--> Abstract: Economic Production of Sandbed Methane from Ground Water; #90063 (2007)

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Economic Production of Sandbed Methane from Ground Water

 

Player, Gary Farnsworth1 (1) Gary Player Ventures, Cedar City, UT

 

Methane can occur as a solute in ground water, or as undissolved “free” bubbles of gas. Sand Bed Methane is recoverable methane that occurs dissolved in ground water in permeable layers of sandstone and loose sands. Dissolved gas from aquifers with high enough gas water ratios (GWR) can be economically produced by pumping ground water to the surface, recovering the methane in separators, and returning the water to the same aquifer.

 

High pressures that exist at great depths provide relatively high methane solubility in ground water aquifers. Laboratory research data and production histories from Japanese Sand Bed Methane wells show that dissolved methane concentrations range from about 10 cubic feet of methane per 42 gallon barrel of water at 3,000 feet below ground, to about 30 cubic feet of methane per barrel of water at 10,000 feet below ground. Where reservoir rocks contain unrecovered free gas from a depleted gas field, along with dissolved gas, the GWR could be much higher. For example the GWR in water recovered from a "blown down" gas field could be more than 100 cubic feet per barrel.

 

California's Great Valley Sequence contains great volumes of thick permeable sandstones that contain more than 1,000 Trillion Cubic Feet of dissolved methane. Similar volumes of gas are present in deep aquifers in much of the United States. Markets are available and regulatory agencies are amenable to Sandbed Methane production.

 

AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California