Technical Review


This part of the permit review verifies that the proposed injection well meets construction and operation standards for groundwater protection and confinement of injected fluids. 

| Surface Casing Requirements| Cementing Requirements for Production Casing | Geological Requirements | Area of Review Requirements | Packer Requirements | Injection Pressure Requirements | Rule Exception Review | Injected Fluids | Requirements for Commercial Facilities | Requirements for Dual Completion Wells | Requirements for Horizontal Injection Wells | Requirements for Downhole Water Separation Wells | Requirements for Area Injection Permits | Engineering and Geological Studies |

Technical Staff contact information 

1.  Surface Casing Requirements - This part of the permit review verifies that groundwater is adequately protected. 

  • For new wells, surface casing must be set to the protection depth determined by the Groundwater Advisory Unit of the Railroad Commission of Texas and cemented to the surface. 

    NOTE: 

    Cementing the long-string casing from total depth to the surface instead of setting surface casing is not normally allowed.
  • Proposals to convert existing wells with short surface casing or single string completions will be considered on a case-by-case basis. They may be permitted for injection or disposal with additional safeguards such as remedial cementing, annual pressure testing, and/or annulus pressure monitoring. 
  • Technical discussion
2.  Cementing Requirements for Production Casing - This part of the permit review verifies that the production casing is adequately cemented to confine injected fluids to the proposed injection zone. 
  • The production casing must be cemented immediately above the injection/disposal zone with at least:
    • 500 feet of cement based on cement volume calculations if the well was spudded prior to January 1, 2014;
    • 600 feet of cement based on cement volume calculations if the well was spudded on or after January 1, 2014;
    • 250 feet of cement verified by a temperature survey conducted at the time of cementing; or
    • 100 feet of cement verified by a cement bond log that shows the cement is well bonded to the pipe and formation (80% bond or higher) with no indication of channeling.

    NOTE: 

    In verifying cement top calculations, our staff assumes Class A cement with no volume extenders unless the application indicates otherwise.  A washout factor is used in the calculations (30% along the Gulf Coast, and 20% inland).
  • In the absence of cementing records, the casing will be presumed to be un-cemented and the applicant will be required to file a cement bond log to demonstrate the adequacy of existing cement, or perform a cement squeeze. 

    NOTE: 

    Cement bond logs must contain a cement bond amplitude curve, an amplified cement bond curve, a transit/travel time curve, and a variable density/sonic waveform display.
  • Technical discussion
3.  Geological Requirements - This part of the permit review verifies that the proposed injection zone is adequately isolated by relatively impermeable strata to confine injected fluids to the proposed zone. 
  • The authorized injection or disposal strata must be isolated from overlying usable quality water by a sufficient thickness of relatively impermeable strata, which is generally considered to be an accumulative total of at least 250 feet of clay or shale.
  • For injection wells permitted under Rule 46, an exception may be made for injection into productive formations located near the base of usable quality water. In these cases, injection fluids are limited to waters produced from the productive formation and from wells on the same lease. 

    NOTE: 

    Both Rules 9 and 46, as well as the permit itself, require that injected fluids be confined to the authorized injection interval, which is the depth interval stated on the application and resulting permit.   

