A SHORT HISTORY OF HYDRAULIC FRACTURING
- Written by Prof. Constantin Cranganu
One might rightfully say that the history of hydraulic fracturing started with the first drilling for oil by Edwin L. Drake, best known as Colonel Drake (he had never been a colonel, just a railway conductor, but the term colonel imposed respect).
In 1856 Seneca Oil Company in Pittsburgh, Pennsylvania started producing kerosene (lamp oil) by refining the petroleum collected from an oil spring in neighbouring Titusville. The surface spill was not enough for a refinery. Edwin L. Drake was hired by Seneca Oil in 1858 to investigate suspected oil deposits by drilling in the manner of salt well drillers. On August 27, 1859 Drake’s drill reached 21 meters depth. As it was Saturday, work was stopped. The next day crude oil was rising up in the hole. That is how it started the history of a new form of energy that would revolutionize the development of human society with consequences this very day.
Edwin L. Drake failed to patent his drilling invention. He did not posses good business acumen and died in 1880 as an impoverished old man, 22 years after his invention gave birth to a new era of prosperity generated by the use of oil derivates (gasoline, diesel fuel, kerosene, plastics, chemical products and pharmaceutical products, etc). Edward A. L. Roberts came to Titusville several years after “Colonel” Drake. When he died, (one year after Drake) he was one of the richest people in the US at the time. As Drake can be considered the father of oil drilling, then Roberts may be considered the father of hydraulic fracturing. He invented the “Roberts torpedo”.
During the American Civil War Roberts was a lieutenant-colonel with the Unionist army. Together with his regiment, he took part to the Battle of Fredericksburg, Virginia. During the massive attack supported by the Confederate artillery he made an interesting discovery: he came up with the concept of using water to “tamp” the resulting explosion of shells, after watching Confederate artillery rounds explode in a canal. Roberts thought of implementing this principle to the oil drillings in Pennsylvania by placing an explosive device on the bottom of a well filled with water. The water would tamp horizontally the bedrock instead of acting vertically.
Roberts torpedo was the very first device of rock fracturing. He brought six bombs to Titusville. Torpedoes consisted of canisters filled with gunpowder and automatic percussion cap. Workers lowered the torpedo into the well with a long wire. One on the bottom, a metal piece, more like the weight of the fishing rod, was lowered on the wire, hitting the percussion cap to detonate the gunpowder. Roberts patented his invention in 1866.
The new method had a considerable success for new wells as well as for the old ones, with low production. Soon enough gunpowder was replaced by nitroglycerin. Local newspapers raced to praise Roberts’ invention: “For the past three years, it has been a most successful operation, and has increased the production of oil wells in hundreds upon hundreds of oil wells at an extent which could hardly be overestimated. Next to the discovery of oil, no invention has done more to enrich well owners than the Roberts torpedoes.”
After torpedoes, the next important step in extracting oil from the bedrock took place in 1932, when Dow Chemical started using hydrochloric acid to dissolve the rocks and dig channels for the oil. The first test took place in Midland, Michigan, near the headquarters of the company. The Dow Chemical engineers mixed 500 gallons (about 1,900 litres) of acid with arsenic in order to prevent the steel pipes’ corrosion. The new procedure was a success, as the oil production increased threefold. Next year, in northern Texas, another company decided to inject pressurized acid into the wellbores. This time 750 gallons (about 2,800 litres) of acid were used, followed by crude oil in order to force the acid into the limestone. Before applying the procedure the well was producing 1.5 barrels a day. After the procedure the production increased almost 80 times to 125 barrels a day! (one barrel = 159 litres). By 1938 some 25,000 drillings were treated with acid, in some cases 10,000 gallons of acid being used (one gallon = 3.78 litres). Nevertheless, the use of acid has limited applications because it is successful only in the case of calcareous rocks with high concentration of calcium which is eliminated after the reaction with the hydrochloric acid. The method’s limitations have raised serious problems, as most oil reserves are formed in sandstones and the acid has no reaction. The engineers needed to find something else to crack the rocks and increase the wells’ production. The next step in the hydraulic fracturing history took place in Tulsa, Oklahoma, self-proclaimed ‘world capital of oil’ (not without reason: in 1917 the American Association of Petroleum Geologists - AAPG, the most important professional organization of oil geologists in the world, was formed there; the association is publishing high-level professional magazines such as AAPG Bulletin; in 1930 the Society of Exploration Geophysicist - SEG, the most important professional organization for oil geophysicists in the world, was also formed there: SEG is the publisher of Geophysics and The Leading Edge magazines).
The prominent local company in Tulsa was Stanolind, set up in 1911 after the Supreme Court ordered the split of John D. Rockefeller’s empire (Standard Oil). Stanolind (later Amoco and then part of the British Petroleum) has had independent research units, a similar network being available only to two other companies: Texas Oil Company, later Texaco and Standard Oil Company of New Jersey, later Exxon.
One of the younger engineers working for Stanolind after WWII was Riley “Floyd” Farris. His specialty was cementing the wellbore. Then, as now, the drillers were using cement to fill the empty spaces between the pipe tubing and between the external tubes and rock formations. Through cementing the well becomes anchored on the rock. If the drilling is passing through water-bearing layers (groundwater or drinkable aquifers), the cement is sealing the well (no water invades from the rock into tubing) and vice versa, it is sealing the aquifers (the water is not contaminated by the fluids from wellbore).
Farris was intrigued by a mystery old oilmen could not solve. They had noticed that once the cement is going into the well, part of it was vanishing. As cement was not cheap at the time (nor it is today) due to the losses, the drilling costs were rocketing. Some drillings needed up to five tanks of cement more. What was going on? Why do some wells ‘swallow’ more cement than the calculations anticipate? Where was the cement going to?
Farris carried out systematic studies on 115 well files and, by correlating the pressure exerted by the cement’s weight with the drilling depth, he reached the conclusion: the cement’s weight and other liquids’ weight were crashing the rocks causing fracturing. When the cement is pumped down the well, part of it was going into the fractures. What if he would try to fracture the bedrock by pumping liquid? Unlike the cement, the liquid could be taken out of the wellbore after fracturing the rocks. Once the liquid is removed, maybe more oil and gas would leak out of the bedrock, he thought.
One of Farris’s colleagues, Bob Fast, 25, decided in November 1946 to verify the hypothesis of fracturing the bedrock by injecting liquid. His experiment took place in Klepper #1 well on the Hughoton gas field in south-west Kansas. Colonel Roberts operated the fracturing with explosives, while Fast and Farris operated the first fracturing with liquid. As water involved friction and implied using several pumps to inject it into the bedrock, Fast was looking for a way to reduce friction. He needed a liquid to play the role of lubricant (having low viscosity) and to get mixed with water, while not being scarce. Fast had chosen napalm, leftover from WW II, when it had been used for flame throwers and incendiary bombs dropped over Japan.
Fast pumped into the well 1,000 gallons (3,780 litres) of gasoline thickened with napalm, followed by another 2,000 gallons (7,650 litres) of gasoline. He repeated the procedure four times at different depths. He claimed he fractured the limestone. When the napalm and the gasoline were recuperated, the gas erupted from the well. However, it was the same quantity of gas as the one obtained by using the hydrochloric acid (the conventional method to acidize the well). The first attempt for fracturing proved to be a failure.
The research carried out by Stanolind was named ‘hidrofrac treatment’ and it wasn’t meant to serve only pure science. The company wanted to make the wells more productive. By the middle of the 20th century, finding rich oil and gas fields had become a major problem for the US companies. They were drilling less and wanted to exploit the last drop of oil from the bedrock. The oil companies had invested huge amounts of money in drillings and in building the pipelines to transport oil and gas, so any kind of technology to increase production even by 5 percent could have been profitable. During WW II the steel was used for building tanks, canons, machine guns and other military devices. A deep well (for example 1,300 metres) needed 61 tons of steel for drill pipes and tubes. The oil industry faced a dilemma. It needed to increase production to meet the war demands, but could use limited quantities of steel. They turned back to the old wells, abandoned due to low production. Until the ‘40s the American companies had drilled more than one million wells. More than half of them had no more production or insignificant ones. Fast and his colleagues believed fracturing could bring back to life the old wells, while new wells could become more productive.
By carrying on the lab research and research on models in the field, Fast and Farris succeeded in proving the reservoir bedrock could be fractured with cement. They also realized that using water raised a problem. Why not use the water mix with sand to maintain the fracturing open, they asked themselves? The first attempt took place in eastern Texas in a well producing less than one barrel a day. A mixture of sand, oil, soap and metals was pumped into the well and kept there for 48 hours. The soap washed away the oil from the bedrock. After the mixture was taken out, the well started producing 50 barrels a day. The production, 50 times larger, continued for a long time (several months).
