Shale Gas Frac Waters – Treatment, Re-use and Disposal
Shale gas exploration & production is a topical subject not only in the oil & gas industry but to many of the public in general, not least because of the publicity surrounding fracking of new wells possibly causing earthquakes, contamination of potable water supplies, air pollution and contribution to climate change (but reduced or increased is arguable).
A boom in shale gas production in USA has had dramatic effects on creating many thousands of jobs, including apparently rejuvenating the petrochemicals industry due to availability of cheap feedstock natural gas.
Shale gas waste-water treatment requirements are somewhat different to those for normal oil & gas produced waters because of the high number of wells being drilled and fracked, and those give frequent , high volume spikes of flow-back frac fluids in a typically low flow-rate of condensed and/or formation waters. The flow-back fluids typically have quite high concentrations of polymers (drag-reducers in ‘slick’ water to reduce pressure drops, and viscosifiers to help carry sand proppant), plus corrosion, scale and bacteria inhibitors.
The tremendous increase in gas production in the USA has led to a 6-fold fall in gas prices, and that alone means that water treatment costs (both CAPEX and OPEX) have to be minimised, but without giving any risks to potable, shallow water aquifers – so water management practices must be of the highest standards possible.