Tenn. Comp. R. & Regs. 0400-45-06-.09 - GENERAL STANDARDS AND METHODS

(1) Applicability

The provisions of this rule set forth standards and requirements that apply to all classes of injection wells unless specifically excluded or contradicted by provisions applicable to a particular class of well.

(2) Supervisory Standard

All phases of well construction, testing and operation shall be supervised by a person who is knowledgeable and experienced in practical drilling engineering and who is familiar with the special conditions and requirements of injection well construction.

(3) Area of Review

(a) Descriptions of the area of review are subject to approval by the Commissioner according to either subpart 4(i) or (ii) of this subparagraph. The Commissioner may solicit input from the owners and operators of injection wells within the State as to which method is most appropriate for each geographic area or field. In no event shall the boundary of an area of review be less than a radius of one (1) mile from any injection well covered by the appropriate authorization. The following factors are to be included in the description:

1. Chemistry of the injection and formation fluids;

2. Hydrogeology, including the direction of ground water movement;

3. Ground water use and dependence; past, present, and future, as documented by public record; and

4. The area of potential impact as determined by either subpart (i) of this part the calculated zone of endangering influence or subpart (ii) of this part a fixed radius.

(i) Zone of endangering influence

(I) The zone of endangering influence shall be:

I. In the case of application(s) for well permit(s) under Rule 0400-45-06-.08, that area the radius of which is the lateral distance in which the pressures in the injection zone may cause the migration of the injection and/or formation fluid into an underground source of drinking water; or

II. In the case of an application for an area permit, the project area plus a circumscribing area the width of which is the lateral distance from the perimeter of the project area, in which pressures in the injection zone may cause the migration of the injection and/or formation fluid into an underground source of drinking water.

(II) Computation of the zone of endangering influence may be based upon the parameters listed below and should be calculated for an injection time period equal to the expected life of the injection well or pattern. The following modified Theis equation illustrates one form which the mathematical model may take.

r='(2.25KHt / S10^x) ^1/2

where:

X = 4[PI]KH(h_w-h_boXS_pG_b / 2.3Q

r = Radius of endangering influence from injection well (length)

K = Hydraulic conductivity of the injection zone (length/time)

H = Thickness of the injection zone (length)

t = Time of injection (time)

S = Storage coefficient (dimensionless)

Q = Injection rate (volume/time)

h_bo = Observed original hydrostatic head of injection zone (length) measured from the base of the lowermost underground source of drinking water

h_w = Hydrostatic head of underground source of drinking water (length) measured from the base of the lowermost underground source of drinking water

S_pG_b = Specific Gravity of fluid in the injection zone (dimensionless)

(pi) = 3.142 (dimensionless)

The above equation is based on the following assumptions:

I. The injection zone is homogeneous and isotropic;

II. The injection zone has infinite areal extent;

III. The injection well penetrates the entire thickness of the injection zone;

IV. The well diameter is infinitesimal compared to "r"; when injection time is longer than a few minutes; and

V. The emplacement of fluid into the injection zone creates instantaneous increase in pressure.

(ii) Fixed radius

(I) In the case of application(s) for a well permit(s), a fixed radius around the well of not less than one mile may be used.

(II) In the case of an application for an area permit, a fixed width of not less than one mile for the circumscribing area may be used.

In determining the fixed radius, the following factors shall be taken into consideration: chemistry of the injected and formation fluids; hydrogeology; population and ground-water use and dependence; and historical practices in the area.

(b) The Commissioner may require an owner or operator of an existing or proposed injection well to submit information necessary to establish the area of review.

(4) Mechanical Integrity Sandards

(a) An injection well has mechanical integrity if there is no significant leak in the casing, tubing or packer, and if there is no significant fluid movement into USDWs through vertical channels in and adjacent to the injection well bore hold.

(b) The following tests shall be used to evaluate the mechanical integrity of an injection well:

1. Monitoring of annulus pressure, or pressure test with liquid or gas to detect any leaks in casing, tubing, or packer;

2. Appropriate geophysical logs to detect any fluid movement through vertical channels in and adjacent to the injection well borehole.

(c) The Commissioner may allow the use of tests to evaluate mechanical integrity other than those listed in this rule if such tests have been approved in writing by the Commissioner and, if the Commissioner receives authority for an underground injection control program from the U.S. E.P.A., the E.P.A. Administrator or his designee.