Farris submitted a request for patent for hydraulic fracturing in May 1948. The license was granted to HOWCO, Halliburton Oil Well Cementing Company.
The hydraulic fracturing began evolving fast. By the middle of the ‘50s the drilling companies had begun using more water and less chemical additives as fracturing liquid. It was recommended to avoid using water as it could affect the underground deposit and could affect oil and gas extraction. The first test on the field infirmed these preconceived ideas and higher quantities of water were used, becoming common practice. More than that, injection rates increased 20 times, pumping more fluid to put higher pressure on the bedrock and lead to more fractures. New innovations helped the pumping equipment add more horse-power to the hydraulic fracturing. Bob Fast and his colleagues at Stanolind continued to research hydraulic fracturing for many years. The company became interested in using more powerful explosives made up by rocket fuel in order to get more fractures. This idea proved fatal. On November 11, 1970 a team drilled a well to test the fuel as fracturing liquid. A piece of equipment was coupled to an electric line and accidentally led to an explosion. Eight workers were killed on the spot. Fast was not at the site, although he used to supervise the works. He was on a leave. Two years after the accident he retired.
By 1959 the oil industry had become interested in using nuclear energy. It was proposed to use atomic bombs to fracture the wells. Edward Teller, the father of the Hydrogen bomb, organized a meeting that year at Lawrence Radiation Laboratory – now Lawrence Berkeley National Laboratory, to discuss the peaceful using of nuclear energy. Teller suggested it could be used for mining and excavations. The US Atomic Energy Commission agreed and set up Project Plowshare, named after the biblical verses of Isaiah (2.4): “and they shall beat their swords into plowshares, and their spears into pruning hooks”.
The program focused at the beginning on using the ‘friendly atom’ as a gigantic excavator. Proposed uses for nuclear explosives under Project Plowshare included widening the Panama Canal, and to create an artificial harbour in Alaska. None of the proposals went through due to technical issues and concerns regarding the environment. An agreement has been nevertheless concluded for cooperation between the government and El Paso Natural Gas company. Scientists co-opted in the Plowshare project wanted to find out if using nuclear explosions for bedrock fracturing is possible and cost efficient.
In 1967 scientists detonated a 29 kiloton bomb somewhere near Farmington, New Mexico. Hailed by political leaders and state officials, the bomb had been lowered 1,200 metres into a well dug in clayey bedrock, which resulted in a 50 metres diameter cavity. Called Project Gasbuggy the detonation was a success, but the resulting gas contained a too high level of radioactive Tritium and other isotopes. Researchers decided to test a more powerful bomb, aiming to produce more gas and recoup the millions of dollars invested in creating the bombs. The next blast was called Rulison, after a town in Colorado. It had a power of 43 kilotons and exploded deeper in the well. (For comparison the bomb dropped at Hiroshima had a power of 13 kilotons). The Rulison bomb was detonated in September 1969, after the end of Woodstock festival. Measurements indicated the bedrock had been fractured on a radius of 76 metres. When the gas began to flow into the well it had high quantities of Tritium and Kripton-85. The Atomic Energy Commission carried studies on people’s exposure if the gas would have been pumped through pipelines to the population. Two cities would have received the highest dose of radiation from burning gas in the kitchens and in the fireplaces, Rifle and Aspen (a US ski resort en vogue). The dose would have been low, but it concerned only one well.
These attempts to crack the bedrock to extract hydrocarbons drew the attention of the White House. During a speech delivered in 1971, President Richard Nixon said that finding increased quantities of natural gas will be one of the most urgent energy needs for the following years. He expressed support for nuclear simulation tests to produce natural gas from geological compact bedrock that could not be exploited at the moment. Getting the high-level go-ahead Project Plowshare continued. The next test had included the simultaneous detonation of three bombs, each one bigger than the one used for Gasbuggy. They were placed afar so that the impact area would create a huge vertical gas column. The project’s supporters believed the method would solve the energy deficit for the US. They were hoping nuclear fracturing would become a common technology to be used every day and anywhere a gas well is drilled. The Rio Blanco explosion was detonated in western Colorado in May 1973, during a period of time when the market faced low natural gas supply. Two months ago the energy crisis had hit a soft issue, as state schools in Denver, Colorado were closed due to lack of heating gas. The nuclear blast sponsors released an informative bulletin – The Rio Blanco News – announcing in its first issue that “the Rio Blanco gas could mean 10 years of reserves for the US”. The optimism was not confirmed by the blast’s results. The three bombs created individual vertical columns, unconnected. The gas flow came only from the above blast. Instead of ten-year reserves the main inheritance remains an official plate on the site warning against digging or drilling the soil without the governmental approval.
