Wellbore Integrity and Protecting Groundwater FAQ DRAFT


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Denver, CO (Jun. 10, 2020) - 

Introduction:

SB 19-181 changed the COGCC’s mission from “fostering” oil and gas development, to “regulating” in a manner that is protective of public health, safety, welfare, wildlife, and the environment. SB 19-181 specifically instructed the COGCC to adopt new rules governing Wellbore Integrity rulemaking, because of the importance of wellbore integrity to protect Colorado’s groundwater from potential contamination from oil and gas activity.

What is the relationship between the COGCC, Wellbore Integrity and Protecting Groundwater?

Water is an essential and critical resource for our state and COGCC takes very seriously its role in protecting this resource, especially with Colorado’s growing reliance on groundwater due to increased demand from population and climate change. Activities throughout the lifecycle of oil and gas operations, from development, to production, to abandonment, have the potential to interface with groundwater. The wellbore, or oil/gas well, must be built and maintained in so that it isolates any fluids from interacting with groundwater, ever. That is why COGCC’s rulemaking regarding the protection of groundwater, with Wellbore Integrity, is so critical.

To understand how COGCC is protecting groundwater, we first need to understand wellbore integrity:

What are the terms “wellbore” and “well”?
WELL is a hole drilled into the ground to produce oil and gas.

WELLBORE broadly refers to the drilled hole and the casing, cement, drilling fluids, casing appurtenances, and fluids used to place the cement.

What is Wellbore Integrity?
Practices and standards to ensure that all downhole fluids stay within a wellbore as intended, and that no external fluids 

Why is Wellbore Integrity important?

Maintaining wellbore integrity ensures that oil and gas operations protect groundwater from potential contamination by isolating groundwater from other formations. Isolating fluids within the wellbore also prevents waste by ensuring that any oil and gas formations penetrated by the wellbore, but not targeted for production, do not enter the wellbore.

Operators maintain wellbore integrity by installing multiple layers of metal casing and cement to isolate the wellbore from the surrounding geological formations.

Another key aspect of maintaining wellbore integrity is regular monitoring and tests to ensure that unintended holes or leaks in the casing or cement that could contribute to flow do not exist or develop over time.

How does the COGCC ensure the protection of groundwater in oil & gas operations?

The COGCC’s wellbore integrity rules cover the life of the well - from design, to build, during development and production, until when the well is abandoned or plugged to prevent future production from that well.

Wellbore Integrity is designed to protect groundwater during all phases of oil and gas development, production, and closure.

Permitting Phase:

Permit (Form 2) Application to Drill​ - Operators submit a permit to drill that must include a detailed description of the planned wellbore location, and a detailed casing and cementing table that operators use to demonstrate how they will isolate groundwater and hydrocarbon formations and avoid other subsurface hazards by specifying the types of metal casing and cement that they will use throughout the depth of the well.
COGCC’s permitting and engineering units evaluate the operator’s permit to understand its design and how it will protect any groundwater resources, among other factors. This takes into account the location, proposed direction and pathway for the wellbore, and whether other nearby or “offset” wells could inadvertently provide a pathway for fluids to migrate.

In evaluating Form 2 applications, COGCC uses information about the location and quality of groundwater formations from the Colorado Division of Water Resources, the Colorado Water Quality Control Commission, the Colorado Geological Survey, and decades of the COGCC’s own experience in reviewing oil and gas wells drilled nearby. In the Denver-Julesburg Basin, COGCC staff have detailed data about groundwater formations from a variety of sources, including the Colorado Groundwater Atlas, baseline groundwater surveys, conductivity and resistivity logs, and consultation with other expert state agencies.

The COGCC has also created Field Scout Cards, which provide information about specific basins including a type log, a wellbore diagram which shows typical casing and cement designs for isolation, and geologic information. Additionally, they often have details about how wells should be plugged and if there is relevant historical construction information. COGCC uses these Field Scout Cards for some areas, including parts of the Piceance and North Park Basins, which have extensive information on the groundwater resources. 

