Terrifying! Injected oilfield wastewater may trigger earthquakes for ‘decades.’ More terrifying: Percentage of high-magnitude quakes felt at the surface increases with depth of waste injected & may create greater magnitude quakes years after injection rates decline or stop.

Think about the quake consequences of hydraulic fracturing and steam injection (SAGD) and the consequences of the massive volumes of mystery chemicals injected that remain underground and “migrate.”

Oilfield wastewater may trigger earthquakes for ‘decades’ by Patrick Galey, July 16, 209, phys.org

Wastewater from oil and gas production injected deep into wells could cause earthquakes strong enough to be felt on the surface for years to come, according to new research published Tuesday.

The United States is undergoing a boom in oil and gas production as well as fracking, the process of shooting water mixed with sand and chemicals deep into the earth to bring up hydrocarbons trapped inside rock.

Wastewater from fossil fuel production has long been associated with tremors, as producers dispose of it by injecting jets into separate wells dug below ground.

The United States Geological Survey says that wastewater disposal from oil and gas production is the number one cause of human-induced earthquakes in the central and eastern US.

A team of experts from Virginia Polytechnic and State University now believe that the wastewater, due to its higher density, can pose an earthquake risk for years to come, since it displaces existing groundwater stocks that keep the ground stable.

They developed a model based on the wastewater flows in two fracking-heavy states, Kansas and Oklahoma.

The team found that the wastewater altered the subterranean fluid pressure to such an extent that it posed a quake risk for decades.

“That has some very interesting and I think important consequences for how we understand the hazard posed by oilfield wastewater disposal,” said Ryan Pollyea, lead author of the study, published in Nature Communications. [What about the hazards posed by frac’ing?]

Tremors of magnitude 3 or greater used to be relatively rare in the central United States.

But in the wake of vast fossil fuel exploration, their numbers have skyrocketed from around 20 a year in 2008 to more than 400 annually.

One particularly strong quake struck Oklahoma in September 2016, measuring 5.6 magnitude—large enough to be felt in seven states, from Texas to Iowa.

A peer-reviewed study a few months later suggested that four of the most five powerful Los Angeles Basin quakes of the early 20th-century oil boom may have been caused by oil and gas production.

Pollyea and the team found that the earthquakes were also getting stronger: in the two states analysed the number of magnitude 4 quakes increased 150 percent since 2016, while the number of 2.5-magnitude tremors went down by over a third.

They are also getting deeper.

“We have found a new mechanism to explain how fluid pressure causes and increases earthquakes deep under ground,” Pollyea said.

“Our study can be used to improve hazard models for injection-induced earthquakes by accounting for fluid pressure variations that occur after injection operations are reduced or stopped,” he told AFP.

Stronger earthquakes can be induced by wastewater injected deep underground by Science Daily, July 16, 2019


Virginia Tech scientists have found that in regions where oilfield wastewater disposal is widespread — and where injected water has a higher density than deep naturally occurring fluids — earthquakes are getting deeper at the same rate as the wastewater sinks.

Perhaps more critically, the research team of geoscientists found that the percentage of high-magnitude earthquakes increases with depth, and may create — although fewer in number — greater magnitude earthquakes years after injection rates decline or stop altogether.

The study, led by Ryan M. Pollyea in the Virginia Tech College of Science’s Department of Geosciences, was published July 16 in Nature Communications. It shows that in areas such as Oklahoma and southern Kansas there is evidence that oilfield wastewater injected underground into the Arbuckle formation has a much higher density than natural fluids occurring within the deeper seismogenic zone faults.

The problem: The wastewater sinks and increases fluid pressure deep underground when it has a higher density than fluids already there naturally. Pressure changes so deep — at depths up to 5 miles or greater — can cause more high-magnitude earthquakes even though the overall number of earthquakes is decreasing.

“Earthquakes are now common in the central United States where the number of magnitude-3 or greater earthquakes increased from about 19 per year before 2008 to more than 400 per year since,” said Pollyea, an assistant professor of geosciences and director of the Computational Geofluids Laboratory at Virginia Tech. (Pollyea adds that the overall earthquake rate per year has been declining since 2016.)

“In many cases, these earthquakes occur when oilfield wastewater is disposed of by pumping it into deep geologic formations,” Pollyea added. “As wastewater is injected deep underground, fluid pressure builds up and migrates away from injection wells. This destabilizes faults and causes ‘injection-induced’ earthquakes, such as the damaging 5.8-magnitude earthquake that struck Pawnee, Oklahoma, in 2016.”

