Shale gas development: US experience - UK application Energy Institute, London
10 December 2014
Roy Hartley CEng FEI Chartered Petroleum Engineer
Consultant Petroleum Engineer
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In preparing this lecture the Author has used data
from the public domain and provided a reference to
the source. If anyone objects to the use of any data
or to the reference please contact the Energy
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Shale Gas Development – US Experience – UK application
• What is Shale Gas / Oil ?
• How is it extracted ?
• US Experience ?
• Regulatory Regime US vs UK ?
• What are the Environmental Impacts ?
• What are the Benefits ?
Plant material, algae organic matter in mud
Depth, pressure, temperature, Millions years mud shale Organic matter oil/gas
Formation of Hydrocarbons
UK has shales of similar age and environment to US
Large grains – porous – high flow capacity
Very small grains – insignificant flow capacity
Carbonate
40%
1. Limited clay constituents- generally less than forty percent, 2. Static Young’s modulus >3.5 * 106 psi, 3. Dynamic to Static Young’s modulus consistent with clastic reservoirs (not shales), 4. Isotropic (no laminations) on the core plug scale, 5. Gas flow at effective confining conditions through an un-propped crack.
Key for fracture stimulation
SPE125525 Larry K. Britt and Jerry Schoeffler,
Actually fine-grained clastics and not shale “shilts or shands.” Use of a clean, non-damaging fissure dilating fluid, like water, has distinct advantages over the use of gelled fluids.
Successful shale plays: • 2% TOC • >40m thick • Depth > 1,000m • Overpressures • Vitrinite reflectance of 3% (measure of thermal maturity) • < 40% Clay minerals • > 100km2 surface area – avoiding towns / AONB etc. • Palaeogeography and structural setting • Legacy Wells to provide data • Shows of gas and oil whilst drilling • Conventional Fields nearby
Shale Gas Life Cycle
Seismic Site Drill & Frac
Produce Re-
Instate
Months 1 1 >4 >84 1
Trucks ~ 4 ~200 ~1,000 ~400 build ~200 ~2 / week
> 2km
< 5km
<1 km
Shale
Constituent (% vol.) Example Purpose
Water and sand 99.5 Sand suspension Sand grains hold microfractures open
Acid 0.123 Hydrochloric acid Dissolves minerals in the rock
Friction reducer 0.088 Polyacrylamide Minimizes friction
Surfactant 0.085 Isopropanol Increases the viscosity of the fracture fluid
Salt 0.06 Potassium chloride Creates a brine carrier fluid
Scale inhibitor 0.043 Ethylene glycol Prevents scale deposits in pipes
pH-adjusting agent 0.011 Sodium, potassium carbonate Maintains effectiveness of additives
Iron control 0.004 Citric acid Prevents precipitation of metal oxides
Corrosion inhibitor 0.002 n,n-dimethyl formamide Prevents pipe corrosion
Biocide 0.001 Glutaraldehyde Minimizes bacteria – corrosive by-products
Breaker 0.01 Ammonium persulphate Delayed breakdown of gel polymer chains
Crosslinker 0.007 Borate salts Maintains fluid viscosity at temperature
Gelling agent 0.056 Guar gum (HEC) Thickens water to suspend the sand
Oxygen scavenger - Ammonium bisulphite Prevents corrosion
Reach - Registration, Evaluation and Authorisation of Chemicals.
Potential Pollution
Frac Zone
Aquifer
Frac Fluids NORM
CO2 CH4 N2O SO2 NOx VOC CO
Based on Altman et al 2011
Evangeline Shrine Club #1 well
GS wells, battery
AM wells, battery
A.L. #1 A.M.#1 wells, battery
FD #1 well
MG #1 well, battery
FD Facility
DF well
ESC #1 well
Barnett Shale
University of Texas at Arlington
Well Paths
Working Rigs and Price Oil & Gas
0
4
8
12
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500
1000
1500
2000
1988 1993 1998 2003 2008 2013
Gas $/Mcf Gas Rig Count Gas $/Mcf
0
50
100
150
0
500
1000
1500
2000
1988 1993 1998 2003 2008 2013
Oii $/b Oil Rig Count Oil $/b
Risk Management
Evolving shale gas management: water resource risks, impacts, and lessons learned†
Brian G. Rahm* and Susan J. Riha
Current scientific understanding of water resource risks in shale gas development, how various stakeholders, have responded to these risks through practice and policy. A structured framework recommended to reduce polarization and to formally engage science in policy- making, together with other economic, social and value considerations.