    The entire formation/reservoir is not authorized for injection unless the stipulated depth intervals correspond to the entire formation/reservoir.
4.  Area of Review Requirements - This part of the permit review verifies that all wells within the area of review are adequately plugged to ensure that injected fluids are confined to the proposed injection zone. 
  • All abandoned wells within a 1/4-mile radius must have been plugged in a manner that will prevent movement of fluids from one zone to another.
  • The applicant may show by calculation that a lesser area will be affected by pressure increases to justify using the lesser area in lieu of the 1/4-mile radius.   These calculations must be performed by. and bear the seal of a professional engineer registered in the State of Texas.
  • Shallow disposal in the Barnett Shale area (shallower than the Barnett Shale) of North central Texas is required to show that all wells within a 1/2-mile radius have been adequately plugged or cemented across the disposal interval and to perform reservoir pressure increase calculations because of bradenhead pressure buildup problems in the area.
  • Shallow disposal in the Barnet Shale area (shallower than the Barnett Shale) of North central Texas is further limited to 1/4 psi per foot of depth because of bradenhead pressure buildup problems in the area.
  • The Area of Review does not stop at the Texas state line. If the AOR extends into an adjoining state, UIC staff will require that the adjoining state UIC program staff be notified of the permit application.
  • A variance from the Area of Review requirements can be granted to a field or other area if an applicant can prove that the variance will not result in a material increase in the risk of fluid movement into groundwater or to the ground surface. This can be demonstrated by:
    • Showing that reservoir pressure is insufficient to raise fluids to groundwater;
    • Showing that geological conditions are present that preclude upward movement of fluids; or
    • Other compelling evidence.
  • Technical discussion
5.  Packer Requirements - This part of the permit review verifies that the proposed packer setting depth will ensure that injected fluids are confined to the proposed injection zone. 
  • Disposal wells permitted under Rule 9 (Form W-14) must have a packer set within 100 feet of the permitted disposal interval.
  • Injection/disposal wells permitted under Rule 46 (Form H-1) must have a packer set no higher than 200 feet below the known top of cement behind the production casing and at least 150 feet below the base of usable quality water. 

    NOTE: 

    If there are potentially permeable zones between the proposed packer setting depth and the proposed injection interval, the packer must be set below those zones or the application must be amended to include those zones in the proposed injection interval. As a practical matter, staff will direct applicants to specify a packer setting depth within 100 feet of the top of the permitted interval.
6.  Injection Pressure Requirements - This part of the permit review verifies that the proposed injection pressure does not exceed the formation fracture gradient and that the existing casing cement is adequate to ensure that injected fluids are confined to the proposed injection zone.
  • The permitted pressure will not exceed 1/2 psi per foot of depth to the top of the injection/disposal interval, unless the results of a fracture pressure step-rate test support a higher pressure.
  • Generally, the maximum surface injection pressure will be the pressure requested in the application or 1/2 psi per foot of depth to the top of the injection/disposal interval, whichever is less.
  • Shallow (2,000 feet or less) disposal along the Gulf coast is further limited to 1/4 psi per foot of depth because of low fracture gradients in the coastal sediments.
  • Shallow disposal in the Barnet Shale area (shallower than the Barnett Shale) of North central Texas is further limited to 1/4 psi per foot of depth because of bradenhead pressure buildup problems in the area.
  • Technical discussion
7.  Rule Exception Review - Exceptions to the rule specified standard construction only when the proposed completion maintains the safety factor for groundwater protection and confinement of injected fluids. 
  • Tubing and Packer Exceptions (which allows injection down casing) - An exception to the tubing and packer requirement can be considered for certain types of low-risk wells that exceed the rule specified well construction standard.   As a matter of administrative policy, a tubing and packer exception will be considered only if:
    • A conventional tubing and packer completion is not feasible.
    • Surface casing must be cemented through the entire zone of usable quality ground water, and production casing cemented from total depth to surface.   Both strings of casing have good mechanical integrity.   Casing that has failed an MIT does not count as one of the two strings cemented T.D. to surface until it is repaired and passes an H-5 pressure test.   Cement behind both strings of casing must meet cement quality requirements of Rule 13.
    • The well can operate at low injection pressure (500 psi or less) and low injection volume (500 bbls/day or less).
    • Wells that are approved for casing injection will be required to perform a casing pressure test against a temporary packer/plug to demonstrate mechanical Integrity of the long string casing at least annually.
  • Packer Depth Exceptions (allows packer to be farther uphole from injection zone) - An exception to the packer setting depth requirement can be considered only if confinement of injected fluids to the authorized injection zone can be ensured. General requirements:
    • Packer must be set opposite cemented casing, with adequate cement above the packer.
    • There must be at least 250 feet of clay/shale between the packer depth and B.U.Q.W.
    • There are no productive horizons or potential disposal zones between packer depth and injection zone.
    • There is no indication of casing leaks below packer.
    • The permit may be issued with an additional radioactive tracer survey requirement to demonstrate mechanical integrity of the casing between the packer and permit zone.

    NOTE: 

    The packer setting depth requirements of Statewide Rule 46 (Forms H-1 and H-1A) allows greater flexibility in packer setting depths. 

