SECTION 331.64. Monitoring and Testing Requirements

(a) Applicability. Subsections (b) - (j) of this section apply to all Class I wells except for those Class I wells authorized to inject only nonhazardous desalination concentrate or nonhazardous drinking water treatment residuals.

(b) Injection fluids shall be sampled and analyzed with a frequency sufficient to yield representative data of their characteristics.

(1) The owner or operator shall develop and follow an approved written waste analysis plan that describes the procedures to be carried out to obtain a detailed chemical and physical analysis of a representative sample of the waste, including the quality assurance procedures used. At a minimum, the plan shall specify:

(A) the parameters for which the waste will be analyzed and the rationale for the selection of these parameters;

(B) the test methods that will be used to test for these parameters; and

(C) the sampling method that will be used to obtain a representative sample of the waste to be analyzed.

(2) The owner or operator shall repeat the analysis of the injected wastes as described in the waste analysis plan and when process or operating changes occur that may significantly alter the characteristics of the waste stream.

(3) The owner or operator shall conduct continuous or periodic monitoring of selected parameters as required by the executive director.

(4) The owner or operator shall assure that the plan remains accurate and the analyses remain representative.

(c) Pressure gauges shall be installed and maintained, at the wellhead, in proper operating conditions at all times on the injection tubing and on the annulus between the tubing and long-string casing, and/or annulus between the tubing and liner.

(d) Continuous recording devices shall be installed, used, and maintained in proper operating condition at all times to record injection tubing pressures, injection flow rates, injection fluid temperatures, injection volumes, tubing-long string casing annulus pressure and volume, and any other data specified by the permit. The instruments shall be housed in weatherproof enclosures. The owner or operator shall also install and use:

(1) automatic alarm and automatic shutoff systems, designed to sound and shut-in the well when pressures and flow rates or other parameters approved by the executive director exceed a range and/or gradient specified in the permit; or

(2) automatic alarms designed to sound when the pressures and flow rates or other parameters approved by the executive director exceed a rate and/or gradient specified in the permit, in cases where the owner or operator certifies that a trained operator will be on location and able to immediately respond to alarms at all times when the well is operating.

(3) If an automatic alarm or shutdown is triggered, the owner or operator shall immediately investigate as expeditiously as possible the cause of the alarm or shutoff. If, upon investigation, the well appears to be lacking mechanical integrity, or if monitoring otherwise indicates that the well may be lacking mechanical integrity, the owner or operator shall:

(A) cease injection of waste fluids unless authorized by the executive director to continue or resume injection;

(B) take all necessary steps to determine the presence or absence of a leak; and

(C) notify the executive director within 24 hours after the alarm or shutdown.

(4) If the loss of mechanical integrity is discovered by monitoring or during periodic mechanical integrity testing, the owner or operator shall:

(A) immediately cease injection of waste fluids;

(B) take all steps reasonably necessary to determine whether there may have been a release of hazardous wastes or hazardous waste constituents into any unauthorized zone;

(C) notify the executive director within 24 hours after the loss of mechanical integrity is discovered;

(D) notify the executive director when injection can be expected to resume; and

(E) restore and demonstrate mechanical integrity to the satisfaction of the executive director prior to resuming injection of waste fluids.

(5) Whenever the owner or operator obtains evidence that there may have been a release of injected wastes into an unauthorized zone:

(A) the owner or operator shall immediately cease injection of waste fluids; and

(i) notify the executive director within 24 hours of obtaining such evidence;

(ii) take all necessary steps to identify and characterize the extent of any release;

(iii) propose a remediation plan for executive director review and approval;

(iv) comply with any remediation plan specified by the executive director;

(v) implement any remediation plan approved by the executive director; and

(vi) where such release is into an underground source of drinking water (USDW) or freshwater aquifer currently serving as a water supply, within 24 hours, notify the local health authority, place a notice in a newspaper of general circulation, and send notification by mail to adjacent landowners;

(B) the executive director may allow the operator to resume injection prior to completing cleanup action if the owner or operator demonstrates that the injection operation will not endanger USDWs or freshwater aquifers.

(e) Mechanical integrity testing.

(1) The integrity of the long string casing, injection tube, and annular seal shall be tested annually by means of an approved pressure test with a liquid or gas and whenever there has been a well workover. The integrity of the bottom-hole cement shall be tested annually by means of an approved radioactive tracer survey. A radioactive tracer survey may be required after workovers that have the potential to damage the cement within the injection zone.

(2) A temperature log, noise log, oxygen activation log, or other approved log shall be required by the executive director at least once every five years to test for fluid movement along the borehole.

