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 Gaseous hydrocarbon products withdrawn as an effluent gas.Result: Hydrogen; 45 gravity condensate; 1000 BTU methane gas, and water.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