The Technological Improvements that Produced the Shale Revolution
This piece ,Sizzling Rocks: Commercializing Subsequent-Technology Geothermal Power, SIFgeothermal energy abundantis part of Hot Rocks: Commercializing Next-Generation Geothermal Energy, a joint series by Employ America and the Institute for Progress, inspecting the potential to commercialize next-generation geothermal vitality, the teachings we’d be taught from the shale revolution, and the federal coverage modifications wanted to make it occur. The introduction to the sequence is out there here, with hyperlinks to obtainable follow-up items.
Within the technique of shifting to wash, agency sources of vitality, one promising know-how is geothermal. Traditionally, geothermal energy may solely be produced in locations the place water naturally strikes by heated rock close to the earth’s floor, like hot springs. This meant that geothermal energy vegetation may solely be inbuilt a small variety of locations, and as of 2022, solely about 0.4% of the US’s electricity got here from geothermal energy.
However warmth from the earth is out there anyplace, if you happen to can drill deep sufficient and discover a technique to extract it. Most of the geothermal vitality applied sciences being developed immediately may very well be constructed nearly anyplace. The quantity of warmth vitality within the earth’s crust is so enormously vast (41x greater than that of all recognized petroleum and nuclear gas reserves) that large-scale building of geothermal vegetation may present an considerable supply of zero-carbon vitality, with out the intermittency problems of photo voltaic and wind.
New approaches make intensive use of drilling know-how initially developed for the oil and gasoline trade. As simply obtainable sources of petroleum and pure gasoline have been exhausted, the trade regarded to develop drilling strategies to economically faucet much less accessible deposits.
Hydraulic fracturing, or fracking, was developed within the Nineteen Nineties to extract pure gasoline from beforehand inaccessible shale deposits. Because of fracking, shale gasoline went from 2% of US pure gasoline manufacturing in 1998 to nearly 80% of American pure gasoline manufacturing by 2022. In the present day, next-generation geothermal firms are utilizing superior drilling and fracking applied sciences from the oil and gasoline trade. Maybe sarcastically, know-how developed for the oil and gasoline trade may very well be essential in our effort to transition to zero-carbon sources of vitality.
Till the Nineteen Nineties, most pure gasoline within the US was extracted by drilling a nicely right into a pure gasoline reservoir, a big crack or area between layers of rock the place pure gasoline had collected. In one of these pure gasoline deposit (referred to as “typical gasoline”), the gasoline will readily flow into the nicely.
However pure gasoline may also be discovered throughout the pores of some rock formations, comparable to shale layers. These so-called “unconventional” gasoline deposits had lengthy been recognized about, however the rock’s low permeability restricted gasoline extraction. This modified within the Nineteen Nineties, when Mitchell Energy developed novel fracking methods to extract giant quantities of gasoline from the Barnett Shale in Texas. By injecting high-pressure fluid into its gasoline wells, the rock under the floor would fracture, rising its permeability and thus the circulation of pure gasoline. These cracks could be saved open by infusing the fracking liquid with “proppants,” small sand-like particles that had been carried into the cracks and prevented them from closing.
Fracking itself was not a brand new know-how within the 90s. Its use in oil and gasoline dates again to 1947 and the Stanolind Oil and Fuel Firm. On the time, Stanolind injected acid into its wells to widen the pores within the rock and improve nicely manufacturing (a way first developed in 1895, and still used today). A Stanolind engineer, Floyd Farris, observed that the upper the stress the acid was injected at, the extra the nicely produced. Farris speculated that the high-pressure injections is perhaps fracturing the rock, and that it is perhaps doable to extend nicely manufacturing just by injecting a fluid below excessive stress. Stanolind’s first try at hydraulic fracturing was on a pure gasoline nicely in Kansas, and used a fluid composed of gasoline and napalm blended with sand. Over the subsequent two years, the corporate fracked 23 wells, rising gasoline manufacturing in 11 of them. When Haliburton licensed Stanolind’s fracking approach in 1949, it discovered that fracking elevated nicely manufacturing by 75% on common, and went on to frack 1000’s of its wells. By 1955, over 100,000 oil and gasoline wells world wide had been fracked, and fracking had elevated the provision of oil within the US “far past something anticipated.”
Fracking know-how superior over the subsequent a long time. Early fracking used comparatively small quantities of fluid and proppant, on the order of 400 kilos of sand and 750 gallons of fluid per nicely, however by the Seventies so-called Massive Hydraulic Fracturing was injecting on the order of 500,000 gallons of fluid and 1 million kilos of proppant into pure gasoline wells. Fracking fluids developed, from gasoline and napalm, to water, to cross-linked guar gels. Completely different sorts of proppants, together with “plastic pellets, metal shot, Indian glass beads, aluminum pellets, high-strength glass beads, rounded nut shells, resin-coated sands, sintered bauxite, and fused zirconium” had been all experimented with.
