(a) Applicability. Subsections (b) - (i), (k) - (n), and (r) of this section apply to Class I wells except for salt cavern disposal wells and those Class I wells authorized to inject only nonhazardous desalination concentrate or nonhazardous drinking water treatment residuals. For salt dome cavern disposal wells, only subsections (c), (e) - (i), (k) - (l), (n) - (p), and (r) of this section apply. For bedded salt cavern disposal wells, only subsections (e) - (h), (k) - (l), (n) - (o), and (q) - (r) of this section apply. For Class I wells authorized to inject only nonhazardous desalination concentrate or nonhazardous drinking water treatment residuals, only subsections (e) - (h), (n), and (r) of this section apply.
(b) For Class I wells, prior to closing the well, the owner or operator shall observe and record the pressure decay for a time specified by the executive director. The executive director shall analyze the pressure decay and the transient pressure observations conducted pursuant to §331.64 of this title (relating to Monitoring and Testing Requirements) and determine whether the injection activity has conformed with predicted values.
(c) For Class I wells, prior to well closure, appropriate mechanical integrity testing shall be conducted to ensure the integrity of that portion of the long string casing and cement that will be left in the ground after closure. Testing methods may include:
  (1) pressure tests with liquid or gas;
  (2) radioactive tracer surveys for wells other than salt cavern disposal wells;
  (3) noise logs, temperature logs, pipe evaluation logs, cement bond logs, or oxygen activation logs; and
  (4) any other test required by the executive director.
(d) For Class I wells, prior to well closure the well shall be flushed with a nonhazardous buffer fluid.
(e) In closure of all Class I wells, Class III wells, and permitted Class V wells, a well shall be plugged in a manner which will not allow the movement of fluids through the well, out of the injection zone either into or between underground sources of drinking waters (USDWs) or to the land surface. Well plugs shall consist of cement or other materials that provide protection equivalent to or greater than that provided by cement.
(f) The permittee shall notify the executive director before commencing closure according to an approved plan. For Class I wells this notice shall be given at least 60 days before commencement. At the discretion of the executive director, a shorter notice period may be allowed. The executive director shall review any revised, updated, or additional closure plans.
(g) Placement of the plugs in the wellbore shall be accomplished by an approved method that may include one of the following:
  (1) the balance plug method;
  (2) the dump bailer method;
  (3) the two-plug method; or
  (4) an alternate method, approved by the executive director, that will reliably provide a comparable level of protection.
(h) Prior to closure, the well shall be in a state of static equilibrium with the mud or nonhazardous fluid weight equalized top to bottom, either by circulating the mud or fluid in the well at least once or by a comparable method prescribed by the executive director.
(i) Each plug used shall be appropriately tagged and tested for seal and stability before closure is completed.
(j) The closure plan shall, in the case of a Class III production zone which underlies or is in an exempted aquifer, also demonstrate that no movement of contaminants that will cause pollution from the production zone into a USDW or freshwater aquifer will occur. The commission shall prescribe aquifer cleanup and monitoring where deemed necessary and feasible to ensure that no migration of contaminants that will cause pollution from the production zone into a USDW or freshwater aquifer will occur.
(k) The following shall be considered in determining the adequacy of a plugging and abandonment plan for Class I and III 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 or economic conditions;
  (8) the amount, size, and location by depth of casings and any other materials left in the well;
  (9) the method and location where casing is to be parted if applicable;
  (10) the estimated cost of the plugging procedure; and
  (11) such other factors that may affect the adequacy of the plan.
(l) For Class I wells only, a monument or other permanent marker shall be placed at or attached to the plugged well before abandonment. The monument shall state the permit number, date of abandonment, and company name.
(m) Each owner of a Class I hazardous waste injection well, and the owner of the surface or subsurface property on or in which a Class I hazardous waste injection well is located, must record, within 60 days after approval by the executive director of the closure operations, a notation on the deed to the facility property or on some other instrument which is normally examined during a title search that will, in perpetuity, provide any potential purchaser of the property the following information:
  (1) the fact that land has been used to manage hazardous waste;
  (2) the name of the state agency or local authority with which the plat was filed, as well as the Austin address of the Underground Injection Control staff of the commission, to which it was submitted; and
  (3) the type and volume of waste injected, the injection interval or intervals, and for salt cavern wells, the maximum cavern radius into which it was injected, and the period over which injection occurred.
(n) Within 30 days after completion of closure, the permittee shall file with the executive director a closure report on forms provided by the commission. The report shall be certified as accurate by the owner or operator and by the person who performed the closure operation (if other than the owner or operator). This report shall consist of a statement that the well was closed in accordance with the closure plan previously submitted and approved by the executive director. Where the actual closure differed from the plan previously submitted, a written statement shall be submitted specifying the differences between the previous plan and the actual closure.
(o) For salt cavern disposal wells, prior to sealing the cavern and plugging the well, the owner or operator shall complete any pre-closure monitoring of the cavern and its contents required by rule or permit.
(p) For salt dome cavern disposal wells, the cavern shall be closed according to §331.170 of this title (relating to Cavern Closure).
(q) For bedded salt cavern disposal wells, the cavern shall be closed according to §331.250 of this title (relating to Bedded Salt Cavern Closure).
(r) The obligation to implement the closure plan survives the termination of a permit or the cessation of injection activities. The requirement to maintain and implement an approved plan is directly enforceable regardless of whether the closure plan requirement is a condition of the permit.

Source Note: The provisions of this §331.46 adopted to be effective May 13, 1986, 11 TexReg 1982; amended to be effective July 5, 1989, 14 TexReg 3047; amended to be effective June 22, 1992, 17 TexReg 4097; amended to be effective April 28, 1997, 22 TexReg 3526; amended to be effective November 23, 2000, 25 TexReg 11433; amended to be effective July 10, 2008, 33 TexReg 5342; amended to be effective March 12, 2009, 34 TexReg 1638; amended to be effective August 16, 2012, 37 TexReg 6078