Hydraulic Fracturing

Richard (Rick) Mills
Ahead of the Herd

Page 1 of 3

As a general rule, the most successful man in life is the man who has the best information

 

Hydraulic fracturing, or fracking as it’s more commonly referred to, is used to stimulate the production of oil and gas from unconventional oil and gas deposits - shales, coalbeds, and tight sands. These types of deposits need to be stimulated because they have a lower permeability than conventional reservoirs and require the additional stimulation for production.

 

Hydraulic fracturing involves drilling a well then injecting it with a slurry of water, chemical additives and proppants. Wells are drilled and lined with a steel pipe that’s cemented into place. A perforating gun is used to shoot small holes through the steel and cement into the shale. The highly pressurized fluid and proppant mixture injected into the well escapes and create cracks and fractures in the surrounding shale layers and that stimulates the flow of natural gas or oil. The proppants (grains of sand, ceramic beads, or sintered bauxite) prevent the fractures from closing when the injection is stopped and the pressure of the fluid is removed.

 

Proponents of hydraulic fracturing argue that fracking:

  • Creates cheap domestic energy
  • Replaces dirty coal-fired power plants
  • Makes it easier to meet federal air and water quality standards
  • Reduces our dependence on foreign supplied oil

“Fracture stimulation is a safe and environmentally sound practice based on the industry’s decades-long track record, as well as the conclusions of government and industry studies and surveys.” Halliburton, a major corporate proponent of fracking

 

Opponents of hydraulic fracturing have some serious concerns regarding:

  • Contamination of the environment
  • Threats to human health
  • False promises of long-term economic benefits

Over the last several years there’s been a dramatic rise in the use of hydraulic fracturing. As use of this technology has increased worries are growing about fracking’s effect on our fresh water supply, it’s easy to see why:

  • Fracking just one well can use two to eight million gallons of water with the major components being water (90%), sand or proppants (8-9.5%), and chemicals (0.5-2%). One four million gallon fracturing operation would use from 80 to 330 tons of chemicals and each well will be fracked numerous times. Many of these chemicals have been linked to cancer, developmental defects, hormone disruption, and other conditions
  • Cracked wells and rock movement frequently leak fracking fluid and gases into nearby groundwater supplies. Fracturing fluid leakoff (loss of fracturing fluid from the fracture channel into the surrounding permeable rock) can exceed 70% of injected volume
  • Methane concentrations are 17x higher in drinking-water wells near fracturing sites than in normal wells. Hydraulic fracturing increases the permeability of shale beds, creating new flow paths and enhancing natural flow paths for gas leakage into aquifers

Here are a few excerpts from ‘Myths Versus Realities…Getting the facts about Fracking’ published by The Council of Canadians.

  1. Research by the U.S. Environmental Protection Agency and the U.S. Endocrine Disruption Exchange Inc. has demonstrated that fracking fluids contain toxic substances known to cause seri­ous health impacts such as cancer and organ damage, and can have negative impacts on neurological, reproductive and endocrine systems.
  2. A 2011 study by the U.S. Environmental Protection Agency confirmed the clear link between fracking and water contamination.
  3. Contamination of fracking fluids from one well to another – ‘fracturing communication incidents’ - has been documented in British Columbia. On May 20, 2010, the British Columbia Oil and Gas Commission (BC OGC) issued a safety ad­visory stating that they were aware of 18 fracturing communication incidents. The BC OGC’s advisory also confirmed that fracking fluids can return to the ground surface, which poses a significant threat to water sources as chemicals could leach into nearby watersheds.
  4. One study published in an academic journal by a professor at Cornell University suggests that fracked gas emissions may be worse than those associated with oil and coal.
  5. In a recent briefing titled Health Implica­tions of Fracking for Natural Gas in the Great Lakes-St. Lawrence River Basin, Dr. Theo Colborne noted that some workers were re­quired to sign contracts preventing them from ever revealing their hourly wage or health problems. They were not even allowed to call 911 in case of an accident or a spill. Workers who suffered from hypertension, fibromyalgia, chemical sensitivity, memory loss and depression could not get worker’s compensation because they could not prove their medical conditions were a result of chemical exposure.  

The fracturing fluids job is to create the fractures, hold them open, place the proppants, and then lose viscosity to flow back up the wellbore. It has to do all that without damaging the reservoir. Typical fluid types are:

  • Conventional linear gels. These gels are cellulose derivatives or guar (and its derivatives) based.
  • Borate-crosslinked fluids are guar-based fluids cross-linked with boron ions. These gels are used to carry proppants.
  • Organometallic-crosslinked fluids use zirconium, chromium, antimony, titanium salts to crosslink guar based gels. Gels are broken down with appropriate breakers.
  • Aluminium phosphate-ester oil gels. Aluminium phosphate and ester oils are slurried to form cross-linked gel.

Fracturing fluid additives include: proppants, acids, gelling agents to thicken the fracturing fluid, gel breakers which allow fracturing fluid and gas to flow easily back to surface, bactericides, biocides, clay stabilizers, corrosion inhibitors, crosslinkers which help maintain viscosity of fracturing fluid, friction reducers, iron controls, scale inhibitors, and surfactants. The fracturing fluid will vary in composition depending on the type of fracturing used, the conditions of the specific well being fractured, and the water characteristics.

 

A typical fracture treatment uses up to 12 additive chemicals to the fracturing fluid. The most often used chemical additives would include one or more of the following:

  • Hydrochloric acid helps dissolve minerals and initiate cracks in the rock and is the single largest liquid component used in a fracturing fluid aside from water.  
  • Acetic acid is used in the pre-fracturing stage for cleaning the perforations and initiating fissures in the near-wellbore rock.
  • Sodium chloride (salt) delays breakdown of the gel polymer chains.
  • Polyacrylamide and other friction reducers minimize the friction between fluid and pipe.
  • Ethylene glycol prevents formation of scale deposits in the pipe.
  • Borate salts are used for maintaining fluid viscosity.
  • Tetramethyl ammonium chloride prevents clays from swelling and shifting
  • Sodium and potassium carbonates are used for maintaining effectiveness of the crosslinkers.
  • Glutaraldehyde is used as a disinfectant of the water (bacteria elimination).
  • Guar gum and other water-soluble gelling agents increases the viscosity of the fracturing fluid to more efficiently deliver the proppant into the formation.
  • Formic acid and acetaldehyde are used for corrosion prevention.
  • Isopropanol increases the viscosity of the fracture fluid.
  • Methanol is a winterizing agent and product stabilizer

British Columbia’s Vancouver Sun newspaper reported a well in Peace River North, British Columbia, Canada used more than 30 ingredients. These ingredients included hydrochloric acid, xylene (a central nervous system depressant), naphtha, polyethylene glycol and kerosene.

 

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