(3) A casing inspection, casing evaluation, or other approved log shall be run whenever the owner or operator conducts a workover in which the injection string is pulled, unless the executive director waives this requirement due to well construction or other factors which limit the test's reliability, or based upon the satisfactory results of a casing inspection log run within the previous five years. The executive director may require that a casing inspection log be run every five years, if there is sufficient reason to believe the integrity of the long string casing of the well may be adversely affected by naturally occurring or man-made events.

(4) The executive director may allow the use of a test to demonstrate mechanical integrity other than those listed in paragraph (1) of this subsection with the written approval of the administrator of the United States Environmental Protection Agency (EPA) or his authorized representative. To obtain approval, the executive director shall submit a written request to the EPA administrator, which shall set forth the proposed test and all technical data supporting its use. The EPA administrator shall approve the request if it will reliably demonstrate the mechanical integrity of wells for which its use is proposed. Any alternate method approved by the EPA administrator shall be published in the Federal Register and may be used unless its use is restricted at the time of approval by the EPA administrator.

(f) Any wells within the area of review selected for the observation of water quality, formation pressure, or any other parameter, shall be monitored at a frequency sufficient to protect USDWs and fresh or surface water.

(g) Corrosion monitoring.

(1) Corrosion monitoring of well materials shall be conducted quarterly. Test materials shall be the same as those used in the injection tubing, packer, and long string casing, and shall be continuously exposed to the waste fluids with the exception of when the well is taken out of service. The owner or operator shall demonstrate that the waste stream will be compatible with the well materials with which the waste is expected to come into contact, and to submit to the executive director a description of the methodology used to make that determination. Compatibility for purposes of this requirement is established if contact with injected fluids will not cause the well materials to fail to satisfy any design requirement imposed under §331.62(a)(1) of this title (relating to Construction Standards). Testing shall be by:

(A) placing coupons of the well construction materials in contact with the waste stream; or

(B) routing the waste stream through a loop constructed with the material used in the well; or

(C) using an alternative method approved by the executive director.

(2) The test shall use materials identical to those used in the construction of the well, and those materials must be continuously exposed to the operating pressures and temperatures (measured at the wellhead) and flow rates of the injection operation; and

(3) The owner or operator shall monitor the materials for loss of mass, thickness, cracking, pitting and other signs of corrosion on a quarterly basis to ensure that the well components meet the minimum standards for material strength and performance set forth in §331.62(a)(1) of this title.

(4) Corrosion monitoring may be waived by the executive director if the injection well owner or operator satisfactorily demonstrates, before authorization to conduct injection operations, that the waste streams will not be corrosive to the well materials with which the waste is expected to come into contact throughout the life of the well. The demonstration shall include a description of the methodology used to make that determination.

(h) Ambient monitoring.

(1) Based on a site-specific assessment of the potential for fluid movement from the well or injection zone and on the potential value of monitoring wells to detect fluid movement, the executive director shall require the owner or operator to develop a monitoring program. When prescribing a monitoring system, the executive director may also require:

(A) Continuous monitoring for pressure changes in the first aquifer overlying the confining zone. When a monitor well is installed, the owner or operator shall, on a quarterly basis, sample the aquifer and analyze for constituents specified by the executive director;

(B) the use of indirect, geophysical techniques to determine the position of the waste front, the water quality in a formation designated by the executive director, or to provide other site-specific data;

(C) periodic monitoring of the ground water quality in the first aquifer overlying the injection zone;

(D) periodic monitoring of the ground water quality in the lowermost USDW; and

(E) any additional monitoring necessary to determine whether fluids are moving into or between USDWs.

(2) The pressure buildup in the injection zone shall be monitored annually, including at a minimum, a shut down of the well for a time sufficient to conduct a valid observation of the pressure fall-off curve.

(i) Any other monitoring and testing requirements which the executive director determines to be necessary including, but not limited to, monitoring for seismic activity.

(j) The owner or operator shall submit information demonstrating to the satisfaction of the executive director that the waste stream and its anticipated reaction products will not alter the permeability, thickness, or other relevant characteristics of the confining or injection zones such that they would no longer meet the requirements specified in §331.121(c) of this title (relating to Class I Wells).

