Tenn. Comp. R. & Regs. 0400-52-07-.01 - CASING REQUIREMENTS

(1) Surface Casing

(a) The operator shall set surface casing at 100 feet below the lowest known fresh water aquifer. The Supervisor shall have the authority to require distances of less than 100 feet upon specific request from the operator if adequate technical justification can be made. The operator shall use casing that has an external collapse pressure rating great enough to handle the hydrostatic pressure of a class A cement from the casing shoe to surface and internal pressure rating to handle any anticipated down hole pressures. The operator shall use cement with a minimum 500 psi compressive strength and will allow a minimum of 8 hour wait, or until the cement has adequately set, prior to drilling the shoe out. Surface casing shall be used to protect fresh water aquifers. No casing shoe shall be drilled until a cement seal has been brought back to the surface and secured between the surface casing and the well bore, preventing any ground water contamination.

(b) In non-Cumberland Plateau wells in areas of known lower pressures, the operator shall set all surface casing 100 feet below the fresh water. The Supervisor shall have the authority to require distances less than 100 feet upon specific request from the operator if adequate technical justification can be made. The operator shall use casing with an external collapse pressure rating great enough to handle the hydrostatic pressure of a class A cement from the casing shoe to surface. A Float shoe or Baffle or Guide shoe with Wiper Plug along with annular cement volume plus 35% excess shall be required on all surface casing cement jobs. Cement shall have a minimum 500 psi compressive strength and have a minimum 8 hour wait, or longer if needed to ensure that cement has adequately set, prior to drilling the shoe out. No casing shoe shall be drilled until a cement seal has been brought back to the surface and secured between the surface casing and the well bore, preventing any ground water contamination. The operator shall present all cement and casing designs on a specifications sheet with permit application for approval.

(2) If intermediate casing is used, the operator shall set an intermediate string of casing prior to drilling into any known oil and gas producing zone. Casing shall have a minimum internal pressure rating of 110% of maximum formation pressure reasonably expected based on the depth and location of the well. The operator shall cement the intermediate casing at a minimum of 100 feet into the surface casing. Casing string shall be deep enough to prevent underground blowout from anticipated bottomhole pressures. Casing shall have an external collapse pressure rating to handle cement design from casing shoe to surface. The operator shall use cement with 500 psi compressive strength and have a minimum 8 hour wait, or until cement has adequately set, prior to drilling the shoe out..

(3) The operator shall present all cement and casing designs on a specifications sheet with permit application for approval. A copy of cement tickets shall be kept on location to be viewed by the inspector until the drill rig is removed. In unknown or over pressured conditions a 5000 psi rating on casing shall apply. The operator shall attach a copy of all cement tickets to the well history tickets and shall include all volumes and pressures of job from start to finish. To ensure adequate annular space for cementing, the annular space outside the casing shall be at least as large as follows for the applicable casing size:

Up to 7" Outside Diameter (O.D.) Casing O.D. + 1 1/2"

More than 7" and less than 10 3/4" O.D. Casing O.D. + 2"

More than 10 3/4 "O.D. Casing O.D + 3"

(4) Any wells on the Cumberland Plateau drilled to depths above the Chattanooga Shale may be eligible for variances on the casing requirements in this rule by making a specific request to the Supervisor.

Notes

Tenn. Comp. R. & Regs. 0400-52-07-.01

Original rule filed March 20, 2013; effective June 18, 2013.

Authority: T.C.A §§ 60-1-201 et seq., and 4-5-201 et seq.