By the Nineteen Nineties, fracking was a mature know-how, utilized by Mitchell Power for a few years. Mitchell had drilled wells into the Barnett Shale since 1981, after an worker revealed a paper suggesting that the Barnett may comprise giant quantities of oil and gasoline. By 1995, Mitchell had drilled greater than 250 wells within the Barnett, experimented with totally different fracking fluids and chemical substances, and had carried out large fracks to stimulate nicely manufacturing with as much as 3 million kilos of proppant and 1 million gallons of fluid. However manufacturing charges on Barnett wells remained unimpressive.
Mitchell’s breakthrough got here in 1997. On the time, Mitchell, like many of the trade, was utilizing viscous cross-linked gels. After one gel frack, Mitchell engineer Nick Steinsberger observed that the gel had not correctly set, making the fluid related in consistency to water. However even with out the help of gel, the nicely was producing a shocking quantity of gasoline.
Water had beforehand been used as a fracking fluid within the 50s and 60s, however had largely been changed by gels designed to be thick sufficient to hold proppants deep into fractured rock. Later, chatting with a good friend at an trade occasion, Steinsberger discovered that Union Pacific Sources used a fracking combine in sandstone that was largely simply water and sand, with just a few added chemical substances as friction reducers. These had been referred to as “slick-water fracks.”
On the time, water was thought of an inappropriate fluid for fracking in shales. It was believed that the shales would take up the water and swell, lowering moderately than rising permeability. Regardless of this, Steinsberger started to surprise if water may work in addition to gel as a fracking fluid in shale. As a result of it used fewer chemical substances and proppants, a slick-water frack could be less expensive than a gel frack.
After studying extra about Union Pacific’s strategies, Steinsberger started to check slick-water fracks on wells within the Barnett Shale in early 1997. The fracks appeared to work roughly in addition to gel fracks, however didn’t end in significantly spectacular ranges of gasoline manufacturing. However Steinsberger tweaked his strategies, including extra horsepower to the pumps and adjusting when the sand was added. Properly efficiency improved. The gasoline manufacturing charges from slick-water fracked wells proved a lot steadier, declining much less over time than gel-fracked wells. By 1998, the corporate had switched to Steinsberger’s strategies for all of its Barnett wells, lowering the prices of fracking the wells by 50-70% and rising gasoline manufacturing.
Mitchell’s Barnett fracking acquired an extra enhance in 1999 when Kent Bowker, a Mitchell geologist who had studied the Barnett whereas working at Chevron, confirmed that the Barnett held as much as 3x as a lot gasoline as beforehand thought. The Barnett consisted of two layers, the Decrease and Higher Barnett. Till 1999, Mitchell’s wells had been drilled into the Decrease Barnett, nevertheless it started to drill wells into the Higher Barnett as nicely, typically “refracking” already-drilled wells to faucet the Higher layer. As Mitchell extra aggressively drilled wells, gasoline manufacturing within the Barnett tremendously elevated. Between 1993 and 2002, the 12 months Mitchell was offered to Devon Energy, gasoline manufacturing within the Barnett Shale elevated by greater than 20x, largely because of Mitchell’s wells.
The subsequent main evolution in fracking know-how mixed hydraulic fracturing with horizontal drilling. Many oil and gasoline deposits are in layers of rock which might be only some tens of toes thick, however that reach horizontally for miles. By drilling a horizontal nicely into these deposits, the nicely intersects a a lot bigger portion of the reservoir, rising how a lot oil or gasoline it produces.
Drilling non-vertical wells dates again to the Thirties, when unscrupulous nicely operators within the US would drill angled wells to steal oil from their neighbors. However most early directional drilling was executed within the Soviet Union. The Soviets closely developed turbodrilling know-how, which used a small motor on the finish of the drill that was pushed by the circulation of drilling mud, moderately than rotating the whole drilling meeting (known as the drillstring) from a motor on the floor. The turbo drill made it a lot simpler to steer the drillstring and drill horizontally, and over the subsequent a number of a long time continued enhancements (such because the invention of the positive displacement motor within the Fifties) tremendously superior the artwork of horizontal drilling. In 1968, the Soviets set a document by drilling a 2,500 meter-deep nicely with a horizontal portion of greater than 600 meters.
Most of those efforts at horizontal drilling weren’t significantly profitable. From aboveground, it was tough to know the place precisely the drill was, making it exhausting to efficiently intersect a skinny layer of petroleum-bearing rock. It was additionally tough to exactly management the motion of the drill. However this started to alter within the Seventies, when drill sensors that would present info whereas the drill was working, referred to as Measurement While Drilling, started to appear. Downhole motors obtained higher, as did the bendable portion of the drill housing (referred to as the bent sub), which made it doable to steer the drill extra exactly. By the top of the Eighties, horizontal drilling had turn into “economically viable,” with prices solely barely exceeding or on-par with vertical drilling.
