HOW IS NATURAL GAS EXTRACTED
Natural Gas is extracted either onshore or offshore by drilling. The process involved is nevertheless not as easy as just drilling and completing a well there is the underground environment to consider where any of such factors can heavily impede the free flow of products in the well. Advanced technology has enabled more successful drilling to a production of about 60% of the available resources from a formation.
Methods of Drilling
A drilling strategy is formed on the basis of the characteristics of the site. Once a site is identified and deemed worthy, roads are constructed to the pad site and proper grading of the area is done where the rig and other equipment will be placed.
a) Hydraulic Fracturing
Water, sand and the chemicals injected into the sub-surface increases permeability. The chemical used perform the role of increasing friction and protecting the well from rust and bacteria. When these chemicals are mixed with water, they form the fracturing fluid which has sand as the channel. The well gets to be lined with concrete and steel to prevent seepage into ground water.
Hydraulic wells can be drilled either vertically or horizontally with the vertical being cheaper but more dangerous to the environment and the horizontal being more costly but with higher extraction rates from single wells.
Horizontal drilling is safer to the environment as several laterals can be drilled from only one surface drilling pad hence easing the impact on the surface environment.
b) Percussion Drilling
This method is used for shallow wells where a heavy metal bit is heaved directly above the location of a well and dropped until it strikes the oil. Percussion drilling poses the challenge of mud accumulation at the bottom since this mud has to be clear from time to time.
This method laid the foundation for more advanced drilling like the rotary drilling. With such an improvement it is expected that technology will continue to be developed to improve safe and economic extraction techniques.
c) Rotary Drilling
This method allows exploration of oil deposits that are wider than deep. The deposits must be tapped by pipelines which can move horizontally as far as one mile. The pipelines can be aimed with directional drilling towards the most concentrated parts of the deposits.
d) Rigs and Platforms
Rigs and platforms are necessary to provide a solid surface above a body of water from which to rill in offshore drilling.
Shallow water drilling solutions include barges and jack-up rigs and the submersible rigs
Deep water solutions include platforms attached to the sea floor thus forming fixed rigs. These are costly and depend on the recovery of large amounts of natural gas
When all the natural gas that can be economically extracted from a site has been produced, the land has to be returned to the way it was before the drilling.
The wells can be filled with cement, all surface equipments removed and all pads filled in with earth or replanted. This ensures that the land can be used again in other activities.