Development Phase:

Once a permit to drill, or Form 2, has been approved, the operator may begin development of the oil and gas resource by drilling its wellbore. Because the permitting process has identified any and all water resources that may be affected during this process, operators must comply with site-specific casing and cementing requirements to protect these water resources.

Before stimulating (fracturing) a well, operators must perform a successful pressure test to ensure that production casing can withstand the pressures present during hydraulic fracturing. Operators must also perform successful pressure tests on surface equipment that will be exposed to hydraulic fracturing treatment.

Hydraulic Fracturing​, a type of well stimulation, occurs during the “development” or “completion”  phase. Operators must provide notice to owners of nearby oil and gas wells at least 90 days before hydraulically fracturing a well so that they can ensure the fracturing process will not cause inadvertent issues with their wells. During hydraulic fracturing (and other stimulation processes), operators must continuously monitor bradenhead pressure to ensure that the wellbore maintains integrity. If any issues arise, the operator must notify the Commission within 24 hours by submitting a Form 42, Notice of High Bradenhead Pressure During Stimulation.

After hydraulic fracturing is complete, the operator must submit a Form 5A to provide all important details about the hydraulic fracturing treatment, including fluid volumes involved. Operators are also required to complete the chemical disclosure registry form, this provides details about the hydraulic fracturing treatment and is published on FracFocus.org.

Production Phase:

As a well moves from development into production, when a well is capable of producing either separable gas or salable liquid hydrocarbons, the wellbore is subject to a series of regulated testing and monitoring to ensure that it is maintained and operating effectively by isolating all fluids within the wellbore and without allowing any fluids to commingle from outside of the wellbore.

The COGCC requires regular testing of the well, called Bradenhead Testing or monitoring, which observes the pressure of the well. It is the way to measure that the structure of the well is able to prevent any fluids or gasses from leaving the well or entering the well.

Bradenhead: What is Bradenhead testing? What is Bradenhead monitoring? How are these different? What is the purpose? How does it protect groundwater? 

  • What is the term “Bradenhead” ? Bradenhead refers to the empty space (also known as the annular space) between the surface casing and the next smaller diameter casing string that extends all the way up to the surface of the earth.
  • Another key aspect of maintaining wellbore integrity is regular monitoring and tests to ensure that unintended holes or leaks in the casing or cement that could contribute to flow do not exist or develop over time.
  • Bradenhead monitoring is one such method of verifying wellbore integrity. It is a valuable tool because changes in bradenhead pressure or fluid flow to the surface can be a key indicator of potential wellbore integrity issues.
  • Bradenhead monitoring, which involves reading pressure from surface equipment, is distinct from bradenhead testing, which requires opening the bradenhead and observing changes in pressure over time. The Commission’s Wellbore Integrity Rules require monthly bradenhead monitoring and annual bradenhead testing.

Closure or the Abandonment/ Plugging a Well Phase:

PLUGGING AND ABANDONMENT means the cementing of a well, the removal of its associated production facilities, the abandonment of its flowline(s), and the remediation and reclamation of the wellsite.

Once an operator has decided to plug and abandon a well, it will cease production of oil and gas. While this is the final phase of the oil and gas operation for a well, it is critical that it is done correctly to protect groundwater and ensure that the well will continue to uphold its integrity and not allow fluids to enter the groundwater from the wellbore.

The COGCC’s rules around plugging and abandoning a well mean that a Form 6, Notice of Intent to Abandon, is submitted, to signify that this well will be plugged and abandoned. COGCC staff reviews the proposed plugging design to ensure groundwater and hydrocarbon formations will be permanently isolated. Once plugging operations are complete, the Operator submits a Form 6, Subsequent Report of Abandonment to document and verify abandonment of the well.

Understanding COGCC’s Proposed Wellbore Integrity Rules & Protecting Groundwater FAQ 

Background
Because of the importance of wellbore integrity to protecting groundwater and preventing waste, the COGCC has long been concerned with ensuring that its Rules are adequate to preserve wellbore integrity.