Mitchell Power had made a number of instructive makes an attempt to drill horizontal wells within the Barnett, however manufacturing hadn’t been spectacular. This modified after its acquisition by Devon Power. Devon’s first 5 horizontal wells drilled in 2002 “outperformed something beforehand seen within the Barnett,” with manufacturing charges over 3x Mitchell’s common fee. Horizontal wells each uncovered extra reservoir space to the nicely and sometimes allowed a lot bigger frack remedies than vertical wells. Devon’s success with horizontal drilling was partly because of its intensive use of 3D seismic knowledge, a know-how which first started to appear within the Seventies, and which enabled Devon to exactly find the layers to be drilled into. Devon additionally made use of microseismic fracture mapping — utilizing sensors to document minute seismic occasions when the rock fractures to map fracture extents and higher plan gasoline subject improvement.
From the Barnett, fracking moved on to different giant American shale gasoline sources. In 2004, operators started to drill extensively within the Fayetteville Shale in Arkansas after knowledge urged it had related geological properties because the Barnett. That very same 12 months the Marcellus Shale within the Northeast started to be extensively drilled.
Drilling different shale sources (referred to as “performs”) used the identical mixture of slick-water hydraulic fracturing and horizontal drilling that had been so profitable within the Barnett. However totally different shales had totally different geological circumstances, requiring changes to the essential fracking “recipe.” The Marcellus Shale required important trial and error with totally different fluids, proppants, pumping charges, and pressures. Mitchell’s strategies ultimately managed to extract oil from shale deposits in addition to gasoline, however this additionally took important trial and error. Oil molecules are a lot bigger than pure gasoline molecules, and transfer a lot much less readily by impermeable shales, requiring modified fracking strategies.
As Barnett proved fracking may work in shale, the dynamics of incremental enchancment in trade kicked in, resulting in transformative advances over the next years. When oil drillers used horizontal drilling and slick-water fracking on the Bakken Shale in North Dakota, they discovered that extracting oil required fracking the nicely in levels — isolating one portion of the nicely, fracking it, and repeating on one other portion of the nicely. Related multistage fracking on vertical wells proved profitable when extracting oil from Permian Basin shales in 2005. Multistage fracking would even be efficiently utilized in shale gasoline wells.
As region-specific frack strategies had been being developed, drilling know-how continued to make the method extra environment friendly. Polycrystalline Diamond Cutter (PDC) drill bits, comprised of artificial diamond, started to interchange the earlier roller-cone bits, going from 15% of oil and gasoline drilling footage in 1995 to 50% in 2005 (Mau 2015 p199). With PDC bits, wells may very well be drilled a lot sooner. Pad drilling, the place a number of horizontal wells are drilled from a single pad, avoiding the time consuming setup and teardown course of for the drilling rig, additionally started to appear, and by 2014, 70% of horizontal wells used pad drilling. To additional cut back setup and teardown instances, walking drilling rigs had been developed, permitting a rig to be moved to a different nicely website with out disassembling it. Pumps and downhole motors improved, and new drilling automation and management techniques decreased put on on the bits, extending lifespan and lowering upkeep downtime.
The dimensions of fracking operations additionally continued to extend, utilizing extra bigger pumps to pump extra fluid and proppant into wells. Horizontal wells obtained longer. Whereas Devon’s preliminary wells prolonged horizontally for round 2000 toes (Steward 2007), immediately the horizontal parts of wells routinely exceed 15,000 feet and might need dozens of separate fracking stages.
The quantity of gasoline a nicely can produce and the velocity wells are drilled have each steadily elevated. Between 2007 and 2023, gasoline productiveness per drilling rig (the quantity of gasoline produced per day by all of the wells a drilling rig drilled in a given month) elevated by practically 100x within the Marcellus Shale area. Automation, scale, and smaller technological advances turned the thrilling frontier of shale fracking to a mature, dominant trade.
Enchancment in different shale fields has been substantial, though not as meteoric: Drilling rig manufacturing elevated 5x in Eagle Ford, roughly 30x within the Bakken, and roughly 12x in Haynesville.
In the present day, this oil and gasoline drilling know-how is getting used to provide geothermal vitality.
As we’ve talked about, although warmth from the earth is out there anyplace, not all over the place has water flowing naturally flowing by fractured rock that may be tapped to extract this warmth. However utilizing hydraulic fracturing, a community of interconnected fractures may be manually created in scorching rocks deep under the floor. By pumping water into these fractures (a way just like one other oil and gasoline know-how, waterflooding), warmth could also be extracted.
