One of the recent developments in industry, shale production and distribution created the reliable assumptions of a revolution today. Shale revolution, as it’s commonly named, was positively influenced by the combined effects of horizontal drilling, as well as hydraulic fracturing. Generally, the hydraulic fracturing is the image mentioned by people interested in shale production, being improperly associated with the entire mechanism. In fact, hydraulic fracturing is supported and completed by the additional phase, horizontal drilling, assuring improved rates of exploitation.
Concretely, the constant improvement of horizontal drilling emerging in 1990, mostly in oil exploration area, perfection Mastery of horizontal drilling around 1990, originally for oil rather than gas exploration, was the essential change that radically transforms the shale exploration during the next 15 years.
According to David Blackmon, writing for Forbes in 2013, horizontal drilling is one of the most efficient innovations in both science and engineering, creating the opportunities of an improved production. Associated with hydraulic fracturing, horizontal drilling is able to offer an unmatched performance, accelerating the speed of the horsepower mostly in horizontal wells. In addition to the impressive speed, the fluids necessary for the preservation of water are refined, in this way the procedure is better targeted and creates improved results for long periods of time.
Fracturing exclusively has stirred the interest of companies involved in gas and oil production, due to its controversial and uncommon procedure, as well to its advanced results. David Blackmon suggests that despite increasing media presence, fracturing is a reliable procedure to create maximal profit.
Fracturing hydraulic managed to surpass in terms of popularity the implementation of horizontal drill implied in oil and gas production. Concisely, by using fracturing hydraulic companies are able to extract what they need from rock formations, previously untouchable due to their rigid shape, in this way the exploitation has been essentially revolutionized.
First experiments related to fracturing procedures date in the 1940s, the new technique being used to extract coal strata from gas seams. Due to its efficiency, USA companies constantly implemented during the last 50 years in gas, oil or coal exploitation.
According to a New York Times journalists writing in 1954 about the new procedure, fracturing was a reliable solution in terms of costs and results in the case of mixed coal and gas seams, mostly igniting the coal strata impossible to be properly exploited. Burning wasn’t a hazardous measure, it fact it generated an additional resource to be used by companies, the residual gas obtained from the ignition was transformed into fuel to supply the existing power system.
Fracturing was constantly improved, so that it creates a faster ignition, able to create a higher level of gas release. Inside an exploitation well, fracturing forces petroleum and oil strata reinforced with napalm to emerge, being captured and directed with the help of fast and large pumps. In several cases, the oil resulted in combined with sand, to be easier for later distribution and production. Fracturing procedure creates an incredible pressure, estimated at 12,000 pounds per inch, able to effectively crack the most rigid formations, allowing oil to drain into the already created channels. In the order to facilitate the drainage of the liquid implied for fracturing, Kerosene can be added. If there is any sand remaining after the introduction of all liquids, it will increase the force of the fracturing.
The episode mentioned in New York Times is only an example of the interest developed by companies and people in the implementation of fracturing hydraulic. During the next decades, the procedure, as well as the additional mechanism of exploitation such as the use of acids to crack formations of carbonate, captured the attention of American and worldwide companies interested in the exploitation of gas and oil. Initially, the required experiments were implemented by the U.S. Bureau of Mines, having teamed with companies such as Halliburton and other companies involved in oil exploitation, indicated the essential role played by the federal government and private companies in emerging energy revolution.
Paradoxically, horizontal drilling is as well new, yet old such as fracturing. Starting with Antiquity, mostly in Egyptian deserts or Iranian deserts, people were eager to use horizontal wells to drill for oil, necessary to support local economies.
In Europe, the ancient Greek historian Polybius is the first one to describe the increased performance of horizontal wells in the case of water production. In contemporary context, horizontal wells and their particular drilling is mentioned in January 1996 in the special edition of Schlumberger’s “Middle East Well Evaluation Review: Horizontal Highlights”.
As a matter of fact, horizontal drilling was widely implied during the last century in multiple exploitation areas. In 1891, the first patent for a specific horizontal drilling method is obtained.
Horizontal drilling was mostly implied in the case of dental projects, but the person applying for its patents, mentioned that a similar technique could be implemented in the case of various engineering.
In USA, the first reliable horizontal well dedicated to oil exploitation was mentioned in 1929, in Texas. Few decades later, in 1944, an additional drilling well was noted to be active in Pennsylvania.
Similarly to USA, China attempted to implement the technique of horizontal drilling in 1957, followed few years later by the Soviet Union, according to the U.S. Energy Information Administration (EIA). In the case of these countries, the revolutionary method was synonym with an expensive procedure, generated double or even triple costs, comparing with the performance of common vertical wells, as consequence it didn`t stir the interest of many companies, preferring the old method of drilling.
Despite the global reluctance, horizontal drilling became popular after 1989. According to Schlumberger, before this moment, most companies in oil industry were focusing on the old method of exploitation, horizontal drilling the last solution to be implied. Statistically, in 1989 only 200 horizontal wells were used worldwide. One year later, their number reached the level of 1,200 wells, the biggest increase being registered in USA, where nearly 1,000 horizontal wells were created.
