Know your reservoir.

Recover more.

Hydrocarbon tracer technology for well analysis

Jon Spencer – Reservoir Technical Supervisor - Americas

What tracers can tell you about your reservoir

Know your Reservoir

From Interwell Tracers in a Traditional Oil Field

To Inflow Tracer Technologies in Unconventional Wells

2

What Can Be Measured?

An old engineer’s adage that is still valid today.

Unless you measure something you don't know what it isdoing or what effect it is having.

– What can we measure?

• Interwell Water Flow Dynamics

• Interwell Residual Oil

• Horizontal / Multi-lateral Flow

• Long-term Inflow of Hydrocarbons

• Stimulation Results on Oil & Gas Production

3

What data is achievable?

What data is achievable?

What data is achievable?

What data is achievable?

What data is achievable?

What data is achievable?

What data is achievable?

What data is achievable?

What data is achievable?

12

13

As this case history indicates, there is not a direct relation

between frac fluid clean up and hydrocarbon production.

Complementary Technologies

13

Tracer data confirms effectiveness of stimulation program

Understand the

geophysical, stimulation,

and

production data

Data is another Tool in the toolbox

14

• No formation issues

• Tracer does not partition

between phases

• Low detection limits

• Minimizes environmental

consequences

• Cost effective

15

Know your Reservoir

Why Use Tracers?

“Tracers provide the only direct means of tracking

[Water/Gas/Oil] movement in a reservoir thus, allowing the

determination of the reservoir flow dynamics

What is an effective tracer?

• Are non-reactive and

stable within the reservoir

Know your Reservoir

From Injectors

To Producers

Interwell tracers map how your field is connected.

Prove where barriers to flow & fault lines exist

Prove if cross flow is happening through faults and vertical zones

16

Measuring the amount of tracer recovered we can quantify:

Swept Pore Volume

Sweep Efficiency

and provide meta data for simulators …

Not just for one well, but for all the wells in the field.

Know your Reservoir

Not only see the flow dynamics and breakthrough times, but

17

Gas migration pathways and volumes were quantified to establish communication and sweep areas.

18

Know your Reservoir

Such as identifying flow behaviours prior to full field planning and project scale up

At the pilot stage of new flood projects

To evaluate specific injector to producer flow connections

Breakthrough allows the source of high water cut or gas/oil ratio to be determined

EOR StudiesWhen evaluating various recovery mechanisms & different conformance treatments (e.g. viscosified polymer floods)

When to use Interwell Tracers

19

Residual Oil Saturation Measurement

Using Interwell Partitioning Tracers

20

Residual Oil Measurement

- Uses partitioning and non-partitioning tracers

- Both tracers added to injection well together

- During transit between wells, passive tracer moves only with the water

- Partitioning tracer

interacts with

residual oil and

lags the passive

tracer for finite

time periods

21

Partitioning Tracer Benefits

- Non-intrusive and low cost test

- Provides measurement of oil

saturation in the region

between

injectors and producers as

opposed to surrounding a

wellbore

- Test can be run during

normal operation

- No loss in production

22

Partitioning Tracers

Oil saturation (So) is related to the time lag in between the two tracers:

23

Oil Saturation Using Tang Method

Time delay of the

partitioning tracer can

be re-written as:

This implies that if we divide tp by 1+, the curves will

overlap. 1+ can be calculated and used to estimate So

24

Oil Saturation Using Tang Method

0

500

1000

1500

2000

2500

3000

3500

4000

4500

0 30 60

C(t

) p

pt

Days Post Injection

Passive

Partitioning

0

500

1000

1500

2000

2500

3000

3500

4000

4500

0 30 60

C(t

) p

pt

Actual Tracer Arrival Time

Passive

Partitioning

25

Case Study

I1

I1

W4

W3

W2

W1

Sweep efficiency was confirmed using

tracers to ensure that there is relatively

good sweep and that the breakthrough

times are reasonable

A non-partitioning tracer was injected,

along with a partitioning tracer with the

known k value of 0.39, at the same time

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Case study - Results

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0.00 10.00 20.00 30.00 40.00 50.00 60.00

No

rmal

ised

con

cen

trat

ion

plo

t C

(t)

Days after injection

Well 1

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0.00 10.00 20.00 30.00 40.00 50.00 60.00

No

rmal

ised

co

nce

ntr

atio

n p

lot

C(t

)

Days after injection

Well 2

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0.00 10.00 20.00 30.00 40.00 50.00 60.00

No

rmal

ised

co

nce

ntr

atio

n p

lot

C(t

)

Days after injection

Well 3

Well 1 Saturation calculations

beta 0.261433447

So 40.13%

Well 2 Saturation calculations

beta 0.22119389

So 36.29%

Well 3 Saturation calculations

beta 0.524351388

So 57.35%

Beta 0.247

So 38.77%

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Adding it all up: