While fighting off critics with his left hand, King Hubbert continued research and writing with his right. The following are sketches of some of his papers before and after the bell ringing (not necessarily in chronological order).
✓ During his time at Columbia University, Hubbert worked summers for the Illinois Geological Survey, dealing primarily with ground waters. In 1940 he published a paper dealing with “The Theory of Ground-Water Motion” in The Journal of Geology.
Hubbert was interested in the longheld theories and laws developed in the 19th century by Henry Darcy. Hubbert replicated Darcy’s original experiments, which led to the publication of this paper – which verified Darcy’s work, but also included the field equations for the movement of water and other fluids through porous media.
His paper established the foundation for modern hydrology, although at the time the paper did not attract much attention, and in a few months was out of print. Ten years later it was reprinted, but wasn’t widely known.
By chance in 1968, at a publishing house booth at a technical convention, a book publisher recognized Hubbert and asked him for permission to publish his paper in book form. When this paper resurfaced, it attracted the attention – and often the ire – of a new generation of scientists.
According to Hubbert memorialist David Doan, it “infuriated the hydrologists and petroleum engineers, who ceased fighting each other to turn on him. He took on all critics in published rebuttals that are themselves models of reasoning and clarity.”
Hubbert gloried in intellectual combat.
✓ Later in 1940 Hubbert worked for the World War II Board of Economic Warfare in Washington, D.C.; then in 1943 he came to work for Shell as the director in the Bellaire Research Lab in Houston, and soon began contributing to operating research.
When he was working in the Illinois Basin he observed the oil-water relationships in several relatively small fields. When the ground water was static, the contact between the water, oil and gas was horizontal; but when the ground water was in motion, the contacts would slope at some angle down-dip depending on the strength of the flow.
As a consequence, some fields were slightly offset to the structural high.
Recognizing that the hydrodynamic phenomenon might offer a competitive advantage, Shell selected a number of its geologists to study this phenomenon under Hubbert’s direction at the lab. The Rocky Mountain basins seemed ideal for application of this concept.
While several fields did exhibit this situation, no new fields or extensions were discovered in that area.
However, one of the geologists selected for Hubbert’s course applied these techniques to the Permian Basin, which assisted the discovery of several hundred million barrels of oil. In other areas, the studies helped to quantify the requirements for effective permeability barriers for stratigraphic traps and field development, particularly for secondary recovery projects.
Since the technique required data from wells of other sources, the technology soon became widely known. Recognizing the importance of the application, Hubbert was invited to undertake a Distinguished Lecture tour in the United States on this subject.
Later in 1967, Hubbert gave an invited paper titled “Application of Hydrodynamics to Oil Exploration” at the seventh World Petroleum Congress.
✓ In 1948 a paper by J.B. Clark, a petroleum engineer with Stanolind Oil and Gas, introduced the technique of hydraulic fracturing of selected portions of a potentially productive zone that might be improved by a stimulation process. The process would be to isolate this zone and inject a fluid such as diesel under high pressure, which would fracture the formation or widen fractures, which already existed.
“Fracking,” for the most part, proved very successful, and between 1948 and 1955 over 100,000 individual treatments had been performed. Advertising by companies performing fracking services showed that the fracking was horizontal.
However, a number of petroleum engineers had questioned whether the fractures were really horizontal. To produce a bedding plane fracture meant that the entire weight of the overburden would have to be overcome. In the fluid injection process, it was self-evident that fracturing had indeed occurred, but was it horizontal or was it vertical? Hubbert and David Willis began research on the mathematics and modeling of the fracturing phenomenon. The results of this 1956 study, “Mechanics of Hydraulic Fracturing,” showed that in tectonically relaxed areas, such as the Gulf Coast, the principal stress was vertical (overburden), and the fracture would also be vertical. When the principal stress is horizontal from tectonic pressure, the fracturing will be horizontal, as the bedding planes will be less tightly compressed.
This new information was of great economic significance in field development and particularly in secondary recovery projects.
This required some changes in the service company’s advertising brochures.
An interesting non-oil variation of this phenomenon occurred in a disposal well in Colorado.
In 1962, the northwest region of Denver experienced a series of earthquakes; at 5.3 on the Richter scale these were not seriously damaging. But they rattled a few dishes and became of concern to the public, who feared it might portend a “big one.”
The Rocky Mountain Arsenal is located in the north suburbs of Denver, and during World War II had manufactured and stored nerve gas cylinders. After the war, a commercial company utilized the facilities in making pesticides. The Arsenal and the chemical company were pumping waste fluids into this 12,000-foot disposal well.
Faulting was well known along the Front Range. David Evans, an independent geologist, had heard Hubbert’s lecture and read his paper on the hydraulic fracturing of rocks, and he suggested that this procedure might be activating the faults causing the earthquakes.
Recognizing this might be a possibility, the governor, acting on Evans’ theory, ordered that the pumping be stopped and requested the Colorado School of Mines to study the problem.
Expert geologists and geophysicists studied both the ground and underground conditions. Cores taken at the time of drilling showed that the well bottomed in the Precambrian. The oldest formations were of a melange of metamorphic and igneous rocks. The latest of the faulting was a north-south strike-slip fault of the Laramide Age.
Apparently the injection caused “loosening” of the welded rocks, allowing movement, which triggered the earthquakes.
The interesting phenomenon was the seismic “chatter” of minor faulting. In 1965 there were 550 small quakes, and from 1962-67 there were 1,514. After the pumping ceased, there were some residual pressure releases as the elements normalized and the quakes eventually ceased.
Throughout his professional career, King Hubbert was a prolific writer for 58 years from 1927 to 1985, producing 60 titles from the fundamental to the esoteric, inlcuding:
- 1927 – A suggestion for the simplification of fault descriptions.
- 1937 – Theory of scale models as applied to the study of geological structures.
- 1967 – Critique of the principle of uniformity.
- 1971 – Role of geology in a maturing industrial culture.
- 1974 – Statement of relations between physical growth rate, the monetary interest rate and inflation.
- 1981 – The World’s evolving energy system.