In terms of costs, according to the EIA, global costs related to the implementation and functioning of horizontal wells decreased with 17%, since a large number of companies became interested in using the revolutionary technique, creating opportunity on the long-term for other companies willing to implement it.
The challenge of creating horizontal wells was associated with additional provocations. In order to increase the speed and quantity of material obtained through horizontal wells, companies had to also implement flexible drill pipes, as well as a particular type of motors based on an orientation-selective pattern. In addition, drillers are constantly monitored in real time as they crack the rocks, so that any potential inconvenient related to the dimension and depth of the well to be reduced.
Generally, oil and gas strata are retrieved in basins of sediments, concretely displayed as a group of pancakes on the same plate, which is rock formation. Exploitation can be different from a project to another, but in most of the cases the valuable strata are very close to the surface, being large enough, covering hundreds of square miles.
Due to this common distribution, vertical wells couldn`t properly reach the gas and oil strata aimed by the companies. On the other hand, a horizontal well can effectively target the required strata, either they are located at few meters or by contrary few kilometers depth.
Initially, horizontal wells were avoided by companies, willing to exploit harsh formations such as shale or chalk, since they generate low permeability. Another reason why they were considered as reliable second solution is the level of exhaustion they create, producing more water than oil or gas itself.
Elf Aquitaine, a French oil company would change this perspective. The company created in 1980s horizontal wells in southwest France and in the Mediterranean. Similarly to the French company, BP implemented horizontal wells in Alaska, obtaining the reduction of water and gas into the oil strata meant to be exploited.
Since 1990, horizontal drilling started to be implemented worldwide. According to the EIA, Texas was the world`s leading area, with 850 horizontal wells in the Austin Chalk, followed by North Dakota.
Impressively, in August 1990, 70,000 oil barrels per day were produced by Texas` horizontal wells.
Oman is another area where horizontal drilling dramatically changed the production. If in 1986, Oman’s national oil company was able to drill its reservoirs with the help of only three horizontal wells, four years later, the country managed to obtain better results. In 1994, Petroleum Development Oman reported that the country sustained its massive oil production through the agency of 200 horizontal wells.
Similarly, in Abu Dhabi or Saudi Arabia, at the beginning of 1990s, there were only 50 horizontal wells drilling for oil. According to Schlumberger, the Arabian countries adopted the new strategy for better results in the case of the exploitation located in the so-called Neutral Zone, an area shared with Kuwait.
Schlumberger noted in 1996, that horizontal drilling faced an unmatched evolution. The author argued that by the end of century, almost 50% of the wells drilling in USA will be mostly horizontal, due to their effective performance.
His optimistic prediction was partially contradicted by the evolution of production in oil and gas industry. Indeed, the effective number of wells horizontally drilling for oil and gas surpassed the quantity of vertical or directional wells, but that happened only in March 2010. Nowadays, almost two-thirds of global oil and gas production is drilled through horizontal wells, according to the latest reports issued by Baker Hughes, an oil field services company.
The decade 1993-2003 was an intense period of experimentation. For example, George Mitchell representing Mitchell Energy developed an impressive research activity in Barnett Shale in Texas, testing the efficiency of mixed horizontal drilling and hydraulic fracturing procedures.
Based on the results obtained in Texas` area, the oil companies drilling in North Dakota implemented similar procedures, generating impressive productions.
In 2003, the implementation of horizontal wells reached its peak. Commonly, this type of wells has widely replaced the old vertical or directional wells, since they could reach faster and more efficient the required reservoirs.
The revolution was clearly described by Schlumberger, mentioning that with the help of horizontal wells, exploitation will effectively generate the results imagined by companies involved in oil and gas industry. In addition, those who would ignore the new technique, will have to admit in a short period of time its most visible advantages: deeper drainage aimed to reservoirs, reduction of gas and water loss.
Some analysts believe that the effective shale revolution started in Texas, at the beginning of the 21st century, but in fact the genuine revolution debuted a decade earlier.
For example, researchers interested in horizontal drilling develop their studies starting with 1980s, as consequence it can`t be considered a phenomenon emerging in the 21st century.
The confusion is additionally fuelled by skeptical commentators, arguing that there are good oil or gas obtained through fracturing, as well as bad materials, a distinction that can`t be scientifically supported.
The history of the techniques described below highlighted that there aren`t good or bad strategies, only methods correctly applied to a particular area.
In this context, both fracturing and horizontal drilling were widely implemented in either conventional or unconventional exploitation, depending on several inner factors.
Concretely, methods of extracting oil or gas in conventional exploitation areas were implemented also in unconventional areas. As well, the opposite situation is largely encountered, as consequence a clear distinction can`t be issued.
As seen, the historic transformations of fracturing and horizontal drilling proved that the creation and implementation of new technologies is a long and quite difficult process. Everything that is new in oil or gas industry has to be intensively tested in terms of efficiency and largely promoted, so that it became popular worldwide.
As consequence, if there are new techniques to revolutionize oil and gas industry, they need to draw attention in a local context, to prove their efficiency there, so that large communities can discover them and implement them worldwide.