Welcome to my primer on hydraulic fracing

How Hydraulic Fracking works:
As the well bore is being drilled, the bit grinds past layers in the formation.  Areas (zones) that produce gas are noted.  After the bore is in place, the gas producing zones are set with charges at points where the company wants to perforate or blow holes in the well casing – which will allow the gas in the gas producing zones to flow into the well bore.  The gas naturally wants to rise under great pressures which are exerted by the weight of the Earth, so will seek the easiest path out of its confinement.  Ideally, that means straight up the well bore as a produced product.

The charges are detonated, blowing apart the formation.  This causes additional faulting in the surrounding area – how much faulting is a matter of speculation and debate even among experts [additional info – see a scientific perspective of why fracing is flawed].  Hydraulic fluids are then forced into the new (and existing fractures) in order to prop them open.  The idea behind this is to extend the reach of the well bore into the formation (because it is not cost effective to drill every ten feet to try and tap into the pockets where they may lie underground).

Acid (usually hydrochloric – the strongest acid) treatments are also typically injected into the formation. the acid helps dissolve the fractures deeper into the formation further extending the reach of the well bore.   Diesel fuel and other products have been used as fracing fluids, and so has CO2 (carbon dioxide gas).  Other components of ‘frac’ fluids are benzene, toluene, surfactants (soaps), solvents, polymers (plastics), foaming agents, anti-scaling agents, corrosion inhibitors and environmentally toxic biocides, as well as patented synthetics – of which there are hundreds and none of which companies have to disclose under special exemptions.  Unfortunately, many of these fluids contain very toxic components, and in some cases, as with benzene, only small amounts can contaminate an entire aquifer.

Even if all the frac fluids are recovered (and about 40% of fluids are not recovered), the raw natural gas (primarily methane) that can communicate with water sources contains benzene, ethyl benzene, toluene, xylene and other constituents that are harmful to humans and wildlife.  And that is only what is known to be in raw natural gas.  The fact is, there has never been a commercial motive to analyze everything in natural gas – so a lot of what can migrate into aquifers remains unknown.  Now consider that of the known and unknown constituents, each can combine with other constituents and create chemical reactions – leading to all new compounds or physical changes underground – such as mobilizing harmful chemicals that otherwise would have remained locked in the formation. The potential for contamination is astronomical – and worst of all, largely unknown.

So, to get back to all the fluid/sand injection activity…. by fracturing the formation and forcing fluids and sand into the cracks at less of a density than the surrounding formation, the gas will migrate through these fissures and eventually end up in the well bore.  Natural earth pressures will push the gas up to the surface where it will be processed and collected into a pipeline.

In short, then, fracing is simply a process tacked onto the end of conventional drilling where producing zones are identified, and the casing is perforated with explosives to fracture the surrounding formation and prop open the fractures with fluids and sand in order to stimulate gas to flow into the bore hole.  This method is the method of choice in tight sands formations, or anywhere gas exists in small dispersed pockets underground.

Reprobate may choose to frac this well more than once.  If production slows down, in say a couple of years, more charges can be set, and the company will blow the hell out of the geology again. And again. And again.

You might ask, “What’s the big deal if the geology gets messed up way underground?” Well, the problem is that these explosions cause seismic pulses to travel primarily along existing fault paths, extending the energy from that pulse into the formation in the way of new faults – small or otherwise. It also creates some new pathways. This seismic activity causes the underlying rock layers to slip and shift creating more faults – and possibly sealing others in a process that is often grossly underestimated. Introducing extreme hydraulic frac pressure (enough to counter the weight of the compressed rock formation and existing pressures from gas and water) only intensifies this effect. These activities combined with the interception of pressurized gas pockets creates even more disturbance – much of which is unpredictable due to the irregularities and fluidity of tight sand formations as well as the inability to predict pressure. Now, couple all of this with depressurization that occurs as gas (and water by as much as 1-5 million gallons) is tapped off the formation and collected up the well bore. Much greater shifts and instability arise, compounded by subsequent frac jobs that can lead to greater formation failure. Big time pressure encounters (gas kicks and over pressurized water as they exit the wellbore) can really put the whammy on the formation. To summarize: Both instant and continued degradation of the formation occurs over time affected by numerous primary factors: 1) the nature of the rock (faults, fissures, caverns, slip zones and other instability) 2) initial artificial seismic and hydraulic stimulation of the rock (fracing) 3) frac disruptions causing the formation to respond with its own seismic reactions leading to even more highly unpredictable instability in a round-robin cascade effect  4) encounters of pressurized and over-pressurized gas and/or water (gas kicks, light or heavy) 5) depressurization of the formation as gas and water are produced and, 6) artificial re-stimulation of the formation through repeated seismic and hydraulic stimulation of the rock (for each stimulation, factors 1, 3, 4 and 5 are compounded).

Now, introduce fresh water aquifers and underground springs into the equation and you have a recipe for environmental disaster.

To make things even worse, let’s toss extreme down-hole density into the mix – and now you have this level of geologic degradation going on every ten acres underground.

Unfortunately, all of this underground interplay makes predictability a pipe dream and can produce effects that are made worse over time. Some adverse effects may show up relatively immediately, but some may not manifest until the well is long into its lifespan or perhaps after.



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