What are Unconventional Unconventional Resources...
Transcript of What are Unconventional Unconventional Resources...
Unconventional ResourcesWhat are Unconventional Resources?
Shale Gas/ Shale oilTight Gas SandsOil ShaleCoalbed MethaneMethane Hydrates (Not Producible…..Yet)
Differences: Unconventional Shale Gas and Conventional Plays
Approach to prospectingi.e. Not looking for “clean” unitsDepositional Environments
Deposition of unitsDriving factors of production
i.e. not porosityTOC is the driving geologic factor
US Unconventional Gas Projections
Holditch and Ayers 2009
Unconventional Resources:USA
http://www.mapwv.gov/website/unconventionalresources/index.htm
MarcellusShale
Barnett Shale
Bakken Shale(oil)
Global Shale Gas
Global Unconventional Gas
Holditch and Ayers, 2009
How Does Shale Produce
Low porosity (6%)Very low permHigh TOCBrittle rockNatural fractures
Economic Problems: Unconventional Resources
Cost of Drilling ($4 million for Marcellus wells)Pipe and casing costCompletionEnvironmental RestrictionsEstimation of Reserves
Estimation of Reserves
Jenkins 2009We don’t know how wells will evolve
Depositional Environments: Black Shale
Sub-Oxic Environment
Oxic Environment
Anoxic Environment
-Aerobic bacteria useoxygen to break downorganic matter
-Oxygen is virtually exhausted-Dyserobic bacteria use nitratesas an oxidant-Process is slower
- No oxygen present-Anerobic bacteria use sulfatesas an oxidant-Process is very slow
Need a low amount of sediment input, low circulation and a high amount of organic input in order for a stratiphied water column to develop
Black Shale Modern Analogs: Black Sea
http://blacksea-education.ru/images/map.jpg
Paleo Structure ???
West Limb of the Rome Trough
Onondaga LimestoneOnondaga Limestone Shale Marker
SW NE
Local highsand lows
Black shale is deposited across the study area
Shale appears to be sourced primarily from the NE
Thicker Marcellus deposits exist in Onondaga lows and to the NE
Organic matter extends across the study area, however more organic matter
accumulates in the paleo-topographic lows
Shelf break at A and B
Paleo Structure ???
Marcellus Shale
Anoxic Conditions
Oxic Conditions
Local highsand lows
West Limb of the Rome Trough
OM OM OMOM OM OM OM OM
Onondaga Limestone
Onondaga Limestone Shale Marker
NESW
BA
Depositional Model:Marcellus Shale
West Limb of the Rome Trough
Onondaga Limestone
Onondaga Limestone Shale Marker
Purcell Limestone
Oxic Conditions
Anoxic Conditions Mahantango Siliciclastics
Mahantango Limestone Bed
Mahantango Black Shale Bed
NESW
Tully Limestone
? ?? ?Erosion
OM OM
Harrell Shale
Harrell Shale
Paleo Structure ???
Lower Marcellus Shale
Upper Marcellus Shale
Marcellus Shale
Local highsand lows
Subsidence
? Non-Deposition?
West Limb of the Rome Trough
Onondaga Limestone
Onondaga Limestone Shale Marker
Purcell Limestone
OM OM OM OMOxic Conditions
Anoxic Conditions
Mahantango Siliciclastics
Mahantango Limestone Bed
Mahantango Black Shale Bed
NESW
Tully Limestone?
?
? ?Erosion
OM OM
Harrell Shale
Harrell Shale
Paleo Structure ???
Lower Marcellus Shale
Upper Marcellus ShaleMarcellus Shale
Subsidence
Local highsand lows
Subsidence continues
Anoxia allows for Harrell Shale deposition
The thickest deposits are in paleo-lows
B
A
Depositional Model:Harrell Shale
Data Resources:Unconventional Plays
LithostratigraphyPetrophysical Data
Spectral Gamma LogsXRD and SEMPermeabilityWater Saturation
GeoChemTOC data is essential
Thermal maturity3D Seismic
For optimal well design to avoif structural complexity
Surface to Sub-Surface
Marcellus Shale
Thickness Maps: Marcellus Shale
BA
Spectral Gamma Ray SuiteTh/U ratio is linked to TOC
Spectral Gamma Ray Analysis
Th/U RatioOxidizing
IlliteIllite--PinkPinkSmectiteSmectite--GreenGreen
Th/K RatioTh/K Ratio
Spectral Gamma Ray
XRD and TOC
Establishes if rock can be fracturedEstablishes TOC or Reservoir potential
Regional MappingOrganic RichMarcellus at 15ppm
CI = 5ft
15 ppm
Summary on Marcellus:High TOC 5-15%Very brittle (i.e. fracable)Relatively shallowWide extent Possible 4,359 trillion cubic feet of gas (Engelder 2001)Overall economics can make one Marcellus well more profitable than three shallow wells???????Price of gas is a big issue
Bakken Shale- Williston Basin• ~3.6 billion barrels of oil (recoverable)• Porosity 5%• Perm 0.05 milli Darcy• Recovery Factor 1-5%
Coal Bed MethaneCoal is the most abundant fossil fuelProduce Methane adsorbed to coal surfacesCoal stores 6 times more gas than a conventional reservoir by volumeGas content is 100-800 SCf/ton of coalEconomic production from 0.5 ft-thick coal is possible
Water/Gas production history
Coal Bed Methane Extraction
Drill wellPump water out to decrease pressureProduce desorbed gas
Water Production170K bbls/day
1 Million bbls/day
Coal-Bed-Methane Produced Waters
Tar Sands
Athabaska Tar Sands(or oil sands)Reserves: 1.7 trillion
barrels (assuming 10% recovery)
Venezuelan Oil Sands:
500 billion barrels
Tar Sands- Strip Mining
Tar Sand Extraction methodOpen Pit MiningCrushMix with hot waterBitumen floats (60% bitumen, 30%water, 10% solids)1200 SCF of gas needed to process 1 bbl of bitumen (about 5x energy gain)Upgrading: remove water, sand, impurities, sulfur, catalytic hydrocracking, hydrogenation
Bitumen Separation Cell, Alberta
Suncor Energy Inc.
Canadian Tar Sand Production Canadian Oil Data
Total Production 2,600,000 Barrels/DayExports to US 2,500,000 Barrels/DayToday, about half is from the Oil Sands#1 foreign supplier for USA
Oil ShaleKerogen-rich immature shaleHeating the shale releases oil by pyrolisis
Green River Shale- USA
Green River Shale Resource
1.2 to 1.8 trillion barrels in placeRecoverable?
Global Resource: 2.8 to 3.3 trillion barrels
Oil Shale Production Method
Mining and crushingRetortingOil UpgradingRefining
Disposal and reclamation
Economics
Viable at $70 to $95/bbl in USA
Energy Produced/Energy Used = 3 to 4
Environmental impact is significantWater usage is a problem
Stuart Oil Shale Facility,Queensland, Australia
In-Situ conversion (unproven)
Electric heaters in holes2-3 years heating to 650-700 degrees C
Methane Hydrates(Clathrates)
Crystal Structures
1 mole methane for 5.75 moles water1 liter hydrate= 168 liters methane at STP
Stability
www.nrcan.gov
Gas Seeps on the Seafloor Gas Hydrate Occurrence
ResourceTwice the amount found in all fossil fuelsHow can we produce it?