. Where the injection zone is not a water bearing formation, only the fracture pressure must be submitted.

5. Where injection is into a formation which contains water with less than 10,000 mg/l TDS, monitoring wells shall be completed into the injection zone and into any USDW above the injection zone.

6. Where injection is into a formation which does not contain water with less than 10,000 mg/l TDS, no monitoring wells are necessary in the injection stratum.

7. Where the injection wells penetrate an USDW in a area subject to subsidence or catastrophic collapse, an adequate number of monitoring wells shall be completed into the USDW.

10.2 Operation Requirements

A. For Class I Nonhazardous and Class III wells it is required that:

1. Except during stimulation, the injection pressure at the wellhead shall not exceed a maximum which shall be calculated to assure that the pressure in the injection zone during injection does not initiate new fractures or propagate existing fractures in the injection zone. In no case shall the injection pressure initiate fractures in the confining zone or cause the movement of injection or formation fluids into an USDW.

2. Injection between the outermost casing protecting USDW's and the well bore is prohibited.

B. For Class I Nonhazardous wells, unless an alternative to tubing and packer has been approved, the annulus between the tubing and the long string of casings shall be filled with a fluid approved by the Director and a pressure approved by the Director shall be maintained on the annulus.

10.3 Monitoring. The permittee shall identify types of tests and methods used to generate the monitoring data:

A. Class I Nonhazardous well monitoring shall, at a minimum, include:

1. the analysis of the injected fluids with sufficient frequency to yield representative data of their characteristics;

2. installation and use of continuous recording devices to monitor injection pressure, flow rate and volume, and the pressure on the annulus between tubing and the long string of casing;

3. a demonstration of mechanical integrity pursuant to 40 C.F.R. 146.8 at least once every five years during the life of the well; and

4. the type, number and location of wells within the area of review to be used to monitor any migration of fluids into and pressure in the USDW, the parameters to be measured and the frequency of monitoring.

5. Ambient monitoring requirements for Class I Nonhazardous wells found in 40 C.F.R. 146.13(d).

B. Class III monitoring shall, at a minimum, include:

1. the analyses of the physical and chemical characteristics of the injected fluid with sufficient frequency to yield representative data on its characteristics;

2. monitoring of injection pressure and either flow rate or volume semi- monthly, or metering and daily recording of injected and produced fluid volumes as appropriate;

3. demonstration of mechanical integrity pursuant to 40 C.F.R. 146.8 at least once every five years during the life of the well for salt solution mining;

4. monitoring of the fluid level in the injection zone semi-monthly, where appropriate and monitoring of the parameters chosen to measure water quality in the monitoring wells required by Section 7-10.2 of these rules, semi-monthly;

5. quarterly monitoring of wells required by Section 7-10.1(B)(7).

6. All Class III wells may be monitored on a field or project basis rather than an individual well basis by manifold monitoring. Manifold monitoring may be used in cases of facilities consisting of more than one injection well, operating with a common manifold. Separate monitoring systems for each well are not required, provided the owner/operator demonstrates that manifold monitoring is comparable to individual well monitoring.

7. In determining the number, location, construction and frequency of monitoring of the monitoring wells, the criteria in 40 C.F.R. 146.32(h) shall be considered.

10.4 Reporting Requirements

A. For Class I Nonhazardous injection wells reporting shall, at a minimum, include:

1. quarterly reports to the Director on:

a. the physical, chemical and other relevant characteristics of injection fluids;

b. monthly average, maximum and minimum values for injection pressure, flow rate and volume, and annular pressure; and

c. the results of monitoring of wells in the area of review.

2. Reporting the results, with the first quarterly report after the completion of:

a. periodic tests of mechanical integrity;

b. any other test of the injection well conducted by the permittee if required by the Director; and

c. any well work over.

B. For Class III injection wells reporting shall, at a minimum, include:

1. quarterly reporting to the Director on required monitoring;

2. results of mechanical integrity and any other periodic test required by the Director reported with the first regular quarterly report after the completion of the test; and

3. monitoring may be reported on a project or field basis rather than individual well basis where manifold monitoring is used.

10.5 Plugging and Abandonment Requirements

A. Prior to abandoning Class I Nonhazardous and Class III wells, the well shall be plugged with cement in a manner which will not allow the movement of fluid either into or between underground sources of drinking water. The Director may allow Class III wells to use other plugging materials if he is satisfied that such materials will prevent movement of fluids into or between underground sources of drinking water.

B. Placement of the cement plugs shall be accomplished by one of the following:

1. the Balance Method;

2. the Dump Bailer Method;

3. the Two-Plug Method; or

4. an alternative method approved by the Director which will reliably provide a comparable level of protection to USDW's.

C. The well to be abandoned shall be in a state of static equilibrium with the mud weight equalized top to bottom, either by circulating the mud in the well at least once, or by a comparable method prescribed by the Director, prior to the placement of the cement plug.

D. The plugging and abandonment plan required in Section 7-9 shall, in the case of a Class III well field which underlies or is in an aquifer which has been exempted, also demonstrate adequate protection of USDW's. The Director shall prescribe aquifer cleanup and monitoring where he deems it necessary and feasible to insure adequate protection of USDW's.

10.6 Information to be Considered by the Director. Requirements for information from well owners or operators and evaluations by the Director for the issuance of permits, approval of well operation or well plugging and abandonment of Class I Nonhazardous injection wells are found in 40 C.F.R. 146.14 and Class III injection wells are found in 40 C.F.R. 146.34.