The Growth of CBM/CSG and the History of Water Management

Unconventional natural gas production from underground coal seams, such as Coal Bed Methane, is now considered to be one of the greatest untapped energy resources developing around the world. Untapped reserves are estimated in the trillions of cubic feet of available gas, and large energy companies are buying or leasing millions of acres of property around the world that hold gas rich coal seams for development.

For most Coal Seam Gas wells and some Shale Gas Wells, enormous quantities of water must be pumped from these wells in order for the Natural Gas to be released from these coal seams. A Gas Production Company may have to pump as much as one hundred thousand barrels of water per day from a small field of one hundred wells in order to have regular and consistent gas production. Over the last fifteen years there has been an incredible transition in the disposal of CBM produced water. Most of this transition has been led by environmental concerns about the quantity of water that is being drained from our large underground aquifers and the potential environmental impact of this surface discharged water.

The removal and disposal of “water” from CBM wells is one of the biggest costs, delays and environmental concerns for Gas Production companies. Traditional methods of water mitigation involving surface discharge have become un-economical or legally unviable in many regions of the world. Environmental experts estimate, and many are demanding, that any method of surface discharge is subject to severe world-wide limitations.

CBM Operators and Environmentalists are asking the same questions:

What is the most cost effective and environmentally friendly method for managing the water that is currently being pumped from thousands of Coal Seam Gas wells all over the world?

What improvements can CSG/CBM Operators make to better handle the water that must be pumped from thousands of new wells that will soon be coming online around the world in order to obtain this abundant energy resource?

The End of Surface Discharge

When Coal Seam Gas production was first developed, limited environmental and regulatory oversight existed. Initially, Gas Production Companies discharged the CBM produced water to the nearest drainage and into a local waterway. Unfortunately this type of surface discharge is not a desirable and in most places becoming an unacceptable solution.

In many areas, permits for this type of discharge are no longer allowed and existing permits are not being renewed. Further seasonal restrictions of surface discharge to waterways limits the amount of water that can be discharged, often causing gas wells to be shut in, stopping gas production. While unmitigated surface discharge was inexpensive, it was not effective at saving usable water for the landowner, and in some cases, there was negative environmental impact on the soil and waterways.

As environmental concerns increased, impoundment ponds became the next step in produced water management. Production costs rose as these structures required long timelines for planning, eighteen month permitting cycles, large reclamation bonds, and large upfront cash outlays for development.

Landowners had to endure extensive surface disturbances as large quantities of produced water was pumped into numerous containment ponds on their property or to large centralized ponds at other locations. Production Companies were spending millions to build water impoundment structures that would eventually have to be removed at great additional cost to the operator when the gas wells were depleted. In winter months ice flows and limited evaporation reduced capacity for water disposal, again causing wells to be shut in, also shutting down gas production.

With continued regulatory oversight, multi-million dollar treatment facilities were erected to improve the quality of surface discharged water, but the cost per barrel of treated water has become un-economical, and further surface discharge of the water after treatment is either limited or unviable. Trends indicate that most CBM Production Companies are now closing their treatment facilities, as the ongoing costs of “treating” such enormous quantities of water is not economical and the ability to surface discharge is disappearing.

There have been limited attempts to curtail surface discharge by drilling very deep high pressure “disposal” wells, to dispose of water that is piped from multiple production wells to one disposal well. This process injects the produced water under very high pressure to unrecoverable depths. This water is forever lost for future use by the local landowners. These types of wells are very expensive to develop and operate and have a higher risk of failure. Further, if the injection well breaks down for any reason the entire field is impaired, along with all the gas production adding further cost and revenue loss to this type of water disposal.

The Trend Toward Aquifer Recharge Systems

The only economical, environmental, and landowner friendly solution requires that CBM produced water is NEVER brought to the surface. Since 2007, there has been increased development and successful large scale implementations of a new type of Aquifer Recharge Technology. Aquifer Recharge Injection Systems for CBM wells have proven to handle large quantities of water at very low costs. This introduction began in the Powder River Basin of Wyoming, but is spreading across the US and to various countries that need to manage CSG produced water. With this type of Aquifer Recharge Injection System the produced water is NEVER removed from the production gas well. This has eliminated an array of costs and issues, while proving to be the most cost and time saving method for managing produced water while maintaining consistent gas production.

For CBM Operators, these Aquifer Recharge Systems dramatically reduce de-watering costs. While many companies were spending in $0.15 to $0.40 per barrel for ongoing water disposal, these Aquifer Recharge Systems have much lower up-front costs and reduce ongoing costs to as low as $0.02 per barrel for high volume water production.

This type of Aquifer Recharge System keeps all the produced water subsurface and within the production wellbore, eliminating water piping, outfalls, impoundments, and treatment, while allowing the released gas to rise to the surface for normal collection. In this Aquifer Recharge system, the water is re-injected immediately in the same well bore as soon as it is pumped from the coal seam. This type of Aquifer Recharge System is known as ARID.

ARID Aquifer Recharge Systems are Different

With ARID, water is pumped out of the coal seam and into an available aquifer with like water quality in the same well bore. As part of the Solution, qualifying receiving zones are identified for each well and tested to insure optimal long term environmental safety and viability. A major advantage of ARID is that each production well operates independently as its own injection well; therefore if one injection well goes down there is no impact on any other wells.

ARID Systems work under relatively low pressure, eliminating surface pressure concerns, avoiding costs and risks of high pressure injection, and enhancing the long term potential of the receiving zone. With low pressure re-injection, receiving zones will consistently accept large quantities of water over many years. Many zones will handle water recharge rates in excess of 75 gpm.

ARID Systems are the most environmentally and landowner friendly method for retaining usable groundwater, and therefore the permitting process is much less time consuming and less expensive in comparison to surface discharge or deep injection water management methods. ARID is usually permitted in weeks rather than the many months currently required for permitting surface discharge, if surface discharge permits are available at all.

In addition to all the benefits for CBM Operators, this Aquifer Recharge System is very attractive for landowners. ARID will “recharge” shallow aquifers at a significant benefit to the current or future landowners. Consequently, landowner negotiations are often expedited due to the potential improvement of an easily accessible water supply. Landowners are often able to obtain beneficial “water rights” on the water that is re-injected, enhancing the property value. All concerned parties favor the low cost and environmental benefits offered by the ARID System.