CLASS V Agricultural Drainage Well
Class I Injection Well
Deep well disposal of selected commercial/industrial wastes is a technically sound process which involves injecting liquid wastes into a deep underground formation (injection zone) using a well specifically constructed for that purpose. Typically injection zones are at depths of one quarter to one mile below the surface and are separated from sources of drinking water by impermeable over-lying rock formations (confining layers) that are hundreds of feet thick.
Injection zones used for commercial/industrial waste disposal characteristically contain saltwater and no potentially usable resources such as drinking water. The wastes are pumped into, and occupy, pore space within the injection zone. Properly located, constructed, operated, and monitored deep wells are designed to permanently isolate and contain injected waste within this zone.
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Class IV wells related to Hazardous and Radioactive Wastewater are banned and a threat to human health and environment requiring immediate closure and remediation if found.
Source: USEPA, Underground Injection Practices Council (UIPC)
MES Injection well construction
“Confining layers” Between Usable Sources of Drinking Water (USDW) and injection depth.
Loads Accepted By:
- Tanker Truck
- Flatbed Truck (Drums and Totes)
- Rail Car
Profile Forms:
NHIW Certification Form 
Waste Profile
At the Mid-Way Commercial NHIW Processing and Class I Disposal Well facility, liquid wastes are analyzed and undergo an approval process before they can be sent to the facility. Once approved, liquid wastes received from clients are analyzed again on-site, accepted and stored in a combination of above-ground tanks, in-ground tanks or a geomembrane lined basin. All tanks at this facility are within a secondary containment system to prevent release to the environment in the event of a catastrophic failure. After analysis, processing and filtering, solid removed from the liquids are dewatered and disposed at a permitted landfill facility while the liquid wastes are disposed through the on-site permitted Class I injection well. The liquid wastes are injected over 1 mile below the ground level into the Arbuckle Formation. The Arbuckle Formation is a porous sandstone formation that is overlain by numerous major impermeable confining layers which prevent migration of wastes towards the surface thereby posing an extremely low risk to people, animals, plants and drinking water aquifers.
The Mid-Way facility implements the latest technologies to provide liquid storage, transfer and underground injection. Components of the processing facility and the injection well are continuously monitored by computer systems and facility personnel to ensure the safest operation and compliance with the facility permits and all local, state and federal USEPA requirements. In the event that the system components deviate from the established safety protocols or permit requirements, automatic shutdown procedures are initiated until the situation can be accessed. In addition to these automatic safeguards and routine inspections, the facility performs regular groundwater monitoring to ensure that drinking water sources are not contaminated and annual testing is performed to confirm the mechanical integrity of the well and formation conditions.
Safe Design: A Well Within a Well
Protection of drinking water is the primary concern in the construction of a disposal well and is achieved by assuring permanent containment of the waste.
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Sources: Chemical Manufacturers Association, 2501 M Street, Washington, DC 20037
Petroleum Geology, Exploration, Drilling, and Production, 2nd Edition, by Norman J. Hyne, Ph.D., PennWell Corporation, Tulsa, OK, 2001
Geophysical tool: “Cement Bond” logs (sonic log) after installation of surface casing (2) and injection tubing (5) established for quality control to ensure proper seal integrity from top to bottom.
On-site Monitoring
Injection well and ground water monitoring
- Mid-Way Environmental ground water monitoring program monitors ground water monthly to ensure that any adverse impact to groundwater is quickly identified and reported to the Oklahoma department of environmental quality (ODEQ). Reports are published on a quarterly basis originating from (5) 120’ deep wells on-site. In addition, The 260’ deep monitoring well is monitored on a monthly basis.
- The Groundwater sampling and analysis plan (gsap) includes a statistical analysis plan for the facility.
- Injection well is monitored during well operations for injection fluid quality, injection pressure, injection temperature, annulus pressure and flow rate. Mechanical integrity testing is performed every year and reported to ODEQ.
- Deep well monitoring well for the lowermost Underground source of drinking water aquifer (260’).
- Deep monitoring well for the uppermost groundwater aquifer (120’).
Seismicity
Not all injection wells are of the same design and purpose.
- Seismic activity reporting required within a 10 mile radius of the injection well
- Historical data reveals no seismic activity or active fault lines in the immediate area of Mid-Way Environmental’s Class 1 well in the Davenport, OK, area.
- The MES class I injection well injects at no more than 1200 psi max and 170 bbl. per minute, normal injection pressure will average between 350 and 570psi. Surface pressure depending on the density of the water which is a much lower PSI and GPM than other injection wells for oil well fracking at 3500 surface PSI and 1600 to 2700 bbl. per minute or 40,000 to 65,000 bbl. per day.
- Bottom hole pressure is roughly 3x surface pressure equaling approx. 1500 psi for the mes class I well as opposed to 11,000 psi for the typical oil company fracking well.
Class II Injection Well
Purpose: Regulate and manage safe injection (1) of fluid brought to the surface in connection with oil and gas production and some natural gas storage operations, (2) for enhanced recovery of oil or natural gas, or (3) for hydrocarbon storage operations. Prohibit movement of fluids into USDWs.
Examples of Fluids:
Produced high salinity brine
Crude oil (for storage)
Polymers and vicosifiers for enhanced recovery wells
Drilling fluids and muds
Protective Requirements:
Construction and siting
Cased and cemented to prevent movement of fluids into USDWs
Construction and design of well (casing, tubing and packer) varies
Monitoring and Reporting
Plan for safe plugging and abandoning of wells, including demonstration of financial responsibility
Regulatory Citations:
40 CFR 144 Subparts A – E
40 CFR 146 Subparts A and C
Source: EPA Protecting Drinking Water Through Underground Injection Control: UIC Pocket Guide