(d) Methods and standards generally accepted in the industry shall be applied in conducting and evaluating the tests required by this paragraph.

(5) Corrective Action Standards

(a) Standards

1. Applicants for injection well permits shall identify the location of all known wells within the area of review which penetrate the injection zone, or in the case of Class II wells operating over the fracture pressure of the injection formation, all known wells within the area of review penetrating formations affected by the increase in pressure. For such wells which are improperly sealed, completed or abandoned, the applicant shall also submit a plan consisting of such steps or modifications as are necessary to prevent movement of fluids into USDWs.

(b) requirements

1. Any permit issued for an existing injection well (other than a Class II well) requiring corrective action shall include a compliance schedule requiring any corrective action accepted or prescribed shall be completed as soon as possible.

2. No permit for a new injection well may authorize injection until all required corrective action has been taken.

(c) Injection pressure limitation

The Commissioner may require as a permit condition that injection pressure be so limited that pressure in the injection zone does not exceed hydrostatic pressure at the site of any improperly completed or abandoned well within the area of review. This pressure limitation shall satisfy the corrective action requirement. Alternatively, such injection pressure limitation can be part of a compliance schedule and last until all other required corrective action has been taken.

(d) In determining the adequacy of corrective action to prevent fluid movement into or between formations containing USDWs, the following criteria and factors shall be considered by the Commissioner:

1. Nature and volume of the injected fluid;

2. Nature of native fluids, and by-products of injection;

3. Potentially affected population;

4. Geology;

5. Hydrology;

6. History of the injection operation;

7. Completion and plugging records;

8. Abandonment procedures in effect at the time the well was abandoned; and

9. Hydraulic connections with formations containing USDWs.

(e) Class III wells only

When setting corrective action requirements, the Commissioner shall consider the overall effect of the project on the hydraulic gradient in the potentially affected USDWs, and the corresponding changes in potentiometric surface(s) and flow direction(s) rather than the discrete effect of each well. If a decision is made that corrective action is not necessary based on the determinations of this paragraph, the monitoring program required in Rule 0400-45-06-.12 shall be designed to verify the validity of such determinations.

(6) Plugging and Abandonment Standards

(a) An injection well, or a test or monitor well associated with an injection well, must be abandoned and plugged when:

1. the well is no longer usable for its intended purpose or other purpose as approved by the Commissioner; .

2. the well poses a potential threat to the quality of the waters of the state; or

3. the well has not been operated for two (2) years.

(b) When it is necessary to plug and abandon a well covered by these regulations, an application for a plugging and abandonment permit will be submitted to the Commissioner on the form prescribed. The application will include:

1. Reasons for abandonment;

2. A copy of the approved plugging and abandonment plan which was submitted with the application for construction or operation permits; and

3. Any modifications deemed necessary to the previously approved plugging and abandonment plan.

(c) The owner/operator of an abandoned injection well or facility may be required to submit all pertinent records of construction, operation and abandonment to the Commissioner within a period of not less than one year following the date of abandonment.

(d) Any well that is to be permanently plugged and abandoned shall be completely filled and sealed in such a manner that vertical movement of fluid either into or between formation(s) containing USDWs through the bore hole is not allowed. The proposed method of filling and the type of material to be used shall be approved by the Commissioner.

(e) As a minimum, permanent seals must be placed in the bore hole opposite (1) the lowermost confining bed, and (2) each intermediate confining bed between successive formation(s) containing USDWs.

(f) Seals intended to prevent vertical movement of water in a well bore hole shall be composed of cement, sand-and-cement, or concrete or other sealing materials demonstrated to the satisfaction of the Commissioner to be effective.

(g) The minimum length of a seal required in subparagraph (f), of this paragraph, shall be 20 feet.

(h) The bore hole above the uppermost formation(s) containing a USDW shall be filled with materials less permeable than the surrounding undisturbed formations, the uppermost five (5) feet of the bore hole (at land surface) shall be filled with a material appropriate to the intended use of the land.

(i) The materials used to fill spaces between well seals shall be filled with disinfected dimensionally stable materials, compacted mechanically if necessary to avoid later settlement except that cement, cement and sand, and concrete do not require disinfection. Disenfection of well filling materials shall be accomplished by using chlorine compounds such as sodium hypochlorite or calcium hypochlorite.

(j) Temporary bridges may be used to avoid having to fill very deep holes below the deepest point at which a permanent seal is required. Temporary bridges used to provide a base for a permanent seal shall consist of materials approved by the Commissioner.

(k) After a cessation of operations of two years, the owner or operator shall plug and abandon the well in accordance with the plan unless he: .

1. Provides notice to the Commissioner; and

2. Describes actions or procedures, satisfactory to the Commissioner that the owner or operator will take to ensure that the well will not endanger USDWs during the period of temporary abandonment. These actions and procedures shall include compliance with the technical requirements applicable to active injection wells unless waived by the commissioner.

(7) Placement of sealing materials

(a) Approved sealing materials used in abandonment operations shall be introduced at the bottom of the well or interval to be sealed and placed progressively upward to the top of the well. All such sealing materials shall be placed in such a way as to avoid segregation or dilution of the sealing materials. The method of emplacing materials shall be approved by the Commissioner. Dumping sealing material from the top of the well shall not be allowed.

(b) Permanent seals shall be placed in wells or bore holes opposite confining beds between aquifers which are identifiable as, or are suspected of being, hydraulically separated under natural, undisturbed conditions. After the required seal has been installed, the remainder of the confining zone between formations containing USDWs may be filled with sand, sand and gravel, or other rock material acceptable to the Commissioner.

(8) Special Conditions

(a) The permanent sealing of flowing wells or wells that have a positive shut-in pressure head at the land surface shall be accomplished only after the wells have been prepared in such a way as to prevent any backflow of water or other fluids at the land surface. This can be accomplished by introducing high specific gravity fluids at the bottom of the bore hole and filling the hole with the fluid until all flow ceases or the shut-in pressure is reduced to zero. If the displaced fluid constitutes a contaminant, special handling will be required to avoid any threat to USDWs.

(b) Prior to abandonment, any Class I or Class III well or any monitoring well that extends to the top of the shallowest injection zone shall be sealed from the top of the shallowest injection zone to the land surface with neat cement grout or an approved equivalent cementitious material such as neat cement with a maximum of 5 percent by weight of commercially processed bentonite.

(c) The following shall be considered in determining the adequacy of a plugging and abandonment plan for injection wells:

1. The type and number of plugs to be used;

2. The placement of each plug including the elevation of the top and bottom;

3. The type, grade and quantity of plugging material to be used;

4. The method of placement of the plugs;

5. The procedure used to plug and abandon the well;

6. Any newly constructed or discovered wells, or information, including existing well data, within the area of review; .

7. Geologic formations present including but not limited to type of strata, structure and location of any aquifer;

8. Economic conditions; and

9. Such other factors that may affect the adequacy of the plan.

(9) Verification of Procedures

(a) Except under emergency conditions the Commissioner is to receive thirty (30) days advance notice of the intent to plug and abandon either an injection or monitoring well in order to permit Departmental personnel to witness the procedure.

(b) Within ninety (90) days after completion of plugging, the permittee shall provide to the Commissioner documentation that the well was adequately plugged and abandoned.

(10) Evidence of financial responsibility shall be demonstrated to accomplish all actions required under these rules, including all plugging and abandonment activities. This financial responsibility requirement does not apply to those Class V wells which are permitted by rule.

(11) The Commissioner may require, by written notice on a selective well-by-well basis, an owner or operator of an injection well to establish and maintain records, make reports, conduct monitoring, and provide other information as is deemed necessary to determine whether the owner or operator has acted or is acting in compliance with T.C.A. § 69-3-101 et seq., Tennessee Water Quality Control Act or its implementing regulations.

(12) All injection wells must be placed on a plat with the Register of Deeds by the seller of the individual properties that the injection well is located on or the injection zone is beneath. The owner/operator of the injection well shall have contractual agreement for access to the injection well at all reasonable times.

(13) Any person owning or operating an injection well shall keep the Commissioner advised of his or her current address and must readily accept all mail sent by the Commissioner. For the purposes of this rule, registered or certified mail sent with proper postage to the registered owner or operator's last known address shall be considered adequate notification regardless of whether the mail is accepted or returned unclaimed.

Notes

Tenn. Comp. R. & Regs. 0400-45-06-.09

Original rule filed September 12, 2012; effective December 11, 2012. Rule renumbered from 1200-04-06.

Authority: T.C.A. §§ 69-3-101 et seq. and 4-5-201 et seq.