After a little hiatus, we are back with part two of our series on flowback water treatment issues and technology. After water, sand and dissolved solids the next are of interest to all are the free and dissolved hydrocarbons present in the flowback and producted water.
The driller actually adds very little of these compounds into the frac liquids going down the well. While no recipe is the same, the only real hydrocarbons used today tend to be the glycols used in descaling and some light petroleum distillates for viscosity enhancement. Together these would represent less than 0.1% of the frac liquid volume.
The flowback on the other hand has been known to contain "some" free and dissolved hydrocarbons, that come from the formation itself. Rationally, this makes sense as the frac fluids are held under very high pressure for long periods of time to fracture the well prior to flowback. This would give the compound present in the formation both time and energy to dissolve into the flowback water. Many of these are lighter than water therefore they rise up with flowback. There concentrations are very low in the flowback (normally), typically below 100 parts per million.
The good news is that regardless of concentration, these compounds can and are removed easily with a range of filtration and adsorption equipment readily available to any operator. Technologies such as oil absorbents and physical adsorbent media like activated carbon are inexpensive and provide for easy removal efficiency. These companies are already present in the shale and have off of the shelf technology that can be mobilized to a site in hours, not days or weeks. These technologies have been serving the chemical, manufacturing and related industries for years in this region and the infrastructure is already present to take advantage of these new markets.
This is a positive on two fronts. First, if the water is to be recycled in the fracking operation the removal of these compounds is important to ensure the highest water quality available for the next hydraulic fracture. In the event the this water is to be send off for disposal, the removal of all of the dissolved and free organics is particularly important as the water will be discharged eventually under very strict EPA regulations already in existence. (The National Pollution Discharge Elimination System - NPDES). Every state runs their own NPDES permitting system and any facility with a discharge permit must meet strict discharge guidelines.
As I mentioned in an earlier piece, none of the contaminants found in the flowback water are ones that the water treatment industry has never dealt with or managed. As the drilling continues, so will the continued growth of service firms to assist the drillers with their water management.
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