“This was a surprising result,” Chapman said. “It suggests that sinking wastewater increases fluid pressure at greater depths and may cause larger earthquakes.”

By analyzing earthquake data, the researchers found that the number of earthquakes greater than a magnitude 4 increased more than 150 percent from 2017 to 2018 while the number of earthquakes with magnitude 2.5 or greater decreased 35 percent during the same period.

More bluntly, the overall number of earthquakes is starting to decrease, but the percentage of higher-magnitude earthquakes is increasing.

“Our models show that high-density wastewater may continue sinking and increasing fluid pressure at depths of 5 or more miles for 10 or more years after injections stop,” Pollyea said. “There is a larger proportion of high-magnitude earthquakes at depths greater than 5 miles in north-central Oklahoma and southern Kansas, but there are fewer total earthquakes at these depths. This implies that the rate of high-magnitude earthquakes is decreasing more slowly than the overall earthquake rate.”

The study also found that fluid pressure caused by sinking wastewater remains in the environment much longer than previously considered.

“Our models show that high-density wastewater continues sinking and increasing fluid pressure for 10 to 15 years after injections stop, and this may prolong the earthquake hazard in regions like Oklahoma and Kansas,” Pollyea said.

It’s important to note that Pollyea and his colleagues are not saying that all oilfield wastewater disposal operations cause earthquakes, nor are they predicting a large and potentially damaging earthquake in the Midwest region. Nor does the study indicate that density-driven pressure build-up occurs everywhere that oilfield wastewater operations occur.

Researchers have known since the 1960s that pumping fluids deep underground can trigger earthquakes, Pollyea said, but this study is the first to show that the density of the wastewater itself plays a role in earthquake occurrence. The heavier the fluid, the greater the effect of displacement of natural fluids and the greater the fluid pressure change. To wit: Take a cup of salty ocean water heavy with dissolved particulates and dump it into a glass of regular tap water. Before the two eventually mix, the heavier ocean water will sink to the bottom, displacing the “lighter” tap water upward.

“Past pore-pressure models have assumed the density of injected fluids are the same as that in host rocks, but the real world begs to differ, and injected fluids are often heavier,” said Shemin Ge, a professor and chair of the Department of Geological Sciences at the University of Colorado, who was not involved with the study. “This study looks into the effect of heavier fluids on pore pressure and consequently on inducing earthquakes. Heavier injected fluids have the tendency to migrate downward, which, interestingly, tracks the occurrence of earthquakes.”

Funding for this study came from the United States Geological Survey, Earthquake Hazards Program.


Story Source:

Materials provided by Virginia TechNote: Content may be edited for style and length.


Journal Reference:

  1. Ryan M. Pollyea, Martin C. Chapman, Richard S. Jayne & Hao Wu. High density oilfield wastewater disposal causes deeper, stronger, and more persistent earthquakesNature Communications, 2019 DOI: 10.1038/s41467-019-11029-8

Refer also to:

“Newly revealed” steam injection disaster, this one by Chevron in California. About 800,000 gallons (~3 million liters) oil & water seeped into stream bed, off and on since May. CNRL seemed unable to stop their steam injection caused seep in Alberta, will Chevron be able to stop this one?

Cushing, Oklahoma: 4.5M earthquake ignores newly imposed frac quake prevention rules

“Devastating Domino Effect?” 5.0M Earthquake Causes “Substantial Damages” to 40-50 Buildings in Downtown Cushing, Rattles Residents Across State; Felt as far away as Johnson City, TN, 1297 km away

Oklahoma’s boasted frac quake mitigation failing, badly! More homes damaged by two 4.2M quakes Sunday NE of Enid; Court coddling oil companies causing quakes, leaving people plaintiffs dangling

New Study: Oklahoma’s induced seismicity strongly linked to wastewater injection depth

Oklahoma seismologist, Austin Holland, scolded by fracked academia (the dean!) for linking earthquake swarms to powerful oil and gas industry [Can’t dare let oil and gas bribery money, aka donations, get in the way of science or the truth!]

