RESERVOIR CHARACTERISATION
Injection gas tracer use to
determine communication pathways
to high gas oil ratio producers
The Project
Sampling and Analysis
An oil field operator was experiencing a high gas oil ratio
Tracer was detected in a number of production wells.
in two producing wells that was unexpected. The source
The field map in figure one together with directional arrows
of gas may have originated from one of two injection
shows communication pathways between injection and
wells that were in operation as part of an extensive gas
production wells.
flood campaign. One of the wells was across a fault
l2
block that was thought to be sealing and the other
was some distance away. Understanding the source
of communication would allow the customer to better
balance injection gas and maximise its effect throughout
P1
the targeted sweep zones.
Project Design
Tracerco selected unique gaseous chemical tracers
P2
for each injection well out of their wide range of proven
gas chemical tracer portfolio. Using reservoir and fluid
flow data a project plan was developed. As there was
uncertainty with respect to cross block communication as
well as matrix flow between the injectors and producing
wells a sampling strategy was designed with the
P3
expectation that rapid breakthrough could occur.
Application
P4
Tracerco mobilised to the field and injected a small amount
(less than five kilos) of each of the unique tracers into
injection wells I1 and I2 over one day with no disruption
l1
to normal operations. After injection, customer staff
sampled production wells on a regular basis for a seven
month time period.
Figure 1
RESERVOIR CHARACTERISATION
1.2
Concentration of |1 Tracer ppb v|v
1
0.8
0.6
0.4
0.2
0
P4
0
50
100
150
200
P2
P1
-0.2
Days After Injection
Figure 2
The tracer response curve from injector 1 in wells P1, P2
The lack of tracer from well I2 proved that there was no
and P4 is shown in figure two. There was no response in
communication across the fault block. The lack of tracer
any producers from the tracer injected into I2.
in well P3 highlighted the likely conduction of injected gas
along the fault running North South in the field resulting in
Interpretation of Results
Results showed communication pathways between
injector well I1 and P4, P2 and P1 in that order. There
little sweep of the targeted reservoir and the high gas to oil
ratios in wells P1 and P2.
was no tracer from well I1 detected in well P3. Relative
tracer responses showed that 66% of the injection gas
was producing at well P4 with 21% at P2 and 13% at P1.
If you would like to find out more about this technology please contact a Tracerco Technical Advisor at one of our global
Billingham, UK Tel: +44 (0) 1642 375500
Abu Dhabi, UAE Tel +971 (0) 2 5541672
Pasadena, USA Tel: +1 281 291 7769
Norway Tel +47 55 36 55 40
Kuala Lumpur, Malaysia Tel +603 7803 4622
Rio de Janeiro, Brazil Tel +55 21 3535 7600
www.tracerco.com/reservoir-characterisation. For all email enquiries please contact: [email protected]
Tracerco Limited is a subsidiary of Johnson Matthey Public Limited Company, 5th Floor, 25 Farringdon Street, London EC4A 4AB.
Registered in England No. 4496566. Tracerco is a trading name of Tracerco Limited. TRACERCO and the Johnson Mathey logo are trademarks of the Johnson Matthey group of companies.
XM1012/0/0
operational bases.