(k) Class I Wells authorized to inject only nonhazardous desalination concentrate or nonhazardous drinking water treatment residuals shall comply with the following monitoring and testing requirements:

(1) Monitoring requirements. Monitoring requirements shall, at a minimum, include:

(A) The analysis of the injected fluids with sufficient frequency to yield representative data of their characteristics;

(B) Installation and use of continuous recording devices to monitor injection pressure, flow rate and volume, and the pressure on the annulus between the tubing and the long string of casing;

(C) Installation and use of monitoring wells within the area of review if required by the executive director, to monitor any migration of fluids into and pressure in the USDW. The type, number and location of the wells, the parameters to be measured, and the frequency of monitoring must be approved by the executive director;

(D) A demonstration of mechanical integrity pursuant to paragraph (4) of this subsection at least once every five years during the life of the well; and

(E) 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.

(2) When the executive director determines that an injection well lacks mechanical integrity pursuant to paragraph (4) of this subsection, the executive director shall give written notice of his determination to the owner or operator. Unless the executive director requires immediate cessation, the owner or operator shall cease injection into the well within 48 hours of receipt of the executive director's determination. The executive director may allow plugging of the well in accordance with the requirements of §331.46 of this title (relating to Closure Standards) or require the owner or operator to perform such additional construction, operation, monitoring, reporting and corrective action as is necessary to prevent the movement of fluid into or between USDWs caused by the lack of mechanical integrity. The owner or operator may resume injection upon receipt of written notification from the executive director that the owner or operator has demonstrated mechanical integrity under paragraph (4) of this subsection.

(3) The executive director may allow the owner or operator of a well which lacks mechanical integrity under paragraph (4) of this subsection to continue or resume injection if the owner or operator has made a satisfactory demonstration that there is no movement of fluid into or between USDWs.

(4) Mechanical Integrity Testing. An injection well has mechanical integrity if:

(A) There is no significant leak in the casing, tubing or packer; and

(B) There is no significant fluid movement into an USDW through vertical channels adjacent to the injection well bore.

(5) One of the following methods shall be used to evaluate the absence of significant leaks under paragraph (4)(A) of this subsection:

(A) Following an initial pressure test, monitoring of the tubing-casing annulus pressure with sufficient frequency to be representative, as determined by the executive director, while maintaining an annulus pressure different from atmospheric pressure measured at the surface; or

(B) Pressure test with liquid or gas.

(6) The results of a temperature or noise log must be used to determine the absence of significant fluid movement under paragraph (4)(B) of this subsection.

(7) The executive director may allow the use of a test to demonstrate mechanical integrity other than those listed in paragraph (5)(A) and (B) of this subsection with the written approval of the executive director. To obtain approval, the permittee shall submit a written request to the executive director, which shall set forth the proposed test and all technical data supporting its use. The executive director shall approve the request if it will reliably demonstrate the mechanical integrity of wells for which its use is proposed.

(8) In conducting and evaluating the tests enumerated in this section or others to be allowed by the executive director, the owner or operator and the executive director shall apply methods and standards generally accepted in the industry. When the owner or operator reports the results of mechanical integrity tests to the executive director, he shall include a description of the test(s) and the method(s) used. In making his evaluation, the executive director shall review monitoring and other test data submitted since the previous evaluation.

(9) The executive director may require additional or alternative tests if the results presented by the owner or operator under §331.64(k)(5) of this title (relating to Monitoring and Testing Requirements) are not satisfactory to the executive director to demonstrate that there is no movement of fluid into or between USDWs resulting from the injection activity.

(10) Ambient monitoring.

(A) Based on a site-specific assessment of the potential for fluid movement from the well or injection zone and on the potential value of monitoring wells to detect such movement, the executive director shall require the owner or operator to develop a monitoring program. At a minimum, the executive director shall require monitoring of the pressure buildup in the injection zone annually, including a shut down of the well for a time sufficient to conduct a valid observation of the pressure fall-off curve.

(B) When prescribing a monitoring system the executive director may also require:

(i) Continuous monitoring for pressure changes in the first aquifer overlying the confining zone. When such a well is installed, the owner or operator shall, on a quarterly basis, sample the aquifer and analyze for constituents specified by the executive director;

(ii) The use of indirect, geophysical techniques to determine the position of the waste front, the water quality in a formation designated by the executive director, or to provide other site-specific data;

(iii) Periodic monitoring of the ground water quality in the first aquifer overlying the injection zone;

(iv) Periodic monitoring of the ground water quality in the lowermost USDW; and

(v) Any additional monitoring necessary to determine whether fluids are moving into or between USDWs.

Source Note: The provisions of this §331.64 adopted to be effective May 13, 1986, 11 TexReg 1983; amended to be effective July 5, 1989, 14 TexReg 3047; amended to be effective January 2, 1995, 19 TexReg 10099; amended to be effective April 28, 1997, 22 TexReg 3526; amended to be effective July 10, 2008, 33 TexReg 5342; amended to be effective January 7, 2021, 46 TexReg 191