    The packer depth proposed in the application is reviewed for the presence of potential zones between the packer and permitted injection zone. If any potential zones are found, the packer depth will be rejected. In this case, the packer must be lowered or the permitted zone must be raised to include the potential zone. 

    Moving the packer uphole after the permit is issued will likely result in subsequent mechanical integrity tests being ruled inonclusive.
  • Pressure Observation Valve Exceptions 
    Rule 9 and 46 require that wells to be equipped with wellhead pressure observation valves on the tubing and each annulus. An exception to the observation valve requirement can be considered only if confinement of injected fluids to the authorized injection zone can be ensured. 

      General requirements:
    1. There are no overpressured formations in the area
    2. There are no bradenhead pressure problems in the area
    3. An exception is not required if the subject annulus is fully cemented to ground surface
    4. Exception approval requires more frequent mechanical integrity testing and/or monitoring.
8.  Injected Fluids - This part of the permit review verifies that the proposed injection fluids are Oil and Gas Exploration and Production wastes.  Only these wastes may be injected into wells under Railroad Commission jurisdiction. 
  • The permit will be limited to the injection of produced salt water unless the application specifically lists other fluids to be injected.  Injected fluids must be oil and gas exploration and production fluids.
  • If the application involves injection of fresh water, the applicant must show that there is no economically or technically feasible alternative to the use of fresh water as an injection fluid.

9.  Requirements for Commercial Facilities
  • Rules 9 and 46, define a "commercial well" is a well whose owner or operator receives compensation from others for the disposal of oil field fluids or oil and gas wastes that are wholly or partially trucked or hauled to the well, and the primary business purpose for the well is to provide these services for compensation.
  • Special surface facility provisions will be included in the permit for a commercial well.  These provisions include requirements for spill prevention and containment, pit permitting, and site security.
  • The Commission requires that the provisions set out below be included in commercial disposal well and fluid injection well permits.  These provisions are designed to prevent pollution from activities associated with the surface facilities. 

    SURFACE FACILITY REQUIREMENTS:

    • Prior to beginning operation, all collecting pits, skimming pits, or washout pits must be permitted under the requirements of Statewide Rule 8.
    • Prior to beginning operation, a catch basin constructed of concrete, steel, or fiberglass must be installed to catch oil and gas waste which may spill as a result of connecting and disconnecting hoses or other apparatus while transferring oil and gas waste from tank trucks to the disposal facility.
    • Prior to beginning operation, all fabricated waste storage and pretreatment facilities (tanks, separators, or flow lines) shall be constructed of steel, concrete, fiberglass, or other materials approved by the Assistant Director of Technical Permitting. These facilities must be maintained so as to prevent discharges of oil and gas waste.
    • Prior to beginning operation, dikes shall be placed around all waste storage, pretreatment, or disposal facilities.  The dikes shall be designed so as to be able to contain a volume equal to the maximum holding capacity of all such facilities. Any liquids or wastes that do accumulate in the containment area shall be removed within 24 hours and disposed of in an authorized disposal facility.  
    • Prior to beginning operation, the facility shall have security to prevent unauthorized access. Access shall be secured by a 24-hour attendant, a fence and locked gate when unattended, or a key-controlled access system. For a facility without a 24-hour attendant, fencing shall be required unless terrain or vegetation prevents truck access except through entrances with lockable gates.
    • Prior to beginning operation, each storage tank shall be equipped with a device (visual gauge or alarm) to alert drivers when each tank is within 130 barrels from being full.
    • If the facility will have staff on-site for periods of time necessitating bathroom accommodations, these accommodations must be designed, installed, and maintained by a person licensed to do so and the accommodations must comply with all applicable local, county, and State health regulations.

10.  Requirements for Dual Completion Wells
  • The permit application must clearly indicate that the well will be a dual completion and identify the production and injection zones. 

    NOTE: 

    Normal permit conditions do not allow any perforations outside the permitted injection interval.
  • Appropriate mechanical integrity testing and monitoring conditions will be added to the permit. 

