using transient temperature analysis to evaluate...

Using Transient Temperature Analysis to Evaluate Steam Circulation in SAGD Start-

up Process

Lijuan (Judy) Zhu, M.A.Sc., Fanhua (Bill) Zeng, Ph.D., P.Eng.,

Gang (Garry) Zhao, Ph.D., P.Eng., Farshid Torabi, Ph.D., P.Eng.

University of Regina

Outline

Introduction (background, TTA)

Methodology (assumptions , models)

Two-system, three-system and superposition

Results and discussion

Sensitivity analysis

Synthetic case studies

Field case study

Conclusions

Recommendations2

Introduction

Steam ChamberInjected steam expands vertically and horizontally in the formation.

ImportanceHeating effectiveness estimation;SAGD optimization (evenly distributed);Communication determination in start-up.

Steam chamber may not be evenly distributed

3

Technologies Available

4

3D/4D (time-lapse) seismicPros: Direct, successful applications;Cons: 1) Expensive, only shot at long time-interval;

2) Methane or Steam? 3) Resolution; 4) 2-D view;

3D/4D (time-lapse) seismicPros: Direct, successful applications;Cons: 1) Expensive, only shot at long time-interval;

2) Methane or Steam? 3) Resolution; 4) 2-D view;

Temperature analysis

Temperature analysis

ThermocouplePros: Stand high temperature, permanentCons: Several points

ThermocouplePros: Stand high temperature, permanentCons: Several points

Fiber opticPros: Continuous monitoring Cons: 1) Hydrogen ingression; 2) Elevated temperature? New Optolog@DTS-HT (Kaura, 2008), hydrogen resilient

Fiber opticPros: Continuous monitoring Cons: 1) Hydrogen ingression; 2) Elevated temperature? New Optolog@DTS-HT (Kaura, 2008), hydrogen resilient

Other approaches

Application of Temperature Analysis

Non-thermal recovery process:

1) Infer sand-surface flow rate of each layer;

2) Complement Transient Pressure Analysis (TPA) : φ, K and thermal properties (Duru & Horne, 2010);

Thermal recovery process:

Duong(2008) proposed a model to use exponential integral solution for radial heating to estimate cooling time and formation thermal diffusivity for a SAGD process.

5

No longer new

TTA Technology for SAGD Process

180

200

220

240

1 10 100 1000 10000

Log cooling time, days

Tem

per

atu

re, C

temp@50,3,25

temp@50,4,25

temp@50,1,25

TTA

TTA

TTA

Transient Temperature Analysis

Objective: T->shape/sizeTo evaluate steam chamber size and shape distribution along the horizontal wellbore using temperature falloff data obtained from fiber optics or thermocouple after injector is shut-in.

Approach: Shape/size->TTo establish P.D.E. to calculate temperature falloff based on the temperature distribution when injector is shut-in.

6

MethodologyAssumptions Heat conduction is dominant in shut-in period; Homogeneous and infinite-acting(conduction) reservoir; A radial coordinate system.

Models developed1.Two-systems 2.Three-systems 3.Superposition-in-space

7

2

2

1 p

t

CT T T

r r r K t

ρ∂ ∂ ∂+ =∂ ∂ ∂

Ts Ts

TrSystem1

System2

R

Rw

∞

Tr

Ts

Tr

Ts Ts

TrSyste

m1mSyste

m2

R1R1

R2

R

w

∞

System

3

Ts

Tr

Tr

Ts Ts

TrSystem1

System2

R1

R2

Rw

∞

System3

T

s

Tr

Ts Tr

TTA vs. TPA

( , 0)( , ) r t iP r t P= = ( ) Ω∈== rforTtrT s0,

( ) Ω∉== rforTtrT r0,

Solution to TPA is not applicable to TTA! Other app roach.Solution to TPA is not applicable to TTA! Other app roach.

2

2

1 tCP P P

r r r K t

φµ∂ ∂ ∂+ =∂ ∂ ∂

2

2

1 p

t

CT T T

r r r K t

ρ∂ ∂ ∂+ =∂ ∂ ∂

8

Sensitivity Analysis—Hot Zone Size/Shape in Two-system Model

D

D

td

dT

ln

The shape of the hot-zone determines the shape of temperature and its derivative curve.

The larger the hot-zone is, the later the temperature starts to falloff.