The Wellbore Integrity Rules will implement:

  • SB 19-181’s directives to consider the recommendations of the 2019 SOGRE Report
  • The Commission’s statutory directive to:
    • Protect public health, safety, welfare, and the environment, by ensuring that groundwater will be isolated to prevent contamination by oil, gas, and produced water.
    • Prevent waste, by ensuring that hydrocarbons remain within the wellbore and reach production equipment and by protecting hydrocarbon formations not targeted for development from intermingling with non-native fluids.

What increased protections are being proposed with the SB 19-181 Wellbore Integrity rules? How will these further protect groundwater?  

The COGCC has proposed changes to permitting, construction, operation, and, abandonment or plugging of production wells; Changes for safety and environmental protections during drilling and hydraulic fracturing; and will require regular integrity assessments for all oil and gas production wells.

How do COGCC’s proposed WBI rules protect Colorado’s groundwater?

The COGCC’s Wellbore Integrity Rulemaking will bring increased protections to permitting, construction, operation and closure of production wells; safety and environmental protections during drilling and completion (hydraulic fracturing); and requiring regular assessments for all oil and gas production wells.

Consistent with SB 19-181’s directive to require regular integrity assessments, including surface monitoring, the proposed Rules update and codify the Commission’s current bradenhead monitoring and testing rules and guidance by establishing more frequent monitoring and tests statewide, setting standards for a successful test, and requiring immediate action to remedy failed tests.

Address the permitting, construction, operation and closure of production wells.

  • Permitting Phase:​ A number of the new and amended 300 Series Rules require or refer to groundwater isolation, which means the prevention of oil, gas, and water migration between formations. The groundwater isolation strategy for a proposed well is set forth in the casing and cementing plan in the Form 2, Application for Permit to Drill. The Commission Staff evaluates the proposed casing and cementing plan on a case-by-case basis to ensure that all wells have adequate casing and cementing to isolate groundwater and hydrocarbon formations. The Commission identifies where groundwater formations are located using numerous sources, including groundwater data available in the COGCC database and other Commission records, from the Colorado Division of Water Resources, the Colorado Water Quality Control Commission, and the Colorado Geological Survey.
  • Development & Construction Phase: ​ Under Rule 317, isolation can involve various casing and cementing strategies, such as surface casing that covers shallower formations that supply water wells and serves as the primary isolation from the produced fluids, and intermediate or production casing that isolates the productive formation from the remainder of the wellbore. Additional isolation is provided by covering the casing with cement at various points. In all wellbores, operators will fully cement the surface casing, and, if intermediate casing is used, operators will cement the intermediate casing above the producing formation. Operators will cement the production casing above or across the producing formation through groundwater that the WQCC has classified as being high-enough quality to be usable, now or in the future, and through unclassified groundwater with relatively low salinity. With the Director’s approval, where appropriate, operators will use alternative stage cement to cover intermediate formations.
  • Require that wells are constructed using current practices and standards that protect water zones and prevent blowouts;
    • Consistent with SB 19-181’s directive to address construction and operation of production wells, the Rules will strengthen standards for cementing and casing to ensure that wells withstand downhole pressures and maintain integrity throughout their life cycles.
    • Consistent with SB 19-181’s directive to require that wells are constructed using current practices and standards to prevent blowouts, the Rules update standards for using blowout preventer systems to incorporate current best practices and technology.
  • Enhance safety and environmental protections during operations such as drilling and hydraulic fracturing;
    • Consistent with SB 19-181’s directive to enhance safety and environmental protections during drilling and hydraulic fracturing operations, the Rules will codify requirements for evaluating offset wells to safeguard groundwater from potential contamination due to stimulation communication.
    • Well communication, sometimes known as “frack hits,” can potentially pose safety risks, and lead to groundwater or surface water contamination when one well’s stimulation process (typically hydraulic fracturing) “communicates with” (intersects or enters) an existing well. The rules will also expand existing requirements for real-time monitoring of wells during the hydraulic fracturing process.
  • Require regular integrity assessments for all oil and gas production wells, such as surface pressure monitoring during production
    • In addition, revised Rule 341 increases the frequency of bradenhead monitoring, which is an indicator of wellbore integrity. The Rules also adopt a new Formation Integrity Testing requirement to document surface casing integrity for well control and groundwater isolation from producing formations.

Groundwater Protection Partners: