Subterranean Operation-Hydraulic Fracking
Subterranean operation refers to an activity happening underground, one of such activities include hydraulic fracking. The literal meaning of the term “hydraulic fracking” is to facilitate fracturing of anything by virtue of a fluid. However, majorly, the term is quite famous for one of the subterranean operations, that enables extraction of oil and gas from the ground. Other similar terms to the hydraulic fracking are “hydraulic fracturing”, “fracking”, “hydrofracking”, “hydrofracturing”. First hydraulic fracking was conducted on March 17, 1949, which was pioneered by Halliburton. The company performed hydraulic fracking in Stephens County, Oklahoma, and Archer County, Texas to extract oil and gases from a pre-drilled wellbore.
Hydraulic fracking is now widely practiced across the globe to facilitate obtainment of oil and gases from underground. Before conducting hydraulic fracking, a process called well bore simulation is performed. A well bore of several meters, for example, 2500m – 3000m is drilled deep down through a layer of sediments by way of a drilling tool. The drilling tool after drilling the well bore up to its kick-off point, turns almost 90 degrees to carry out further drilling in the hydro-carbon bearing rocks, called shale rock formations. The drilling tool can drill up to 2 miles after the kick-off point. After creating a well bore, a well casing is deployed that surrounds around the periphery of the well bore. Sometimes a layer of cement is deposited outside the casing, which acts as a barrier to the well bore from the surrounding environment, for example, fresh ground water and aquifers. A perforating gun is inserted within the bore casing to create a series of small holes in shale rock formations, such that, upon firing the perforating gun, the holes get burst through the well casing and extend up to the shale rock formation. This completes the well simulation process for hydraulic fracking.
The fracking can be realized in two stages that are a pad stage and a slurry stage. The pad stage can be executed by injecting fracturing fluids within the well bore, which creates cracks or fractures in shale rocks in the well bore. Pad stage is called so, because, the fracturing fluids, upon injection into the well bore, are capable of producing pads (cracks) within the well bore. Subsequent to the pad stage, the fracturing fluid is blend with slurry or acid to form a proppant. Proppant may be a blend of fine mesh sand, ceramic, or the like material. During slurry stage, the proppant so formed in injected at high pressure such that the proppant gets positioned/disposed on the pads created during pad stage. As the name suggests, the proppant, upon injection into the wellbore, props the fractures created during the pad stage, therefore: the slurry stage is also known as prop stage. Proppant stage allows to keep open the fractures for a longer period of times, which facilitates the oil and gases to leak out from their rocks. The oil and gases, so leaked are directed towards the well casing, from where, they are raised up to the ground level. This fluid containing hydrocarbon is now treated to separate the hydrocarbon from the remaining fluid.
Coming to set-up requirements for realizing hydraulic fracking, a group of fleets are deployed on the ground to carry out the fracking. The fleets are capable of simulating the wells for hydraulic fracking and pumping the fracturing fluids and slurry within the well bore to instigate necessary fractures within the rock formations.
Depending on the quantity of the hydrocarbon that are present at a particular underground site, there are various procedure to carry out hydraulic fracking, for example, one of the procedures being multistage hydraulic fracking. Multistage hydraulic fracking requires intermittent deployment of plugs within the well casing. A plug within the well casing facilitates ejection of oil and gases from a particular span of well casing. Therefore, multiple plugs, when deployed intermittently within the well casing facilitates ejection of oil and gases from the number of spans of the well casing and hence enabling ejection in various stages.
There are various disadvantages associated with the hydraulic fracking, for example, deployment of a number of fleets consumes good amount of energy. Further, while digging deep inside the earth, there remains a possibility of bursting out of the well casing near the ground water, from which emanates the hazardous effects to the ground water. The damage is not restricted to underground, rather the execution of hydraulic fracking causes leakage of methane gas to the environment.
The adverse aspect of the hydraulic fracking necessitates us to rely on renewable energy resources, for example, solar energy. Going forward, the researches are innovating around harnessing of solar energy that eradicates the large set up that is required to extract hydrocarbons from underground.