modeling in situ extraction of heavy oil deposits
TRANSCRIPT
Modeling In Situ Extraction of Heavy Oil Deposits Terry A. Ring & Mikhail SkliarUniversity of Utah
Current MethodsCompany Heating MethodShell Electric HeaterPhoenix WY MicrowaveIEP Fuel Cell Down HolePetro Probe Hot AirChevron Hot CO2EGL SteamExxon ElectrofracRaytheon RF and Supercritical CO2Global Resources Corp. MicrowaveJames Q. Maguire Fracturing (liquid N2 fracturing technology)Mountain West Energy Hot gas
ShellElectric heaters gradually heat shale beneath surfaceTarget depth zone typically from 1,000 to 2,000 feetRock formation heated slowly over time to 650 to 750° FHeat changes kerogen in oil shale into oil and gasContainment by Freeze wallProducts are pumped to surface using traditional methodsProduces approximately 1/3 gas and 2/3 light oilProduces high quality transportation fuels
Other Patterns from Shell
Phoenix Wyoming- Microwave
Microwave methodNote- Phoenix, IEP, and Petro Probe have partnered as Oil Shale Alliance. Inc.
Independent Energy Partners- Fuel Cell Down Hole
Petro Probe -Hot Air
Pressurized air is introduced to an above-ground combustor, superheated and directed underground into the oil shale.Radiant heat in the inlet conduit produces a non-burning thermal energy front of predictable radius in the oil shale surrounding the hole. Gaseous hydrocarbon products withdrawn as an effluent gas.Result: Hydrogen; 45 gravity condensate; 1000 BTU methane gas, and water.
Chevron - Hot CO2
EGL – Steam Injection
Closed loop steam heatingTraditional pumping
Exxon Mobil - ElectroFracMethod heats oil shale in situ by hydraulically fracturing the oil shale and filling the fracture with an electrically conductive material, forming a heating element.Preferred geometry is longitudinal vertical fractures created from horizontal wells with conducting electricity from the heel to the toe of each heating well. Planar heaters such as these should require fewer wells than wellbore heaters and offer a reduced surface footprint.
Electro-Petroleum Inc.EEOP involves passing direct current electricity between cathodes (negative electrodes) in producing wells and anodes (positive electrodes) either at the surface or at depth in other wells.The passage of the current through the reservoir heats the formation via Joule heating, reducing oil viscosity. Electro-osmosis can enhance the pressure gradient toward the well bore, creating an additional drive mechanism.
Raytheon - RF and Supercritical CO2
Thermophysical DataFound
Variable TypeThermal Conductivity GraphHeat Capacity EquationPermittivity GraphStrength & Elastic Properties GraphPermeability Graph
Still need to find:Specific conductanceMagnetic permeability as f(ω)Wave propagation constantThermal Expansion Coefficient
Modeling Approach - IHeating
Conduction and Convection of Hot FluidRadiation may occur
Joule HeatingRF HeatingMicrowave Heating
FlowD’arcy’s Law
Deposit has very small initial porosityLow permeability
Kerogen/Bitumen viscosity is f(T) viscosity is high
Stress AnalysisThermal Expansion of RockPressure Gradient
Gas formation Reaction and D’arcy FlowPushing Fluids
Failure Analysis Cracking
Modeling Approach - II
Pyroloysis of KerogenReaction Kinetics
Liquid ProductsFlow via D’arcy’s Law
Viscosity as f(T)Viscosity is lower
Gaseous ProductsCreate Pressure to Drive D’arcy FlowFlow via D’arcy’s Law
Viscosity is very low
Kerogen Bitumen Oil+gasCarbonate Oxide+CO2Hydrate Oxide+H2O
Heat Conduction
Energy Balance
Radiation Source
ε’, α’ - Kramers-Konig transformation of IR data
Source/Sink Term - Reaction
QTuCTktTC PP =∇+∇−•∇+∂∂ ρρ )(
TT ∇− 3')''( σαε
)(THr rxna∇−
-60
-50
-40
-30
-20
-10
0
10
20
30
40
50
60
500 700 900 1100 1300 1500
Wavenumber (cm^-1)
Rea
l Par
t of R
efra
ctiv
e In
dex
-60
-50
-40
-30
-20
-10
0
10
20
30
40
50
60
500 700 900 1100 1300 1500
Wavenumber (cm^-1)
Imag
inar
y Pa
rt o
f Ref
ract
ive
Inde
x
RF and Microwave Heating
Maxwell’s Equations
Wave Equation Wave Propagation Constant
Heat Source
02
22 =
∂∂
−∂∂
−∇tE
tEE εμσμ
02
22 =
∂∂
−∂∂
−∇tH
tHH εμσμ
02
22 =
∂∂
−∂∂
−∇tu
tuu εμσμ
μσωμεω ik −= 22
k = Refractive Index
)Re()cos( )( kztix AezktAE −=−= ωω
2'' EQ orεωε=
Joule Heating
Je = external current sourceQj = internal current sourcesσ = conductivity = α (T-To)n
Heat Source Term Q= σ (∆V)2
je dQJV =−∇∇− )(σ
Stress Analysis
Strain Tensor, εStress Tensor, σElasticity Matrix, DThermal Stress
)],,([1
),,( zyxTTYzyx avec −−
Φ=Σ<Σ
υα
εσ D=
Mass Balance
U is velocity vectorRj = rate of jth reactionDib = Diffusion coefficient for i in matrix
∑=∇•∇+∇•−∂∂
jjiibi
i RCDCUt
C )(
Model ResultsConduction HeatingFlow
Viscosity = f(T)
Pressure
Temperature profile, velocity vectors and pressure field after 110 days of heating at a well temperature of 1,273°K
3D Model
ConductionFlow
2D Slice Model
ConductionFlowMass
Model Limitation
3D too large for Multiphysics2D too large with complex reaction setsNew Approach
2D model - MultiphysicsAssume reactions go to Equilibrium
Project Status
Initial Proposal for $95KInitial Funding $20 K
Subcontract in Deo/Eddings “Shale Pyrolysis” GrantDid not feel we had enough money to fund MS Student
Started UndergraduateWorked Last SummerTook Industrial work in Fall
Budget Leftover ~$16K