Not getting intimidated, the Project Plowshare planners became even more ambitious. The next test, called Project Wagon Wheel, involved 500 kiloton devices. This was only the beginning. If successful, the Atomic Energy Commission and El Paso company were planning some forty-fifty blasts a year in south Wyoming (Pinedale area). However, this time they found their match. Locals got organized to put the project to a halt. People were concerned by the impact of ground shaking on local roads and irrigation network. The economic part of using nuclear bombs was put under scrutiny. The Energy Department subsequently said USD 82 billion was spent for the project and even if the gas would have flowed for the next 25 years the amount was not to be cleared off.
It is unclear how Project Wagon Wheel was cancelled, but Wyoming’s lone congressman, Democrat Teno Roncalio played a decisive role. In January 1973 he had been appointed with the Congress’s Joint Committee for Atomic Energy. One week later he announced that the funds for Project Wagon Wheel had been cut from the federal budget. In 1978 he decided not to run for re-election. An opportunity showed up for a young Republican. He would win the elections and was to play a major part in developing of the hydraulic fracturing as chief executive officer (CEO) of Halliburton. His name was Dick Cheney.
As interest for hydraulic fracturing vanished, the concerns for energy security have increased. In November 1973 President Nixon vowed to eliminate oil imports by 1980. It was to no avail. He resigned in August the following year.
The natural gas reserves have diminished to such a degree that the Congress adopted in 1978 a law calling illegal the building of gas-fired power plants. Until the law was repealed nine years later by President Ronald Reagan, the US had built many coal-fired power plants that were supplying 81 GW power. Almost one quarter of those coal plants are still working. The government officials had no choice. The newly discovered gas fields had low production volumes, about four out of every five wells proved to be unproductive.
Facing an unfolding energy crisis, the government was looking for solutions. Efforts were made to reduce energy demands. Speed limits were lowered to save gasoline and diesel fuel. Attempts to stimulate energy offers were made. A less known program could be included in these attempts: Unconventional Gas Research Program – UGR. The funds for the program were relatively low – USD 30 million was its best year. Starting in 1977 and continuing in the following years, most of the funds went to the research unit in Morgantown, West Virginia, which was carrying studies on shales in the Appalachian Mountains. The energy industry was aware of the gas reserves in the shale layers, but the drillings were made at shallow depths and production was unpredictable. The energy companies drilled only those shallow strata that could be naturally fractured. UGR wanted to change the situation. Geologists were sent to the sites in the region to study the shale layer characteristics. Furthermore, several wells were drilled. UGR attempted fracturing by chemical blasts and even by congealing the bedrock using cryogenic substances.
Al Yost was one of the most talented researchers being included in the UGR program. Over more than ten years he tested lots of new technologies that would represent the framework for developing the hydraulic fracturing. In order to study its consequences Yost and his engineers colleagues placed minuscule cameras inside the wells to understand what was going on down there and used seismic waves to chart the resulting fractures. For the first time they tested massive hydraulic fracturing – a technology that would become common only 20 years after being tested by Mitchell Energy company.
The next step in hydraulic fracturing history was to be written in Texas and Oklahoma.
George Mitchell graduated as oil engineer the Texas A&M University and settled in Houston in 1946. Together with his brother Johnny he started an oil exploration company. In 1952 he drilled the first well - D. J. Hughes #1 – and found gas (sixty years later the gas was still flowing out of the well). The next ten wells were productive as well. Mitchell got excited. Boonsville Bend, the area where he registered success, was part of the Dallas - Fort Worth metropolis. He rushed to lease land up to 130,000 hectares. Following the promising start, Mitchell thought luck would not last long. He was convinced that finding new oil and gas reserves requires sound scientific and technological knowledge. Finding out that Stanolind had successfully used well fracturing, Mitchell did not hesitate. He immediately started to fracture his new drillings in Boonsville Bend area. Economic accomplishment did not linger and his new company – Mitchell Energy – became a spectacular success.