    NOTE: 

    The most common mechanical integrity testing procedure, for productive perforations in the tubing/packer annulus, is as follows:
    1. Pull the tubing and packer string(s) from the well.
    2. Set a temporary plug within 100 feet of the injection perforations.
    3. Run a test packer on tubing and set it just below the productive perforations.
    4. Perform a standard H-5 pressure test of the casing between the test packer and temporary plug (above perforations).
    5. Reset the test packer just above the productive perforations.
    6. Perform a standard H-5 pressure test of the annulus to test the casing from the test packer to the wellhead.
    7. Pull the tubing, test packer, and temporary plug, and then reset the injection string.
    8. Perform a radioactive tracer survey through the injection string to demonstrate tubing integrity and packer seal.
    9. File the Pressure Test Reports (Forms H-5) for each of the three parts of the mechanical integrity test.

11.  Requirements for Horizontal Injection Wells
  1. Notification must indicate that the well includes a horizontal segment and must include a plat showing the direction and extent of the horizontal segment.
  2. The Area of Review will be a ¼ mile radius along the horizontal segment.
  3. Provide measured and true vertical depths on the application.
  4. Provide a wellbore sketch.
  5. Appropriate mechanical integrity testing and monitoring conditions may be added to the permit.
12.  Requirements for Downhole Water Separation Wells
  • The application must clearly indicate that produced water will be separated from the oil or gas downhole.
    • Include a detailed wellbore configuration showing the separation mechanism.
    • Include a proposed mechanical integrity testing and monitoring program.
  • Appropriate mechanical integrity testing and monitoring conditions will be added to the permit.
13.  Requirements for Area Injection Permits
  • File the area permit application with at least one well. The Form H-1 or cover letter must specify that this is an "area permit application"
  • Include the depth of usable quality groundwater in the area of the permit.
  • File a wellbore diagram for each type of existing well configuration in the area. Including:
    • Casing and liner information,
    • Packer setting depth,
    • Type and volume of cements used, and
    • Top of cement and how it was determined (calculated, bond log, etc.)
  • File a wellbore diagram for each type of well configuration for newly drilled wells. Including:
    • Casing and liner information,
    • Packer setting depth, and
    • A statement that the well will be cased and cemented in accordance with Rule 13.
  • Injected fluids to be injected, maximum daily injection volume, and maximum surface injection pressure for the permit area.
  • Perform an Area of review for the entire permit area, plus a ¼ mile perimeter around the boundary of the permit area.
  • Provide a map showing all wells to be converted, with each well keyed to the appropriate wellbore configuration diagram.
  • Notify each surface owner of record within the permit area, all offset operators around the permit area, the county clerk where the well is located, and the city clerk if any well is within city limits.
  • File application to add wells to an area permit at least 20 days prior to conversion and include the following:
    • well identification and, for newly drilled wells, location plat,
    • well configuration,
    • $200 filing fee, and
    • any additional requirements stipulated by the area permit.
  • Only wells that meet the construction standard set out in the area permit may be authorized under the area permit
  • Regular permitting procedures can be used for wells that don’t meet the area permit standard due to:
    • Different well construction;
    • Different operating conditions, injection pressure, volumes, fluids, zones; or
    • Unplugged or unknown status wells within the area of review.
14.  Engineering and Geological Studies
  • Engineering Analysis: the practice of Engineering is regulated by the Texas Occupations Code, Title 6, Chapter 1001.  Any Engineering analysis required for the permit application must be performed by a licensed Professional Engineer. Some examples are:
    • Pressure front calculations which are typically done in conjunction with the Area of Review process.
    • Closure cost estimates for pits associated with commercial disposal well operations under SWR 78
    • Check the Texas Board of Professional Engineers website for other situations requiring an Engineer seal.
  • Geological Analysis   The practice of Geology is regulated by the Texas Occupations Code, Title 6, Chapter 1002.  Any Geological analysis required for the permit application must be performed by a licensed Professional Geoscientist. Some examples are:
    • Well log formation correlation and analysis which are typically done in conjunction with the Area of Review process.
    • Well log interpretation for reservoir evaluation of geologic separation, effective thickness, etc.
    • Check the Texas Board of Professional Geoscientists website for other situations requiring a Geologist seal.



Last Updated: 3/23/2016 10:26:03 AM