Best Practices to Prevent or Mitigate Seismic Activity Caused by Humans
• Do not wait for seismic activity to start before taking action. Prepare the well and its operation as if seismic activity will become a problem.
• Use basic petroleum engineering practices and geology and geophysical information to provide a better understanding of the presence and nature of faults as part of site assessment. Evaluate all existing data from the region and locality to find active subsurface stresses and reservoir pathways.
• Determine the potential pressure buildup in any proposed storage disposal area underground.
• Fill in holes in the data with additional geoscience experts conducting whatever they consider to be appropriate studies.
• Measure the initial pressure at the bottom hole and determine if additional pressures will cause seismic activity.
• Review the data from operating wells in the area to determine the amount of pressure that is present, any informational flow behavior in the injection zone, and any reports of seismic activity. Where there have been suspected problems to frequent pressure tests, determine if higher pressure causes seismic activity.
• Inject wastewater intermittently instead of continuously to allow pressure buildup to be relieved.
• Separate multiple injection wells by substantial distances to allow pressure distribution.
• Increase monitoring where problems exist, so that pressure and quantity of injected material can be identified quickly and action can be taken to reduce them.
Best Practices for Class II Underground Injection Wells
• Requires a permit prior to construction from the proper authorizing agency including information on casing and cementing, financial assurances, maximum operating pressure to avoid causing or increasing fractures that would allow the fluids to enter the underground safe drinking water supply, monitoring and reporting requirements, demonstration of mechanical integrity, pressure test when the system has been disturbed, and appropriate plans for plugging and abandonment of the well.
• Use mechanical integrity tests at least once every 5 years for the Class II injection well. Advise the US EPA at least 30 days prior to the test.
• Use a review area which is a minimum of 0.25-mile radius from the well.
• Conduct monitoring of injection pressure, flow rate, and volume regularly and as needed on a continuous basis.
• Sample the injection fluid and determine if it meets the specifications established for the operation.
• Provide the appropriate authority with a record of plugging and abandonment of wells within 60 days of the operation.