dr. adrian f. park geological background to shale-gas in new brunswick

Dr. Adrian F. Park

Geological background toShale-gas in New Brunswick

Outline

1. Conventional & unconventional petroleum

2. Fracking

3. Shale gas potential in NB4. Outstanding issues

CLASTIC SEDIMENTS

Classified by composition and grain-size

Environments of deposition(Sediments sorted by grain-size and energy of water flow)

Deltas - Lake Ayikum, TibetSand and gravel in river channels

Fine sand and silt on delta front

Mud plumes

Environments of deposition (organics)

Delta-top swamp/forest (peat)

Off-shore algal blooms & detritus(sapropelic mud)

Organic detritus(sapropelic mud)

Mississippi delta, Gulf of Mexico

4. Traps

gas

oil

trap

Permeable layer with water (aquifer)(oil and gas float)

Impermeable layer (aquitard)

Conventional Oil and Gas

Unconventional Oil and Gas - directly exploiting the ‘source rocks’(the trick is extracting the hydrocarbon content)

OIL SHALE - the first petroleum industry

Scotland 1780s to 1860s

The ‘bings’ of West Lothian c. 2000

Albert Mines, NB1840s to 1880s

North America’s first petroleum industry

Images courtesyNB Museum and NB Archives

AND A LITTLE CLOSER TO HOME

Abraham Gesner1797 - 1864

US EIA

Frederick Brook, NB

Horton Bluff, NS

RESERVEv.

RESOURCE

Estimated reserveProven reserve

Recoverable reserve

1 GJ ≈ 0.5 bbl oil ≈ 28m3 gas

Marysvillesubbasin

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??

Courtesy Steven Hinds, NB DNR, 2013

With unconventional oil and gas the problem isgetting the oil and gas out

In 19th century thisinvolved mining andmajor environmentaldegradation

21st century thisinvolves ‘fracking’

‘Fracking’ (also ‘fraccing’) - enhancing permeability by fracturing

Images courtesy of NB DNR

Oil workers ‘fracking’ an oil well with nitroglycerine, 1903, NB

Natural pressure gradient with depth(between 2.6 and 3.0 tons/metre2

for each metre down)

Between 250 and 300 m depth fractures arenaturally sealed by lithostatic load

Drinking water aquifers usually lie above this zone

Deep aquifers where water pressure = loadusually salty and non-potable

Fractures created in one rock layer generally donot spread into other layers because ofdifferent mechanical properties between rocktypes (even within rock types)

Corridor hydrofracturing tight sandstone reservoirat McCully, Sussex since c. 2003

‘Hydraulic fracturing’ or ‘hydrofracking’(first used 1948, last two decades more widespreadalongside horizontal drilling)

Causes for concern (shale-gas):

1.Leakage of gas (or oil) in drinking water aquifers through induced fractures

2.Leakage of wells into aquifers

3.Hydrofracturing liquids and possible toxic effects

4.Hydrofracturing noise and air quality

5.Surface leakage and contamination (waste water disposal)

6.Hydrogen sulfide, heavy metals, radioactive materials

7.Earthquakes induced by hydrofracturing and deep well injection disposal

Hydrofracturing operationsWaste waterSeismicity

‘Hydraulic fracturing’ or ‘hydrofracking’

Hydrofractured shale

Freshwater aquifers

2 + km

CANDOR – this is a hydrofrac operation

Well-pad

Pumps & compressorsSlickwater

storage

Producingwell-pad

Fracking additives from the Apache/Corridor Elgin project

Sodium hydroxide used in manufacturing soap (lye, caustic soda)Carboxymethyl cellulose ingredient in laxatives and toothpasteBentonite clay - used in water filtersXanthan gum polymer food additive and food processingSodium bicarbonate component of baking powderBarite medical uses as an X-ray blocker (barium meals)Base oils (e.g. HT 40) synthetic oil and mineral oilCalcium chloride food preservative, de-icing fluids, electrolyte drinksPolyamide/fatty acid blend

(Novamul) comparable to linseed oilCalcium hydroxide ‘lime’ – whitewash and fertilizerGlutaraldehyde biocide, surgical & dental disinfectant

Manufactured by Petrocan under Federal license(proprietory)

FULL DISCLOSURE

Some concern as carcinogenUsed to prevent formation of H2S

Waste waterRecovered hydrofracturing liquids

Production water

Drilling fluidsHydrogen sulfide, radionuclides, heavy metals

have not been an issue thus far.Waste water is a strong brine (2 – 3X seawater)

Treatment and disposal:Until 2012 – waste water treatment and disposal at Debert, NSCurrently transported by road to Levis, Quebec

Deep-well injection currently not an option

Alternatives to slick water hydrofracturingLiquid propane, nitrogen foam, carbon dioxideRemove hydrofracturing water from consideration

Microseismic monitoringduring hydrofracturing

Required in North Dakota,and BC(used at Elgin)

Microseismic activity during a hydrofracturing process, Barnet Shale, Texas

18 July – 18 August 2015

Seismicity in Canada

UK draft regulations consider

‘acceptable levels’ of seismic activity

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