Ts Ts

TrSystem1

System2

R

Rw

∞

Tr

Ts

9

The chamber size and shape plays a significant role.The chamber size and shape plays a significant role.

1. The existence of transition zone slows down the temperature falloff. 2. The larger the transition zone is, the greater the temperature falls off.

Sensitivity analysis –Transition Zone in Three-system Model

Tr

Ts Ts

TrSyste

m1mSystem

2

R1R1

R2

R

w

∞

System3

Ts

Ts Ts

TrSystem1

System2

R1

R2

Rw

Ts

Tr

TsTr

The effect of transition zone can’t be neglected.The effect of transition zone can’t be neglected.

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Synthetic Case (SAGD Start-up)BASIC SIMULATION PARAMETERS

Rock Fluid Property

Permeability 6.12 Darcy

Porosity 0.337

Pi 2000 Kpa

Soi 0.799

Swi 0.201

Ti 8 C

µo 80 poise

Thermal property

Matrix Thermal conductivity 2.74e5 J /m-day-C

Heat capacity 2.347e6 J/m3-C

Oil Thermal conductivity 1.15e4 J /m-day-C


Water Thermal conductivity 5.35e4 J /m-day-C


Well constraints

Q 50 m3/day

Steam quality 0.6

Tinj 250 C

Pinj 4500 Kpa

Ppro 4550 Kpa

Yuan(2010), SPE 143655

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Temperature at Heel

R1=1.15mR2=11.05mD=1m

0

0.1

0.2

0.3

0.4

0.01 0.1 1 10

TD

t(Day)

0

0.2

0.4

0.6

0.8

1

0.01 0.1 1 10 100

TD

t(Day)

TD_CMG

TD_3Sys

TD'_CMG

TD'_3Sys

ln( )D

D

dT

d t

TTA

TTA Interpreted results

Simulation temperature distribution

R1-Radius of the steam zone R2- Radius of the transition zone D- Distance between center and the observing point

T

r

T

s

T

s TrSyste

m1mSyste

m2

R1R1

R2

R

w

∞

Syste

m3

T

s

Tr

T

r

T

s

T

s Tr

R1

R2∞

TsTr

T

sTr

d

12

Temperature in the MiddleR1=1.15mR2=11.05mD=1m

0

0.1

0.2

0.3

0.4

0.01 0.1 1 10

TD

t(Day)

0

0.2

0.4

0.6

0.8

1

0.01 0.1 1 10 100

TD

t(Day)

TD_CMG

TD_3Sys

TD'_CMG

TD'_3Sys

ln( )D

D

dT

d t

TTA

TTA


Interpreted results


T

r

T

s

T

s TrSyste

m1mSyste

m2

R1R1

R2

R

w

∞

Syste

m3

T

s

Tr

T

r

T

s

T

s Tr

R1

R2∞

TsTr

T

sTr

d

13

Temperature at ToeR1=0.7mR2=9mD=0.75m

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.01 0.1 1 10 100

TD

t(Day)

TD_CMG

TD_3Sys

TD'_CMG

TD'_3Sys

TTA

TTA

0

0.1

0.2

0.3

0.4

0.5

0.01 0.1 1 10

TD

t(Day)

TD_CMG

TD_3SysTTA


Interpreted results

T

r

T

s

T

s TrSyste

m1mSyste

m2

R1R1

R2

R

w

∞

Syste

m3

T

s

Tr

T

r

T

s

T

s Tr

R1

R2∞

TsTr

T

sTr

d


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Field Case StudyDuong (2008), SPE 117435

Location of Producer is

consistent with field observation

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

1 10 100 1000

Result of TTA method using superposition of 2-system model

Data obtained on the producer wellbore

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Conclusions

Two-systems, three-systems and superposition radial model have

been established to model the temperature falloff behaviour. The

superposition model can be employed to model complex hot-zone

shape.

Sensitivity analysis indicated the steam chamber size and shape

have great impacts on the temperature falloff.

Synthetic case study suggested the three-system and superposition

model is helpful in evaluating the performance of SAGD start-up

process.

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Recommendations

To establish an advanced model which considers the

contribution of steam condensation.

To develop optimization algorithm for inverse problem

solving, which is to analyze steam chamber size and shape

through interpreting the measured temperature data.

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Acknowledgements

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A. DUONG

using transient temperature analysis to evaluate...

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