In June 1982, upon Mitchell’s insistence, his engineers had fractured the bedrock in the Boonsville Bend area – the Barnett shale. Several years ago a governmental program tested massive hydraulic fracturing in a well close to Mitchell’s leased land. A mixture of water and oil as gelatinous emulsion called ‘Super K-frac’ was used. The pressure broke the drilling column and a 1,600 metres deep cavity resulted. A month of labour was needed to localize the rupture and cement it. Pessimistic reactions surfaced: a governmental official wrote in his report that “probably this approach is not economically efficient.” Mitchell chose another fracturing method: he poured 42,000 cubic metres of nitrogen in the wellbore. Then, in 1983, he tested again fracturing by using carbon dioxide and water. The main result? The fractured shale produced almost 7,000 cubic metres per day, a non-convincing result. For comparison, nowadays a fractured well in the Barnett shale could produce about 142,000 cubic metres of gas per day.
The Mitchell Energy company’s researches continued by testing new types and by using various quantities of fracturing fluids. One acute problem was the fracturing fluid type. Hydrochloric acid was effective only if the bedrock was made up of calcium that was dissolved by the acid. When using gelatinous emulsions, part of the emulsion was effectively blocked within the bedrocks’ pores, reducing the permeability needed to increase the gas production.
Nick Steinsberger, one of the engineers with Mitchell Energy, had a revolutionary idea: using water instead of the emulsion. Large quantities of water: four to five times more water than in case of the emulsion. On June 11, 1998 he carried out the first fracturing with water at the S.H. Griffin #4 well in the Dallas - Fort Worth area. He used twenty tanks of water and twelve powerful pumps to open the bedrock pores. Two tanks supplied the chemical additives: a friction reducing gel to make water more slippery and a bactericidal substance to kill micro-organisms that could have got into the waste liquid.
No less than one million gallons (3.78 million litres) of water were pumped. After one hour, fine sand was pumped. The water column had 2,500 metres, making an enormous pressure on the bottom of the well on the Barnett shale. Steinsberger was nervously awaiting the following days to see the results of the first fracturing using water. The results were astonishing: while normal wells were producing 1-2 million cubic metres of gas during the first 90 days of production, the S.H. Griffin #4, massively fractured with water, produced in the same interval 3.3 million cubic metres.
The S. H. Griffin well, fractured fifty two years after Stanolind had tested the first ‘hydrafrac’ marked a landmark on the way of claiming the hydraulic fracturing as the most important technological discovery of the latest decades.
Figure no. 1: The distribution of hydraulic fractured wells in the Dallas – Fort Worth area. One can see that by 1997 there were only two horizontal drillings. (Source: http://www.barnettshalenews.com/documents/2012/pres/Evolution%20of%20Barnett%20Shale%20by%20Nick%20Stei)
Figure no. 2: The distribution of hydraulic fractured wells in the Dallas – Fort Worth area by 2012 (15 years since using the horizontal drilling). All drillings are horizontal. Source: http://www.barnettshalenews.com/documents/2012/pres/Evolution%20of%20Barnett%20Shale).
Thousands of wells have been fractured with water (compare the drillings map in 1997 – Figure no. 1 – with the one in 2012 – Figure no. 2). It is estimated that the method introduced by Nick Steinsberger generated some 283 billion cubic metres of gas.
In 2002 Mitchell Energy was bought by Devon Energy, a company based in Oklahoma City. The engineers working with Devon (Steinsberger among them) have come up with another revolutionary idea: the horizontal drilling. Until then all drillings were done vertically. The Barnett shale layer is typically 100 metres thick. A vertical drilling opens the bedrock only for this depth range. In exchange, the horizontal drilling could extend the fracturing operation for a larger distance (up to 2 km or more). Using a single entrance shaft they could drill, one after another, six to eight horizontal wells. The surface of fractured shale increased dramatically, while cutting down the drilling costs due to using single surface equipment that would drill horizontally in several directions. Another advantage of the horizontal drilling into the Barnett shale is a geological one: the Barnett shale is underlain by the Ellenberger formation filled with salty water. Vertical drilling would risk penetrating the Ellenberger formation accidentally and losing the fracturing liquid as a consequence.
Horizontal drilling (Figure no. 3) had become, meanwhile, faster and more accurate due to technological innovations of the drilling operations, as well as for geophysical logging meant to direct and control the direction and the positioning of the wellbore. In June and July 2002 Devon drilled its first horizontal well (Veale Ranch #1H) into the Barnett shale. The well was then fractured using 4,500 cubic metres of water. In October the same year Devon performed a second horizontal drilling, Graham Shoop #6. After 2002 horizontal drilling has become standard procedure for wells exploiting shale gas by hydraulic fracturing. Comparison between Figure 1 and 2 is showing the amplitude of horizontal drillings.
