Cross discipline use of the Modular
Formation Dynamics Tester (MDT) in
the North Sea
John Costaschuk, Dann Halverson, Andrew Robertson
Res. Eng.
Petrophysicist
Geologist
Content
• Defining the Value of Information and the Functionality of the Modular
Formation Dynamics Tester (MDT)
• Examples of value creation within BP’s North Sea operations:
A. Operational Value
B. Subsurface Value
InSitu Fluid
IFA & Asphaltene EoS
Analysis
Vertical Interference Test
(IFA)
• Summary and Conclusions
C. Project Value
Acquisition of live
microbial samples
Defining the Value of Information
• Many E&P decisions are difficult to make, involving significant
capital expenditure for uncertain gain.
• Value enhancement comes from allowing more robust decisions to
be made, as a result of more reliable forecasting of the uncertain
parameters and outcomes.
− Operational
− Subsurface
− Project
• Value of Information (VoI) compares the value associated with a
decision, informed with and without extra information.
• The reliability of the additional data is crucial to understand.
The Functionality of the Modular
Formation Dynamics Tester (MDT)
Conventional openhole
pressure data is difficult to
interpret in some areas of
the resource:
• Depletion signal impacts
interpretation
• Low matrix perm in parts
of the reservoir
High Pressure Pump
Focused Sampling Probe
Large Diameter Probe
Guard Fluid Analyser for
focused sampling
* (IFA) InSitu Fluid Analyser
Reservoir Formation
InSitu Fluid Analyser
Reservoir Formation
Adding IFA* data increases
reliability of the fluid
interpretation:
• Viscosity
• Optical Density
• Fluid Density
• Resistivity
Sample Chambers
Operational Value of MDT
Operational Value of IFA:
A. Operational Value
•
•
•
•
Rapid determination of fluid contacts
Allows on the fly programme modification
B. Subsurface
C.modification
Project Value
Allows
on the flyValue
well test design
Resultant time cost saving on data acquisition.
Conversely allows you to optimise a programme when
you only have a very limited time window.
Recent appraisal experience:
Insitu Fluid
Analysis
(IFA)
• IFA
The&top
ranked objective
of a well was to confirm OIP
asphaltene
EoS
Acquisition of live
by establishing FWL within the segment
microbial samples
Test that a reliable
•Vertical
It wasInterference
critical to ensure
free water
sample was captured before weather terminated the
operation.
Operational Value of MDT
IFA confirmation that well objective met
• What is the critical time estimate for clean-up, before which quality
samples can be taken? Is the rock of adequate mobility?
• Should the sample point be re-placed along the open-hole environment
and clean-up restarted?
• Under poor weather conditions, when have the objectives been met, and
thus can the run be terminated?
Operational Value of MDT
IFA confirmation that well objective met
Shut-in
Resistivity
Shut-in
Density
Operational Value of MDT
IFA confirmation that well objective met
Well Objective (#1)
•
Confirm OIP by establishing FWL within segment.
IFA Observation
•
FLOWING: Resistivity saturated up to 6900s, but after this resistivity drops in
spikes: non-continuous water phase (droplet) becomes more continuous;
relatively low viscosity bulk phase
•
SHUT-IN: After the pumps are stopped at 10600s two immiscible fluids
appear to segregate in the flowline, and a water density is measured at the
AFA sensor at the bottom of the flowline
IFA Interpretation
•
Mixed flow of two immiscible fluids when sampling
− Free water phase
− Oil phase or mud filtrate
Reliable
Information
8
Subsurface Value of MDT
IFA integration with lab and depletion data
Reliable
Information
Subsurface Value of IFA and asphaltene EoS:
− Alternate matches to the petroleum system model
− Connectivity and compartmentalisation
A. Operational Value
Insitu Fluid
Analysis
(IFA)
B. Subsurface Value
IFA & asphaltene EoS
Vertical Interference Test
C. Project Value
Acquisition of live
microbial samples
IFA Data
Pressure
Data
Subsurface Value of MDT
Vertical Interference Test Data
Subsurface Value of Vertical Interference Test data:
− Uncalibrated petrophysical model
A. Operational Value
Insitu Fluid
Analysis
(IFA)
− DST test / no test decision required
B. Subsurface Value
C. Project Value
− Kh and Kv/Kh uncertainty in missing core interval
IFA & asphaltene EoS
Vertical Interference Test
Acquisition of live
microbial samples
Project Value of MDT
Acquisition of live microbial samples
Project Value in acquisition of live microbial samples
A. Operational Value
Insitu Fluid
Analysis
(IFA)
• Reduce uncertainty on reservoir souring mechanism
and evaluate injection water design options
B. Subsurface Value
C. Project Value
Recent appraisal experience:
• A specialised bottle preparation and sample handling
protocol has been developed between BP, OilPlus and
Schlumberger
 Pressurised water samples are not required for
molecular work
IFA
asphaltene water
EoS samples are required for
 &Pressurised
Acquisition of live
transferring and setting upmicrobial
the culture
samples
Vertical Interference Test
• After three months incubation of the pressurised culture
no significant hydrogen sulphide generation was
observed (multiple bottles for each penetration).
Summary and Conclusions
• Operational Value of InSitu Fluid Analyser (IFA):
− When and where to sample relative to well objectives
• Subsurface Value of IFA & asphaltene Equation of State:
− Alternate matches to the petroleum system model
− Connectivity and compartmentalisation
• Subsurface Value of Vertical Interference Test data:
− DST test / no test decision
− Kh and Kv/Kh in missing core interval
• Project Value of acquisition of live microbial samples
Questions
• Thank you for your attention and interest.
Credit:
Paul Roylance & Gavin Fleming (Operations Geologists)
Ilaria de Santo & Jonathan Haslanger (Schlumberger)
Keith Robinson & Richard Jonson (Oil Plus)