Hydraulic Fracturing (fracking) and Its Impact: What it is & How it Works

Posted on Jan 30, 2024 at 10:01 PM

We note that hydraulic fracturing technology is a widely spread modern technology, and it is commonly used in complex exploration and extraction cases in the oil and gas industry.

In today's article, we will provide general information about hydraulic fracturing, how it works, and its effects and implications. 

What is Hydraulic Fracturing?

Hydraulic fracturing is just one small method of the broader unconventional oil and natural gas development process. Fracking is a proven drilling technology that extracts oil, natural gas, or water from deep underground.

Simply put, fracking is a technique or method that relies on injecting fluids and materials at very high pressures into the layers of rock formations that store hydrocarbon resources such as oil or gas. It aims to create cracks, fissures, or fractures in these layers to increase the flow of these resources and stimulate production from the well. Or to improve safety when extracting after the completion of drilling operations and removing both the crane and the rig from the site.

The hydraulic fracturing process can take between one to 10 days to complete. Hydraulic fracturing can occur during three stages of the petroleum development cycle – exploration, evaluation, and production. Generally, the process is undertaken only once for the life of a well.

During exploration, hydraulic fracturing can be used in a vertical well to test different rock formations. During evaluation, multiple vertical and horizontal wells may be drilled and fractured to determine the physical extent of a newly discovered gas field. Vertical or horizontal wells are drilled during production and can undergo hydraulic fracturing to enhance commercial flows of hydrocarbons.

Hydraulic fracturing was first used in Kansas, USA, in 1947 to extract natural gas from a Limestone formation in the Hugoton gas field. Since then, petroleum engineers have regularly used hydraulic fracturing to increase sound production.

More than 1.7 million U.S. wells have been completed using fracking, producing more than 7 billion barrels of oil and 600 trillion cubic feet of natural gas.

How does Hydraulic Fracturing work?

In preparation for hydraulic fracturing, the steel casing lining the well is perforated at specific depths to create a series of holes and channels in the rock layers. This happens by lowering a tool called a perforating gun, which, once placed, creates small holes a few inches long in the surface casing. These holes increase the contact surface between high-pressure fluids and rock formation. Thus, a network of small cracks in the rocks is created when pressure occurs.

Then, the fracturing fluids are pumped, usually 90% water and 9.5% proppant (usually sand). The proppants suspended in the fluid remain in the fractures and hold them open after the pumping has stopped. The remaining 0.5% are chemicals added to the mixture.

As a result of the high pressure when pumping the liquid, the liquid comes out of the perforated holes. The high pressure of the fluid provides enough pressure to open cracks in the rock so that various fossil fuels, gas or oil, begin to flow through the surface casing tube into the wellhead. That is, it became possible to start the extraction process.

These fracture pathways are typically 3 to 6 millimetres wide but can extend 400 metres horizontally and up to 100 metres vertically within the gas-bearing rock formation.

Each well to be hydraulically fractured is carefully designed based on scientific models of the rock’s properties, and the process is closely monitored in real-time because of the high pressures involved (690 bar)

Production can last 20-40 years, depending on the size of the reserves. Wells are filled, and pipes are sealed below ground once production is no longer economical. Companies should remove all surface equipment and return the land to its previous state.  

Usually, Up to 80 per cent of the fluid used during a hydraulic fracture stimulation can be recovered. If not reused in another well, the fluid can be stored safely, and the water evaporates naturally, leaving a slight residue. This residue is tested, removed safely, and disposed of if required at a licensed waste facility. The water used in a fracturing fluid may be fresh, saline, bore, or recycled.

The chemical additives in the fluid serve the following purposes:

• To make the fluid thicker and suspend the sand in the fluid;

• To allow the liquid to flow more easily into the fractures;

• To prevent corrosion damage to the well;

• To stop bacteria build-up and

• To leave the sand proppant in the newly-created fractures.

Depending on the task, various compounds and chemicals are also used in fracturing. Includes:

• Hydrochloric acid: Dissolves minerals and initiates cracks in rocks 

• Methanol: Reduce rust on steel tubes, casings, tanks, etc. — only when fracturing fluids contain acid 

• Petroleum distillates such as benzene Reduce friction during high-pressure pumping  
  
  

Hydraulic Fracturing and Environmental Impact:

Fracking is an inexpensive way to extract oil or natural gas from impermeable rock that conventional drilling cannot reach. However, It is controversial because of the adverse effects it can cause. 

Beginning with the large quantities of water used in injections, each well consumes a median of 1.5 million gallons. Not only does this reduce the amount of water available for drinking and irrigation, but it also threatens to pollute local sources with contaminated wastewater.

 The same applies to air, similar to the danger of gas flaring. Fracking produces large amounts of carbon and methane, the leading greenhouse gases that cause global warming, and other air pollutants (such as nitrogen oxides and hydrogen sulfide). These air pollutants can cause health problems and climate change.

In addition to air and water pollution, fracking can have long-term effects on the soil and surrounding vegetation. Wastewater spills' high salinity can reduce the soil's ability to support plant life.

Fracking has also been blamed for seismic activity. Following the hydraulic fracturing boom, tremors have risen dramatically, especially in areas with frequent drilling. At the same time, some research and other studies show that fracturing has nothing to do with earthquakes.

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