Utilizing fracking to create synthetic fracture networks is the objective of so-called Enhanced Geothermal Systems (EGS). EGS know-how dates again to the Los Alamos Hot Dry Rock Program of the Seventies, however has been given a boost from the know-how used to frack shale reservoirs, comparable to utilizing slick-water, multi-stage fracks in lengthy horizontally-drilled wells. EGS has additionally benefited from monitoring know-how comparable to microseismic fracture mapping to find out the dimensions and extent of the fracture community. Fervo Power examined a profitable EGS in Nevada that created a fracture community between two horizontal wells with multi-stage fracks, attaining larger fluid circulation charges (a proxy for system efficiency) than any prior EGS undertaking. Fervo particularly credits shale gasoline drilling know-how in making its EGS know-how doable:
“Leveraging know-how improvements from the unconventional oil and gasoline trade offers a pathway to unlocking new geologic sources and bettering undertaking economics in a manner that would allow geothermal builders to imitate the speedy scale-up noticed in shale improvement over the previous twenty years.”
Oil and gasoline drilling know-how can also be getting used to develop different kinds of geothermal vitality techniques. Eavor, as an example, is utilizing directional drilling mixed with drilling a number of laterals from a single vertical nicely to create closed-loop geothermal techniques. With closed-loop geothermal, warmth is extracted by pumping water by a sequence of drilled holes, moderately than by way of fractures within the rock. Whereas the quantity of drilling such a system requires has traditionally made it uneconomical, advances in drilling productiveness enabled by issues comparable to PDC bits may doubtlessly change this calculus.
First, it’s tough to foretell the trajectory of know-how, and what some functionality will finally be used for. Again and again, we see know-how spillovers, the place know-how developed in a single trade for some specific objective finally ends up spreading to different industries, typically to resolve very totally different issues.
Oil and gasoline drilling know-how repurposed to create geothermal energy techniques is after all one instance, however there are a lot of others. Steadily advancing microchip know-how made it doable to generate the downhole telemetry that made horizontal drilling possible, and tremendously lowered the price of processing giant 3D seismic datasets. PDC drill bits, which tremendously elevated oil and gasoline nicely drilling productiveness, had been (sarcastically) initially developed by the DOE for geothermal nicely drilling. 3D seismic mapping, which proved crucial to Devon Power’s horizontal drilling efforts, was primarily based on know-how initially developed to seek out Soviet submarines. Early demand for directional drilling within the US got here from offshore oil and gasoline platforms, in addition to the Atomic Power Fee, which wanted to drill directional wells to collect samples from underground nuclear assessments.
Fracking additionally reveals the significance of serendipity, and of a eager eye for uncommon patterns in scientific and technological discovery. Fracking was initially developed when Floyd Farris occurred to note the connection between acid injection stress and subsequent nicely efficiency. Mitchell’s breakthrough got here when a fracking gel didn’t set correctly, and Nick Steinsberger started investigating the nicely’s subsequent efficiency. Such serendipitous developments are widespread, from the creation of titanium dental implants to the invention of fast-drying automotive paint.
Mitchell additionally benefited from authorities oil and gasoline funding efforts such because the Eastern Gas Shales Program, begun in 1976 by the DOE’s predecessor ERDA, which was half of a bigger authorities effort to develop different sources of pure gasoline following the Seventies vitality disaster. Mitchell’s record-breaking frack in 1978 was funded by the Fuel Shales program, and Mitchell’s first 35 shale gas wells had been drilled with authorities funds. Mitchell (together with different gasoline shale producers) additionally extensively studied the maps and different knowledge produced by the gasoline shales program when attempting to “crack” the Barnett. Authorities assist was additionally crucial for the event of different oil and gasoline know-how, comparable to 3D seismic mapping, microseismic fracture mapping, and PDC drill bits.
However, know-how improvement stays dangerous and unsure. There have been many instances, in accordance with Mitchell geologist Dan Steward, that improvement efforts within the Barnett had been “on the verge of failing.”
This underscores one last lesson: know-how improvement and commercialization typically requires an especially very long time, a long time or extra. Mitchell Power spent 17 years and over $250 million {dollars} drilling wells into the Barnett Shale, gathering knowledge and experimenting with totally different fracking strategies, earlier than it developed a technique that labored and commenced to show a revenue. It took years of studying and experimentation earlier than Mitchell cracked the code, and related studying and experimentation could be required when adapting Mitchell’s strategies to different shale gasoline sources. Mitchell’s success in flip was constructed upon a long time of earlier advances in fracking know-how, 3D seismic measurement, downhole monitoring know-how, improved drill bits, and so forth.
As oil and gasoline drilling know-how will get repurposed and additional developed as a geothermal vitality know-how, will probably be helpful to maintain these classes in thoughts.
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