Regulation, environment and well abandonment

Among Prairie Crest's 160 wells at Tamarack Lake field, about two dozen no longer produce enough to pay their costs. Each still has a wellhead, a pad, a road and pipeline connections, and each is a liability: it must eventually be plugged, its equipment removed and the land returned to ranching or farming. the Industrial Commission requires every operator to post a bond and to plug wells that have been inactive too long. Ethan has been asked to plan the coming year's plugging program. This lesson covers how oil and gas are regulated, how environmental risks are managed and how wells are retired.

Who regulates oil and gas

In the United States, oil and gas on private and state land is regulated mainly by the states. In North Dakota, North Dakota Industrial Commission (NDIC) oversees drilling, production, spacing, flaring and plugging through its Department of Mineral Resources, Oil and Gas Division, which issues permits, inspects sites and enforces state rules. The state health and environmental quality agency regulates air and water permits. Federal agencies play large roles too: the Environmental Protection Agency sets air emission standards under the Clean Air Act, the Bureau of Land Management regulates drilling on federal minerals, the Bureau of Indian Affairs and tribal governments oversee development on tribal land, and the Pipeline and Hazardous Materials Safety Administration regulates pipeline safety.

Regulators pursue several goals at once: safety of workers and the public, protection of the environment, conservation of resources by preventing waste, fairness among owners of a shared reservoir, and orderly development. Spacing rules, for example, limit how close wells can be to each other and to the boundaries of a lease, so that one owner does not drain a neighbor's oil. Pooling rules let owners combine their interests in a spacing unit so that a single well can be drilled and the revenue shared.

Environmental protection during operations

Every stage of a well's life carries environmental risks. Drilling and completion use large volumes of water and generate cuttings, spent fluids and flowback that must be handled and disposed of properly. Production facilities can leak oil, produced water and gas. Methane, the main component of natural gas, is a potent greenhouse gas, roughly 80 times stronger than carbon dioxide over twenty years, so leaks and venting from wells, tanks, compressors and pneumatic devices are a major climate concern. Flaring converts methane to carbon dioxide but still emits greenhouse gases and soot. Roads, pads and pipelines fragment habitat, and noise and traffic affect neighbors.

Operators manage these risks through design, monitoring and response. Well integrity, from cement and casing to wellhead seals, keeps fluids in the wellbore. Leak detection and repair programs use optical gas imaging cameras and other sensors to find and fix leaks. Secondary containment, such as lined berms around tanks, catches spills. Pipelines carry corrosion protection and are patrolled and inspected. Emergency response plans set out who does what if something goes wrong, and wells that may produce hydrogen sulfide need emergency planning zones and consultation with nearby residents.

Climate policy is a moving target. The EPA's 2024 standards for new and existing oil and gas sources, known by their regulation numbers OOOOb and OOOOc, require leak detection, near-zero venting from new pneumatic controllers, limits on routine flaring and controls on storage tanks. In 2025 the EPA began reconsidering them and extended many compliance deadlines to January 2027, and states are preparing their own plans for existing sources. Congress repealed the related federal waste emissions charge on methane in 2025. Engineers must follow the requirements in force on the day they design or operate a facility, which can change from year to year.

Inactive wells and liability

When a well stops producing, the company has three choices. It can try to revive it with a workover, a new zone or a waterflood. It can suspend it, securing it with plugs or valves so that it is safe while waiting for a decision. Or it can abandon it permanently. Suspension cannot last forever: a suspended well still has steel and cement that age, and a company can go bankrupt and leave its wells behind. Regulators therefore require companies to show that they can pay for closure and push them to close inactive wells within a reasonable time.

Across the United States, hundreds of thousands of old wells were left unplugged by owners who disappeared long ago. The 2021 Infrastructure Investment and Jobs Act set aside 4.7 billion dollars for plugging orphaned wells and reclaiming their sites, and North Dakota was one of the first states to use its grants. North Dakota requires operators to post bonds before drilling, which the state can use if an operator defaults, and it maintains a fund, paid for by industry, to plug abandoned wells and reclaim sites. Wells that have been inactive beyond the period allowed by state rules must be returned to production, placed in approved temporarily abandoned status or plugged.

