62-528.410. Well Construction Standards for Class I and III Wells

(1) General Design Considerations.

(a) All Class I and III wells shall be cased and cemented to prevent the movement of fluids into or between underground sources of drinking water, and to maintain the ground water quality in aquifers above the injection zone that may be used for monitoring or other purposes.

(b) All Class I wells shall be designed and constructed so that they inject into a formation which is beneath the lowermost formation containing, within one quarter mile of the well bore, an underground source of drinking water.

(c) In the design specifications for a Class I well, the applicant shall address the problem of corrosion, proposed protective measure(s), and, when appropriate, proposed methods of monitoring. The applicant shall consider thickness and type of cement, number and thickness of casings, casing material, casing coatings, formation fluid (water) quality, injection fluid quality and life expectancy of the well.

(d) For Class I wells all outer surfaces of uncemented casings or portions of casings shall be coated or otherwise protected against corrosion. This protection shall extend for a minimum distance of thirty feet above and below the uncemented portion of the casing.

(e) All Class I injection wells, except those municipal wells (publicly or privately owned) injecting noncorrosive wastes, shall inject fluids through tubing with a packer set immediately above the injection zone, or tubing with an approved fluid seal as an alternative. All existing non-municipal wells constructed without tubing and packer or a fluid seal shall modify their design to incorporate a tubing and packer or fluid seal no later than July 1, 1997, or cease injection unless an alternative to a packer has been approved by the Department under subparagraph 1., below. Existing wells receiving non-municipal waste through a tubing and packer shall not be allowed to remove the tubing and packer as long as injection of non-municipal waste continues unless an alternative to a packer has been approved by the Department under subparagraph 1., below. The tubing, packer, and fluid seal shall be designed for the expected service.

1. The use of other alternatives to a packer shall be allowed with the written approval of the Department. To obtain approval, the applicant shall submit to the Department a written request which shall set forth the proposed alternative and all technical data supporting its use. The Department shall approve the request if the applicant demonstrates that the alternative method will reliably provide a comparable level of protection to underground sources of drinking water.

2. In determining and specifying requirements for tubing, packer, or alternatives, the following factors shall be considered:

a. Depth of setting;

b. Characteristics of injection fluid (chemical content, corrosiveness, and density);

c. Injection pressure;

d. Annular pressure;

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

f. Size of casing.

(f) For Class I wells the following designs are not allowed:

1. Annuli between casings open to the land surface in any injection well, and

2. Monitoring tubes emplaced and cemented in the annulus adjacent to the innermost or injection string of casing.

(g) For all Class I wells, the applicant shall address potential surge and water hammer protection to protect the safety and integrity of any injection well system.

(h) Department approval, as described in subsection 62-528.100(2), F.A.C., is required prior to any of the following:

1. Remedial procedures that alter the basic design specifications, materials, or character of a Class I or III well;

2. Any work requiring the complete removal of the wellhead; or

3. Any injection of fluids other than those authorized under the existing permit.

(2) Exploratory Pilot Hole.

The Department shall require an exploratory pilot hole in any Class I well, or for Class III wells, at any proposed injection well site, and shall require that the hole be drilled in stages. The Department shall waive the requirements of this subsection if the applicant can demonstrate that they are not needed to protect underground sources of drinking water and that waiving the requirements will not adversely affect the successful construction or operation of the well.

(3) Drilling.

A step-by-step drilling plan shall be included in the design specifications for Class I and III wells. The drilling plan shall specify the proposed drilling program, sampling, coring, and testing procedures, and is subject to Department approval.

(a) For Class I wells, a deviation survey shall be run in the pilot hole at least every ninety feet (every three joints) of the portion of the well which is to be cased and at more frequent intervals when necessary to ensure that the casing can be set and centered for cementing. The maximum deviation at each measurement shall not exceed one degree deviation from vertical. The Department recognizes that the design requirements in this section are not necessary in all cases. The Department shall modify these requirements in the construction permit provided that the applicant submits proof that such modification will not adversely affect the successful construction and future operation of the well.

(b) For Class I wells, the Department shall require directional surveys, if, after an analysis of the well design and drilling program, it is needed to verify that the reamed hole has followed the pilot hole. The directional survey shall be conducted during drilling or in the pilot hole and the reamed hole as separate surveys before installation of the casing.

(c) The Department shall require the applicant to demonstrate that when salt is used for density control during drilling it will not adversely affect the establishment of background water quality for monitoring purposes.

