What is a horizontal well
A horizontal well is an oil or gas well dug at an angle of at least eighty degrees from a vertical well bore. This technique has become more and more common and productive in recent years. The horizontal well is a type of directional drilling technique. Operators use it to recover oil and natural gas in situations where the shape of the tank is abnormal or difficult to access.
DISTRIBUTION of the horizontal well
Horizontal wells played a more important role in the extraction of fossil fuels in the 2020s. As technology developed, horizontal drilling reduced costs and improved the efficiency of oil extraction and natural gas, particularly in the United States.
The emergence of horizontal wells was facilitated by two components of the drilling rig.
- The mud motor is a pump mechanism that penetrates the earth, supplied by a supply of drilling fluid, known as mud. Adjustments to the mud motor configuration allow it to steer a bit in non-vertical directions.
- The measurement during drilling (MWD) device, which allows real-time analysis of underground conditions and provides a target for horizontal drilling.
Modern drilling techniques allow the use of drills that can bend. This folding, accomplished through the use of hydraulic jets, allows engineers to adjust the direction of drilling to some extent. It has become a more popular technique, as computer aided technology has become more common. The angle of the drill used can be adjusted by a computer using global positioning signals (GPS) to locate the location of the drill relative to the oil or gas field.
Improved underground access thanks to horizontal drilling
Horizontal drilling has become a valid technique in recent years due to certain advantages over traditional vertical drilling. It provides access to underground tanks which may not be directly accessible from above. It allows a drilling platform, or launch point, to explore a larger underground area.
Horizontal drilling can also be used to seal or relieve pressure on an out of control well by drilling an adjacent relief well. Finally, beyond the goal of oil extraction, horizontal drilling can be useful in the construction of underground pipelines or utility lines that must travel under a river or an existing building.
Horizontal drilling and hydraulic fracturing
Horizontal wells have been found to be particularly useful as a component of the hydraulic fracturing process. Fracturing is useful in extracting natural gas and petroleum from large shale reservoirs in the United States. These deposits tend to be inaccessible to traditional vertical drilling due to the impermeability of shale formations.
Instead, oil and gas companies drill horizontally in the shale and pump a compound of water, chemicals, and guar gum, also known as mud, into the shale. The force of these injections fractures the rock, creating openings through which the oil flows.
The main shale deposits in the United States include the Marcellus shale from the Appalachian Basin and the Barnett shale in Texas. Hydraulic fracturing was responsible for two-thirds of natural gas extraction in the United States in 2020. This technique has sparked controversy over fears that it may contaminate local groundwater sources and contribute to increased levels of seismic activity.