Pennsylvania DCNR
• 2.2-million-acre state forest system; ~50% available for gas development
• Natural gas development is historical in state forest.
• Significant to economy but, affects recreation, forest’s wild character, scenic beauty, plant, wildlife habitat.
• Overall surface disturbance ~2% of lease tract.
• 2010, hired 15 member monitoring team
• 1,486 acres facilitate gas development; roads, infrastructure, well pads and pipelines.
• Added 33,500 acres to state forest system, 8,900 acres in core gas forest.
• 131 miles road improved for shale-gas development
• 30 miles of new roads
• 191 infrastructure pads constructed to facilitate shale-gas.
• 104 miles of pipeline corridor.
Fracture Growth, Gas/Fluid Migration as Horizontal Fractured
Fracing of 6 wells monitored to determine: 1) max height of fractures 2) if natural gas or fluids from the Shale could migrate
3,800 ft to overlying Upper Devonian/Lower Mississippian gas field
3 shallow producers monitored Production & Pressure histories recorded no increase in the 12-month period after fracturing. 10 months samples = no migration from the underlying fraced Marcellus Shale gas wells.
2,000 ft
5,000 ft
DOE 15 September 2014
Water Stress
Agriculture Oil & Gas
Construction
Food & Beverage
World Resources Institute
Fracked well - two to four million gallons of water to drill and fracture (annual use of 20 to 40 people in the U.S, or three to six Olympic-size swimming pools; the demand is substantially smaller than many other existing industries).
Water Losses
BBC; Offwat
Jackson et al 2014
Methane Emissions
No scientific or technical grounds to ban fracking – but it won’t guarantee
Europe’s energy security, say European Science Academies
EASAC - national science academies of the EU Member States,
EASAC - provides independent expert, evidence‐based advice about the scientific aspects of
European policies to those within the European institutions.
Regulatory Regimes
US • Mineral Owner’s rights over-riding • Controlled by State Mines Dept. • Regulation by Rules / Inspection • Offset in some States 150’ • Road Infrastructure not considered • No involvement of Public
UK • Seeks to involve Public • Controlled by Local Planning Authority. • Seeks to minimise Environmental Impact
– including visual, waste disposal, • Can require roads upgrade • Offset not defined, unlikely to be <300m
“Coalitions” that bring public and industry together are developing in US: Marcellus coalition Muskingum Watershed
Government Guidance
• Minerals planning authorities to develop policies shale gas and coalbed methane.
• Ensure that mineral extraction does not have an adverse impact on the natural or historic environment or human health.
• There is a pressing need to establish – through exploratory drilling - whether or not full scale production is viable.
Planning practice guidance for onshore oil and gas
© NERC All rights reserved
15,000 miles of seismic data
Seismic
GIIP Range 822 – 1,329 – 2,821 Tcf Economically Recoverable? Extracting 10% would supply UK for 25 years. UK consumes about 3 Tcf of gas a year
Bowland Shale
Weald Basin
Shale oil in place 2.20, 4.40, 8.57 bbl
GIIP 49.4 80.3 134.6 tcf, OIIP 3.2 6.0 11.2 bill.b,
Midland Valley – Shale Potential
0.0
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10.0
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1990 2000 2010 2020 2030
Tcf
Alaska Coalbed methane offshore onshore Tight gas Shale Gas
US Gas Production
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Tax component
Price (excl tax)
IEA Industrial Gas Prices 2013
DECC Website
FRED HOYLEOnce a photograph of the Earth, taken from outside, is available, we shall, in an emotional sense, acquire an additional dimension... Once let the sheer isolation of the Earth become plain to every man, whatever his nationality or creed, and a new idea as powerful as any in history will be let loose. (1948) Well, we now have such a photograph... Has any new idea been let loose? It certainly has. You will have noticed how suddenly everybody has become seriously concerned to protect the natural environment... It seems to me more than a coincidence that this awareness should have happened at exactly the moment man took his first step into space.
Earthrise Apollo 8 December 24, 1968
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