# Closure liability for an example inventory and how long it takes to clear

def liability(n_wells, abandon_each, reclaim_each, facilities):
    return n_wells * (abandon_each + reclaim_each) + facilities

L = liability(32, 85000, 45000, 600000)
print(f"Closure liability today: {L / 1e6:.2f} million dollars")

spend = 1.2e6                 # dollars per year
new_inactive = 4              # wells that go inactive each year
cost_per_well = 85000 + 45000
growth = new_inactive * cost_per_well
print(f"Spending {spend / 1e6:.1f} M$/yr; new inactive wells add {growth / 1e6:.2f} M$/yr")

for annual_spend in (1.2e6, 1.6e6, 2.0e6):
    remaining, years = L, 0
    while remaining > 0 and years < 50:
        remaining += growth - annual_spend
        years += 1
    status = f"cleared in {years} years" if remaining <= 0 else "never cleared at this rate"
    print(f"  at {annual_spend / 1e6:.1f} M$/yr: {status}")

# Present value of the liability if it is paid evenly over 5 years at 10 %
pv = sum((L / 5) / 1.10 ** t for t in range(1, 6))
print(f"Present value of paying {L / 1e6:.2f} M$ over 5 years at 10 %: {pv / 1e6:.2f} M$")

Closure liability today: 4.76 million dollars
Spending 1.2 M$/yr; new inactive wells add 0.52 M$/yr
  at 1.2 M$/yr: cleared in 7 years
  at 1.6 M$/yr: cleared in 5 years
  at 2.0 M$/yr: cleared in 4 years
Present value of paying 4.76 M$ over 5 years at 10 %: 3.61 M$

How a well is abandoned

Abandoning a well means sealing it permanently so that no fluid can move between formations or reach the surface or groundwater, ever. The crew pulls the tubing, rods or pump, and tests whether gas is leaking up the outside of the casing, which would have to be repaired first. They then set cement plugs or mechanical bridge plugs capped with cement across every producing zone, any zone with fluids that could flow and the base of groundwater protection. Each plug is tagged or pressure-tested to prove it is in place. Finally, the casing is cut off below ground level, a steel cap is welded on or a vented cap is installed as the rules require, and the hole is backfilled.

In North Dakota, state rules set the requirements for plugging, including notice to the Industrial Commission before work starts, the placement of cement plugs across producing zones and the base of fresh water, and cutting off the casing several feet below the surface. A state inspector may witness the work. After plugging, the operator removes equipment and gravel, replaces topsoil, recontours the site and reseeds it, and the surface owner may sign off on the reclamation. The operator's bond is released only when the state is satisfied the well is plugged and the site reclaimed.

Closure costs vary widely. Shallow, simple wells may cost tens of thousands of dollars to abandon; deep wells, wells with gas migration or casing leaks, and sour wells can cost many times more. Grouping wells by area, sharing rigs and crews among companies and planning work in good weather all reduce costs. Some operators now design wells from the start for easier abandonment, with better cement and corrosion-resistant materials, and some explore reusing old wells for geothermal energy or monitoring.

Spills, incidents and reporting

Even well-run operations have incidents, and the regulator expects them to be reported quickly, contained and cleaned up. A release of oil or produced water must be reported once it exceeds a threshold volume or reaches a water body, and the company must stop the source, contain the spill, recover what it can and remediate the soil to the applicable standard. Gas releases, fires, well control events and serious injuries also trigger reporting. Regulators investigate significant incidents, publish findings and may order changes across the industry, as happened after pipeline failures and well blowouts in the past.

Enforcement ranges from warnings and orders to fix a problem, through administrative penalties, to prosecution in court for serious or repeated violations. Regulators also use compliance assurance programs, inspections targeted at the highest-risk sites and public reporting of company performance. For engineers, the practical lesson is that compliance is designed in: a facility that meets the rules on the day it starts up, and is maintained properly, rarely produces an enforcement problem. Engineers who discover a safety or environmental problem have a professional duty to report it, even when it is inconvenient for the employer.

Data transparency has grown. Much of the information about wells, production, spills and inspections is now public, searchable by landowners, researchers and journalists. That openness puts pressure on operators to perform well, and it gives engineers a valuable source of data about offset wells, past incidents and the practices that work.

Landowners and nearby communities are part of the regulatory picture too. Companies notify and consult residents before drilling, compensate surface owners for the land they use and respond to complaints about noise, dust, odors and traffic. Good relations reduce objections at hearings and make it easier to develop the next wells, so many operators assign staff to community liaison full time.