(4) Casings.

(a) The casings used in the construction of each newly drilled Class I and III well shall be designed for the life expectancy of the well, and shall be new and unused for Class I wells.

(b) The number, thickness, type of materials, and length of casing shall be sufficient to protect the quality of drinking water resources and the integrity of the well and the confining strata. The final string of casing shall be made of seamless mild steel pipe having a minimum 0.500 inch wall thickness. An applicant who proposes to use pipe composed of other than 0.500 inch wall seamless mild steel for the final casing shall demonstrate that the proposed material and thicknesses will not compromise the integrity or operation of the well.

(c) Exact setting depths of all casings or tubing shall be determined from field data, based on all available information. Department approval shall be obtained prior to installation of the injection casing and the casing which extends to the base of the underground source of drinking water. In order to obtain approval, the permittee shall submit a request to the Department. The Department shall approve the request if the proposed setting depth of the casing or tubing meets the requirements of this chapter and will not adversely affect the operation of the injection well.

(5) Cementing.

(a) The applicant shall submit the proposed cementing program with the design specifications for Class I or III wells. The 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:

1. Depth to the injection zone;

2. Injection pressure, external pressure, internal pressure, and axial loading;

3. Hole size;

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

5. Corrosiveness of injected fluid, formation fluids, and temperatures;

6. Lithology of injection and confining zones; and

7. Type or grade of cement.

(b) Cement must be compatible with the injection fluid, native fluids, and the formation, but in no case less than the quality of American Society of Testing and Materials Type 2 or its equivalent (Standard Specification for Portland Cement, American National Standards Institute/American Society of Testing and Materials C 150-94, 1994, which is incorporated herein by reference).

(c) Applicants shall submit with the design specifications, a list of cement additives which may be needed in the operation. If an additive is not in the design specifications, the applicant shall obtain prior approval for its use from the Department, as described in subsection 62-528.100(2), F.A.C. Accurate records shall be kept and all additives used shall be reported.

(d) During drilling, the use of cement additives approved in paragraph (c) above, water/cement ratio, and the type of water used for mixing shall be determined by the applicant, provided the integrity, containment, corrosion protection, and structural strength of the cement are not significantly affected.

(e) Prior to cementing, the hole shall be conditioned to create optimum bonding of the cement to the casing and formation and to prevent channeling.

(f) Cement placement shall be in such a manner that the purposes and characteristics of the cement are retained, and shall be in accordance with “AWWA Standard for Water Wells”, American Water Works Association A100-90, 1990, which is incorporated herein by reference.

(g) The applicant shall submit his cement testing program with the permit application. The purpose of the cement testing program is to ensure that the cement seal is adequate to prevent migration of fluids in channels, microannular space, or voids in the cement. The methods of testing include:

1. Temperature Survey – shall be run within forty-eight hours after cementing;

2. Cement Evaluation Survey.

(h) During cementing, adequate pressure differentials shall be maintained to prevent collapse or distortion of the casing.

(i) Class I wells.

1. The final string of casing shall have a nominal overdrill of ten inches unless the applicant can affirmatively demonstrate that an overdrill of not less than five inches is sufficient. The annulus surrounding the final string of casing shall have a nominal five inch cement thickness from the bottom of the casing to land surface. The Department recognizes that these design requirements may not be necessary in all cases. The Department shall modify these requirements in the construction permit if the applicant submits proof that such modification will not adversely affect the successful construction and future operation of the well in such a way as to threaten an underground source of drinking water with contamination.

2. The remaining casings shall have a minimum thickness of 2.500 inches of cement surrounding the casings with not less than five inches of overdrill. A nominal ten inch overdrill shall be required with any intermediate string of casing for which an annular monitor tube of up to 2.375 inches maximum outer diameter is to be emplaced. Commensurate increases in the overdrill shall be required for monitor tubes larger than 2.375 inches in outer diameter.

3. The applicant shall include with the cementing program a centralizing program for the purpose of centralizing the casing, to provide adequate annular space around the casing for proper cementing.

(6) Testing During Drilling and Construction of New Class I Wells.

(a) Geophysical surveys and other tests shall be conducted during the drilling and construction of new Class I wells. A descriptive report interpreting the results of such geophysical surveys and tests shall be presented to the Technical Advisory Committee during in-progress reviews, as part of periodic progress reports, or in letter form as appropriate. Such reports shall include field copies of the surveys and test data and analysis results at the level required to support field decisions made during drilling or proposed during in-progress reviews. Such surveys and tests shall include:

1. Deviation checks shall be in accordance with subsection 62-528.410(3), F.A.C. Such checks shall be at sufficiently frequent intervals to assure that vertical avenues for fluid migration in the form of diverging holes are not created during drilling.