Figure no. 3: Comparison between the vertical drilling in the Barnett shale and the horizontal drilling operated by Devon Energy in 2002. The Ellenberger formation (filled with salty water) is represented under the Barnett shale. Source: http://www.horizontaldrilling.org/).
I would like to add one last comment about the impact of hydraulic fracturing of the Barnett shale in the metropolitan area Dallas – Fort Worth, where some 6.8 million people live (about one third of Romania’s population). Various Romanian sites have published stupid information: the Americans can afford to operate hydraulic fracturing because they are doing it in the desert and low populated areas!!! The truth lies on the opposite of this nonsense: the using of modern type of hydraulic fracturing has started and is continuing in the Dallas – Fort Worth area. For those still believing hydraulic fracturing is operated in the desert, please look at the map in Figure no. 2 (try to count the drillings operating in the Dallas – Fort Worth area) and then look at the picture below (Picture no. 4) with one well placed downtown Fort Worth, Texas.
Picture no. 4: Fourth Street 'A' Gas Unit #1H, East Downtown Fort Worth, Texas, 6 October, 2006, Courtesy of Dale Operating, Photo by Mike Fuentes.
The last page (for the moment!) of our short recent history of the hydraulic fracturing in the US was written by Halliburton, which has recently introduced a new fracturing fluid called CleanStim , having as components ingredients used by the agri-food industry. By using ingredients from the agri-food industry it is offered a supplementary safety margin for people, animals and the environment in the less probable incident at the well. In order to prove the new fracturing liquid is harmless to the people, Dave Lesar, CEO of Halliburton, together with John Hickenlloper, the governor of Colorado, drank a sip of liquid during a meeting held on November 30, 2011 . The governor testified in front of the US Senate: “It was not terribly tasty, but I'm still alive.” On its website, Halliburton is not advising people to drink from the new fracturing liquid.
The Baker Hughes company , one of the most important operating the oil service field, including hydraulic fracturing, had recently placed gladdening news on its site: “Baker Hughes believes it is possible to disclose 100% of the chemical ingredients we use in hydraulic fracturing fluids without compromising our formulations – a balance that increases public trust while encouraging commercial innovation. Where accepted by our customers and relevant governmental authorities, Baker Hughes is implementing a new format that achieves this goal, providing complete lists of the products and chemical ingredients used.”
Paula Gant, Deputy Assistant Secretary for Oil and Natural Gas in the US Department of Energy’s (DOE) said that the decision taken by Baker Hughes is “an important step towards building public confidence” and that the department is hoping others could follow this example. Halliburton, Baker Hughes’ main competitor, said it is interested in protecting “our intellectual property and the substantial investments it represents” and would examine the new Baker Hughes format for its capacity to protect such investments.
The history of hydraulic fracturing, started in a town in Pennsylvania by the middle of the 19th century, is interspersed with the continuing research efforts of the American engineers and researchers to find the most performing technological solutions necessary to take advantage of the new form of energy – the shale gas.
(Excerpts from the volume in preparation “Hydraulic fracturing, between myth and truth”)
Gold, Russell, 2014, “The Boom How Fracking Ignited the American Energy Revolution and Changed the World”, Simon & Schuster
Constatin Cranganu is a professor of geophysics and petroleum geology at the Graduate Center and Brooklyn College of The City University of New York. During 1980 - 1993 he was an assistant professor of geophysics at the ‘Al. I. Cuza’ University in Iasi, the Faculty of geography-geology. In 1993 he won the first national contest in post-communist Romania of the prestigious Fulbright scholarship offered by the US Congress. As Fulbright Visiting Scientist at the University of Oklahoma he carried out fundamental and applied research regarding oil and natural gas deposits, overpressure in the sedimentary basins, heat flow and radioactive heat, identifying gas-bearing layers in the wellbore, exploiting unconventional deposits of gas hydrates through a personal method, etc. After moving to the City University of New York in 2001, Professor Cranganu started research in a new direction: implementing the methods of artificial intelligence in the petroleum and gas studies. For his work in this pioneering field he was nominated to ENI Awards in 2012 and was offered by the Springer publishing house to publish a book by 2015 (“Artificial Intelligent Approaches in Petroleum Geosciences”). His most recent book is titled “Natural Gas and Petroleum: Production Strategies, Environmental Implications and Future Challenges”, published by Nova Science Publishers, New York in 2013.