Marcellus Shale Deposit Frac Water Make-up
From 1 to 10 million gallons of fracture, “frac”, water, mixed with various additives, is required to completion fracture each horizontal deep well. Once used, this now contaminated water must be removed from the well, generally 10 to 40% is recovered, and is commonly referred to as “flowback” water. Typically, flowback water contains high dissolved solids with varying levels of various other constituents such as barium and strontium.
Metals and acid-producing minerals
Marcellus shales are known, in some regions, to contain acid-producing minerals such as pyrite and sulfides.
The Pennsylvania Department of Conservation and Natural Resources publishes a map that indicates which formations are likely to contain acid-forming minerals. The lower part of the Marcellus formation is on the map.
Conditions
Due to the high dissolved solids content and presence of various other constituents,
disposal of flowback water is becoming very difficult and costly.
Obtaining the needed water to makeup frac water, with subsequent disposal of the flow-
back water, presents a significant problem for gas production firms. In many areas, the
amount of suitable water needed for formulation of frac water is just not available.
The best solution to this combined wastewater disposal and water supply problem is to
simply treat and recycle the flowback water, over and over again, as frac water.
In many areas of the state where the Marcellus shale is present, the same conditions of
acid mine drainage exist from past coal mining activities and the same metals are pre-
sent in large amounts and is a major water quality problem.
FRAC FLOWBACK WATER TREATMENT
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