What Does Hydraulic Fracturing Mean?
Hydraulic fracturing is a method used to extract oil and gas from shale rock. Rather than simply drilling, hydraulic fracturing also involves pumping fluid (a mixture of water, sand, and a chemical propellant) into the well to fracture the shale, releasing oil and gas.
This method can also be used in other low-permeability rocks, such as tight sandstone and coal beds. It also has other applications, such as determining the in-situ stress of rocks, tunneling, groundwater remediation, and water well development.
Hydraulic fracturing is commonly known as fracking.
Safeopedia Explains Hydraulic Fracturing
Hydraulic fracturing involves the injection of high-pressure fracture fluid, which contains about 95% water, 0.5% additives, and 4.5% proppant (typically sand). This creates fractures in the rock that expand as the proppant fills them. Suspendable proppants such as sand or gritty material are used to keep the fractures open even after pumping has stopped.
The fractures formed by this process are typically only three to six millimeters wide but can extend up to 400 meters horizontally and 100 meters vertically.
Applications of Hydraulic Fracturing
Hydraulic fracturing is best for stimulating low-permeability rocks, as it offers high resistance to fluid flow. Some reservoirs are damaged during the drilling process, as drilling or completion fluids may leak into the reservoir, plugging the pores and pore throats. Hydraulic fracturing can be used as a solution to this problem.
Additional applications of hydraulic fracturing are:
- Connecting the wellbore to natural fractures or cleats in a formation
- Minimizing sand production by decreasing the pressure drop around the well
- Minimizing problems with asphaltene or paraffin deposition by decreasing the pressure drop around the well
- Enhancing gravel-packing sand placement
- Increasing the area of the formation in contact with the wellbore
Hazards at the Fracking Site
All employers are mandated by the Occupational Safety and Health Administration (OSHA) to provide their employees with the training and equipment for them to carry out their work safely. Some of the hazards faced by workers in the fracking industry include:
- Slips, trips, and falls - Falls can occur from rig sides, ladders, derricks, and truck beds. Workers can also trip over wires and hoses or slip on slick surfaces.
- Struck-by - Workers can be struck by falling trees, pipes, tongs, chains, high-pressure hoses, tools, cables, and falling objects.
- Caught-between - Workers can be crushed by or caught in rotating or unguarded machinery.
- Confined spaces, electrical power lines, trench collapse
- Chemical handling and exposure
- Exposure to silica
- Weather condition - Fracking sites are often located in remote locations where temperatures often reach extreme highs or lows.