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Hydraulic Fracturing  ‘Fracking’ Prof Richard Davies


Professor Richard Davies Professor of Energy Director Durham Energy Institute Durham University UK richard.davies@dur.ac.uk •

1995‐2003 oil and gas Industry

2003‐Present Academic in UK

Published over 70 papers on petroleum geology ∂

2007‐2011 Lusi mud volcano from drilling (13,000  homes lost). Company claimed earthquake – we  determined well blowout.

Working on hydraulic fracturing risks

Durham University, ranked 3rd in UK


Hydraulic fracturing of low permeability rock

Used to increase the permeability of  rocks that have low permeability  ‘tight’

E.g. low permeability sand or shale

Source BGS


Stages of development Many years Drilling and  Hydraulic Fracturing

∂ Seismic Data

Production

Exploration Well Good

Good

Poor

Poor

Stop

Stop

Abandonment

Geology


Well casing and cementing •

Aquifers and environment protected  by steel casing and cement

The casing and cement for wells   being fractured are the same as  normal oil and gas wells

To check that cementing has been  done well a ‘cement bond log’ is  taken

Mature technology that needs to be  properly carried out


Water use ‐ volumes •

Volume of water used is modest (8,000 – 23,000 m3) 

But flowback water needs to be treated or re‐injected

Companies will have to develop plans to responsibly  dispose of waste water

e.g. Pennsylvania, USA ∂

Source: Susquehanna River  Basin Commission.


Fracking fluids •

99.5% Water and sand

0.5% chemicals to help the fluid generate fractures 


e.g. Barnett shale (Texas) – data from Halliburton • 1000s of hydraulic  fracturing operations  completed

aquifers

• Fractures measured • Spikes on the graph are  fractures that grew  upwards and  downwards 

∂ 2700 m

reservoirs


Can fracking cause water contamination? Davies, R.J., Mathias, S. A., Moss, J., Hustoft, S., and Newport, L., in press Hydraulic  Fractures: How Far Can They Go? Marine and Petroleum Geology.

No fractures taller  than 600 m

350 m

~ 1%

∂ •

No fractures greater than 600 m

In USA leak due to natural processes  and poor cementing of casing


Earthquakes • Energy due to fracking cannot be felt at the surface • One exception is 2.3 M event  in UK  • UK government introducing  new rules in case this  happens again with  operations stopped in 0.5M  felt

Energy due to fracking


Readily detected

•Change in orientation •Increased magnitude

After Maxwell et al (2008)


Readily detected


Lancashire, UK, 2011 • As a result potentially new  legislation hydraulic  fracturing


Seismicity: thousands of fracking operations in USA Barnett Shale USA

After Warpinski et al 2012 and Green et al (2012)

x 30,000  Lancashire, UK (2011) ‐ exceptional

x 1,000 

1.5

2.0

2.5

felt Not felt


Summary

Hydraulic fracturing is not a new technology

Concerns on water contamination, induced seismicity and waste water

These risks need to be fully researched, quantified and placed in context  with other energy technologies


Thank You

Hydraulic fracturing. "Fracking" (англ.)  

Hydraulic fracturing. "Fracking"

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