Building directly over an old oil well is strongly discouraged due to significant safety, environmental, and access concerns, even if the well has been officially plugged and abandoned.
Why Building Over an Oil Well Is Not Recommended
While a well might appear dormant or be officially plugged, experts in geologic energy management universally advise against placing structures directly over them. This recommendation holds true even for wells abandoned to the most stringent industry standards. The primary reasons include:
1. Safety Hazards
Old oil wells, even those properly abandoned, can pose various safety risks:
- Gas Migration: Over time, the integrity of a well's plug can degrade, potentially allowing subsurface gases (like methane or hydrogen sulfide) to migrate to the surface. These gases can accumulate in enclosed spaces, leading to explosion hazards or asphyxiation.
- Subsidence: The ground around an abandoned wellbore might settle or collapse, creating sinkholes or instability that can damage foundations and structures.
- Fluid Leaks: Although rare, the possibility of residual oil, water, or other fluids leaking to the surface exists, leading to environmental contamination and health risks.
2. Regulatory Compliance and Access
Regulatory bodies oversee the abandonment and management of oil and gas wells. Their guidelines are crucial for public safety and environmental protection.
- Access Requirements: It is imperative that any construction does not obstruct access to wells. This applies not only to wells directly on the development property but also to those located off-site but near the development area. Unobstructed access is critical for future inspection, monitoring, potential re-abandonment, or addressing unforeseen issues.
- Building Code Restrictions: Many jurisdictions have specific building codes or zoning regulations that prohibit or severely restrict construction over or near abandoned oil wells. Failing to comply can lead to costly demolition, fines, and legal liabilities.
3. Long-Term Liabilities
Property owners who build over an old oil well may face long-term liabilities:
- Maintenance and Remediation: Should an issue arise with the well, such as gas leaks or subsidence, the property owner could be responsible for expensive remediation efforts.
- Property Value Impact: The presence of an abandoned well, especially one built over, can significantly complicate future property sales and potentially diminish property value due to perceived risks and disclosure requirements.
What to Do If You Discover an Old Oil Well
If you are planning development on land that may contain an old oil well, consider these crucial steps:
- Conduct a Thorough Site Assessment: Before any construction begins, engage environmental consultants and petroleum engineers to conduct a comprehensive site survey. This includes reviewing historical records, performing magnetic or geophysical surveys, and potentially drilling boreholes to locate any wells. Resources like state geological surveys or environmental protection agencies often provide databases or resources for identifying abandoned wells.
- Consult Regulatory Agencies: Contact your local or state regulatory agencies responsible for oil and gas operations. They can provide specific guidelines, permitting requirements, and information on known abandoned wells in the area.
- Consider Relocation or Mitigation: If a well is identified, explore options such as:
- Redesigning the project: Adjust the building footprint or development plan to avoid the well's location and maintain a safe setback distance.
- Well Re-abandonment: In some cases, agencies may require the well to be re-abandoned to modern standards, which involves rigorous sealing and monitoring.
- Protective Measures: Implement specific protective measures around the well, such as venting systems for gas or specialized foundations, though these are often less preferred than avoidance.
Summary of Considerations for Building Near Old Wells
| Consideration | Description | Potential Impact |
|---|---|---|
| Safety Risks | Gas migration, ground instability (subsidence), potential fluid leaks. | Explosion, asphyxiation, structural damage, environmental contamination, health risks. |
| Access Needs | Requirement for regulatory agencies to access wells for inspection, monitoring, or future work, even if outside property boundaries. | Regulatory non-compliance, inability to perform necessary well maintenance, legal issues. |
| Regulatory Rules | Specific local and state building codes, zoning laws, and oil/gas regulations prohibiting or restricting construction over or near wells. | Costly delays, demolition orders, fines, inability to obtain permits, legal liabilities. |
| Future Liability | Ongoing responsibility for well integrity, potential remediation costs if issues arise, negative impact on property value and salability. | Financial burden, diminished property value, difficulties in selling property. |
| Remediation Cost | The high cost associated with investigating, re-abandoning, or mitigating problems caused by an old well under a structure. | Significant unexpected expenses, project delays. |
Ultimately, avoiding construction over or immediately adjacent to old oil wells is the safest and most responsible approach to property development.
