Final answer:
Directional and horizontal drilling in shale extraction have environmental advantages such as minimal surface impact and reduced water usage, but they also have disadvantages like potential groundwater contamination and increased seismic activity.
Step-by-step explanation:
Environmental advantages of directional and horizontal drilling in the process of oil extraction from shale, compared to oil sands:
Reduced surface impact: Directional and horizontal drilling techniques require fewer well sites, resulting in less disturbance to the surface environment compared to strip mining in oil sands extraction.
Decreased water usage: Although hydraulic fracturing (fracking) is used in both shale and oil sands extraction, the process typically requires less water for shale drilling as it involves creating fractures within the rock rather than excavating and processing oil sands.
Environmental disadvantages of directional and horizontal drilling in the process of oil extraction from shale, compared to oil sands:
Potential groundwater contamination: Fracking operations for shale drilling can lead to the contamination of groundwater sources if proper measures are not taken to ensure the integrity of well casings and prevent the migration of fluids and gases.
Increase in seismic activity: Hydraulic fracturing has been linked to induced seismicity, or human-induced earthquakes, in some regions where shale drilling occurs. The injection of fluid into the rock formations can increase pore pressure and cause the underlying faults to slip, resulting in earthquakes.