5.6M (originally reported as 5.8) Pawnee Oklahoma Earthquake Officially Largest In State History with Many “Felt” Aftershocks; USGS might upgrade it to 5.7M

Pawnee Oklahoma’s 5.8M earthquake caused river to rise. Not just waste injection causing earthquakes in Oklahoma, frac’ing causing them too, like in BC & Alberta

Hydraulic fracturing volume is associated with induced earthquake productivity in Duvernay play, Fox Creek Alberta

Do fracking activities cause earthquakes? Seismologists and state of Oklahoma say yes, Earthquakes increasing in volume and intensity around fracking and waste disposal sites

CAPP Induced Planned Deflection & Dismissal of Frack Quake Risks & Harms? U of A Study: Human-induced seismicity (leaves out the tens of thousands of small frack quakes) and large-scale (why leave out the medium & small-scale production that’s fracked?) hydrocarbon production in PA, WV, OK, ND, TX, USA and SK, AB, BC, Canada

5.1 M: Oklahoma frac waste quakes rumbling bigger & bigger as USGS predicted. Children scurry under school desks, “and it was great,” say administrators

Frac Hell in Oklahoma: Endless quakes. “There’s no lack of conversation. There’s a lack of action.” Plumber blamed for gas leak in elementary school

More Frac Quakes Rumble ‘n Rock Oklahoma: The Big Warning Causes Sleepless Night for Thousands. When will the shaking stop? When will the “regulator” regulate?

Updated because the frac quakes go on & on & on: Oklahoma again orders oil & gas drillers to reduce amount of frac waste water injected. Why? The natural gas leak & home explosion in Oklahoma City? Where will the frac waste go?

Frac Hit at Fox Creek? Wanna bet industry’s pet lamb, AER, will issue no fine? 460,000 litres fluids & contaminated water spews forth from abandoned Sproket Energy Corp well 6 km SW of Fox Creek, Nothing reported in the media!

3.9M earthquake west of Frac’d Crazy Fox Creek Alberta reported by Earthquakes Canada, 1 km depth

Frack Patch Porn: The ultimate sexual assault by men in positions of power? Ensign drills Canada’s longest lateral, 7,770 metres (4.828 miles), at global frac-quake capital, Fox Creek, Alberta. Is it the world’s longest lateral onshore?

“Insane” Greed: Fox Creek Shakes as Frackers Drill for Condensate to Dilute Bitumen

UPDATED WITH MORE QUAKES, Fox Creek, Alberta Frac Quakes start up again; New Study by Standford Scientists: Small earthquakes at frac sites may be early indicators of bigger quakes to come; Surprising Finding: Arkansas earthquakes mostly caused by hydraulic fracturing, only some by wastewater injection, None caused by trucks

Why isn’t AER’s Fox Creek Frac Frenzy Regulatory Failure front page news? AER releases evaluation of its Play-Based (Blanket Approval) DeRegulation Pilot

AER allows Repsol to resume fracking after causing world record 4.8M frac quake (felt 280 km away near Edmonton) in AER’s Fox Creek Blanket Approval Frac Frenzy Free-for-All Experiment. But, Repsol appears too shaken to resume

Canada breaking frac quake records

630CHED Jespersen Show Interviews Jessica Ernst on her Supreme Court of Canada Hearing vs AER & Dr. Jeffrey Gu on the 4.8M Earthquake at Fox Creek, Alberta (day of Ernst’s Supreme Court Hearing)

Fox Creek: Yet another earthquake in AER’s deregulated blanket approval frac experiment. Fracking-Related Earthquakes Could Ding Credit Quality

Do we need another “independent” frac study? The AER asks: How far do we go? Fox Creek residents react to the latest 4.4 Magnitude quake

Chevron reported 3.6 magnitude event; Shut down by AER. Is the AER’s Frac Quake Stop Light System Irrelevant? Another 4.4 Magnitude Earthquake at Fox Creek

Did Alberta Just Break a Fracking Earthquake World Record with 4.4 Temblor at Fox Creek? Sounds of Silence: The Crooked Lake Earthquakes

Fox Creek frac quakes make AER play deregulation with you and your loved ones: “Red Light = Green Light”

Fracking Quakes Pose Added Risks but Oil and Gas Companies Refuse to Share their Collected Seismic Data. “In low seismic environments like Fox Creek where the natural earthquakes are infrequent, the hazards from an induced seismic event can exceed the hazards from a natural source”

Fox Creek Mayor Jim Ahn rightfully worried about frac quakes harming sour gas infrastructure in the community. How much damage have the quakes already caused sour gas wellbores and pipelines?

Frac Hit at Fox Creek? 460,000 litres fluids & contaminated water spews forth from abandoned Sproket Energy Corp well 6 km SW of Fox Creek

This entry was posted in Global Frac News. Bookmark the permalink.