2. Such other geophysical surveys and tests as are needed after taking into account the availability of similar data in the area of the drilling site, the construction plan, and the need for additional information that may arise as the construction of the well progresses. In determining which geophysical surveys and tests shall be required, the following geophysical surveys shall be considered for use in the following situations:

a. For surface casing intended to protect underground sources of drinking water a resistivity, sonic survey, gamma ray, spontaneous potential, and mechanical or sonar caliper surveys before the casing is installed, and a cement evaluation or temperature survey after the casing is set and cemented.

b. For intermediate and long strings of casing intended to facilitate injection a resistivity, spontaneous potential, porosity, fracture finder surveys and gamma ray surveys before the casing is installed, and a cement evaluation, temperature, or density survey after the casing is set and cemented.

c. For Class I wells in which an annular monitor tube is proposed for other than the final or innermost casing a caliper survey in the reamed hole which is to contain the monitor tube, and a temperature survey in the monitor tube after the monitor tube has been set and cemented.

(b) The following information concerning the injection formation shall be determined or calculated for new Class I wells:

1. Fluid pressure;

2. Temperature;

3. Fracture pressure;

4. Other physical and chemical characteristics of the injection matrix; and

5. Physical and chemical characteristics of the formation fluids.

(7) Testing of Completed Class I Wells.

Upon completion of construction, the completed wells shall be tested to assure that the wells will function as built. Tests to be performed include:

(a) Cement evaluation survey;

(b) Temperature survey;

(c) Pressure test of the final casing to at least 1.5 times the expected injection pressure or 50 pounds per square inch, whichever is greater, for one hour, with a change in pressure of no more than five percent from the initial test pressure;

(d) Video television survey – from top to bottom of the well for baseline monitoring purposes;

(e) Injection tests;

(f) Withdrawal tests – if necessary and if possible;

(g) Caliper survey; and

(h) Radioactive tracer survey.

(8) Testing of Class III Wells.

(a) Geophysical surveys and other tests shall be conducted during the drilling and construction of new Class III wells. Upon completion of construction, the completed well system shall be tested to assure that the well system will function properly at the designed operation pressures. A descriptive report interpreting the results of such surveys and tests shall be prepared and submitted to the Department. The surveys 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 as the construction of the well progresses. Such surveys and tests shall include deviation checks conducted on all holes where pilot holes and reaming are used, at sufficiently frequent intervals to assure that vertical avenues for fluid migration in the form of diverging holes are not created during drilling.

(b) Where the injection zone is a water bearing formation, the following information concerning the injection zone shall be determined or calculated for new Class III wells:

1. Fluid pressure;

2. Temperature;

3. Fracture pressure;

4. Other physical and chemical characteristics of the injection zone;

5. Physical and chemical characteristics of the formation fluids; and

6. Compatibility of injected fluids with formation fluids.

(c) Where the injection formation is not a water bearing formation, the information in subparagraphs (b)3. and (b)4. of this subsection shall be submitted.

(9) Environmental Concerns During Construction.

(a) For Class I and III wells, the disposal of drilling fluids or cuttings and the disposal of formation water or waste during testing shall be done in a sound environmental manner that avoids violation of surface and ground water quality standards. The applicant shall submit the proposed disposal methods with the permit application.

(b) For Class I wells the use of drilling pads is required. The pads shall be designed to collect spillage of contaminants and to support the heaviest load that will be encountered during drilling. At locations where the unconfined aquifer contains less than 10,000 mg/L total dissolved solids, monitor wells capable of detecting any contamination of the unconfined aquifer from drilling activities shall be required.

(c) For Class I wells, flow control shall be used when drilling into formations in which pressure heads exceed land surface, to prevent uncontrolled release of formation or drilling fluids at land surface.

(d) For Class III wells, the applicant is advised that other permits may be required for surface facilities associated with the mining activity.

Specific Authority 373.309, 403.061, 403.087 FS. Law Implemented 373.308, 403.021, 403.061, 403.062, 403.087 FS. History–New 4-1-82, Amended 5-8-85, Formerly 17-28.22, 17-28.220, 62-28.220, Amended 8-10-95, 6-24-97.