Production Geology Approach as a tool to accelerate
the implementation of advanced drilling technologies:Intelligent Well Evaluation Methodology
Ana Maria Hernandez
IADC World Drilling conference, Madrid, June, 2002
Production Geology Approach
Knowledge Gaps:
Time&
Money
Knowledge Management
Geology
Production
AdvancedDrilling
& Completion
Technologies
Intelligent Well Evaluation Methodology
Technological Background
Initial screening criteria: production geology scenarios
Intelligent Well Systems: Geological Constraints Down hole Sensors Isolated Control flow Zones Surface Systems
Intelligent well technologies and new trends in Economics
Production Geology Approach: Case Study Multilateral technology
Why Intelligent Wells?Measurement - Control - Monitoring
Applications: To monitor gas \ water
coning problems in oil rims
To measure, control and monitor injection & production fluids in complex reservoirs
Reservoir drainage improvement
Remote control and monitoring in hostile environments
To avoid well interventions
>>>>>
Isolate Control Zones
Down hole
Sensors
Surface
SystemsTelemetry
Well
Where to apply Intelligent well technology?
Initial screening criteria: reservoir candidates
Oil rims in heterogeneous reservoirs
IOR projects in complex reservoirs
Improvement of drainage strategies in reservoirs with technology maturity
Offshore projects with economic potential
Areas under environmental regulations
Intelligent Well technology vs. Reservoir types
Critical zones: partially connected sands in the middle part of the reservoir
ME-J1U/L
ME-S2,3
ME-M2
ME-T4,5<
ME-L
ME-M1
ME-S1
ME-JIU
ME-CME-J1U
ME-C
ME-S1
Type 1:Structural/faulted reservoirs with high
lateral & vertical heterogeneity Type 2: Heterogeneous reservoir associated
with salt domes
Type 3: Stratigraphic traps with
internal compartmentalization
Type 4: Bypassed oil zones in
stratigraphic reservoirs
Reservoir scale
Oil rims and complex IOR in mature heterogeneous reservoirs
GOC
WOC
Irregular
GOC
&
WOC
Water
coning
Water / Gas
Coning
Gas
Coning
Bypassed
Oil
Lower reservoir
Change in petrophysical
properties
Change in reservoir
architecture
Upper reservoir
Critical Zone: partially connected sands in the
middle part of the reservoir
More control and monitoring is needed to avoid production problems
Critical zone
Km
m
Borehole seismic::
Range ~ 2-100 m
High resolution
Geometry limitation
4C/4D seismic:•3D geometry•Reservoir coverage•Limited resolution
Resistivity sensors:•Range 0-10 m•Permanent monitoring
Data Gap vs. Technology
Source: The leading edge (april, may 1999)
Borehole seismic systems
More borehole seismic configurations are needed to
improve well to well visualization
Project EconomicsFlow Cash, NPV
ValvesChokesControl ZonesSensors
Identification of variables that produce economical impact
Variable 1
Variable 2
Variable n
Search of the probability distribution to model each variable
Determination of variables with high impact
Sensitivity analysis of each variable
Run the Simulation
Analysis of results
How to determine the impact of geological variables at inter-well scale? Decision support tool for technology assessment
NPV
1141.17
45
5.6
11.57
100.00
40.5
11.23
6.16
1895.83
16
14.0
8.52
150.00
43.5
9.55
13.84
-200.00 0.00 200.00 400.00 600.00
STOIIP
Wells to drill
Plateau rate
Discount factor
Facility size
Recovery
Well cost
Well rate
Geological variables at inter- well scale
Target Forecast: Reservoir variability
Reservoir continuity (km-m) .44
Vertical connectivity (m) .50
Kv/kh ratio .49
Flow units (m) .75
-1 -0.5 0 0.5 1
Measured by Rank Correlation
Sensitivity Chart
Flow unit is the geological variable
with more impact related with
Intelligent well technology
Reservoir architecture vs.
well architecture
+200 150 100 50 25 15 5 mReservoir Candidates
North Sea
Gulf of Mexico
Indonesia
West Africa
Venezuela
Reservoir flow units dimensions
The design of isolated control zones should take into account
the dimensions of the reservoir flow units to optimize production
and avoid production problems
Sand production proneScale prone
OptimalCompletion
window
200-20 m
Production flow units:
Rock types + rock wetability + rock strength
Drainage pointsHorizontal well
Isolated control zones at perforation scale
Bigger completion windows: high lateral and vertical heterogeneity
but more homogeneous rock types (quartz arenites)
Isolated control zones 200-20 m
Isolated control zones +/- 200 m
A.- Horizontal well
B.- Multi branch well
Isolated control zones: best geological options in
reservoirs with bigger completion windows
PRODUCTION BEHAVIOR HIGH ANGLE vs. CONVENTIONAL WELLS
0
500
1000
1500
2000
2500
3000
0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000
OIL RATE (BOPD)
WE
LL
HE
AD
PR
ES
SU
RE
(P
SI)
FUL-63 FUL-68 FUL-70 FUL-75
FUL-56 FUL-59 FUL-61 FUL-651/2"
1"
3/4"
1 1/2"
1 1/4"
C.- High angle wells perforated following the completion windows
Example El Furrial Field - VenezuelaEl Furrial Field - Venezuela
High
Angle
Wells
production
Typical wells
SPE 56430
Proposed Isolated control zones
Isolated control zones: North Sea Case
SensitiveScale
intervals
Sensitive Sand Production intervals
Scale proneCompletion
window Sand production prone
20-5 m
Horizontal well
• Red intervals will produce sand/scale since the beginning if they are perforated• If yellow intervals are perforated
any change in the flow regime will activate the production problems
Reservoirs with high lateral & vertical heterogeneity
and high internal heterogeneity (rock type: litarenites)
A.- Low/high angle wells
Isolated control zones + 200 m
Proposed Isolated control zones: North Sea Case
B.- Optimal completion windows in small-channel zones:
perforation optimization
Horizontal well
Completion window
How to determine the impact of geological variables at perforation scale?
ProducerSurprise
handling
InjectorWater
Breakout
Decision variables
Assumptions Variability
Uncertainty
Forecast
InjectorInjection pointsValves/chokesZonal flow sensors
ProducerDrainage pointValves/chokes producerPermanent resistivity sensors
Interwell dataDistance between wellsCompleted intervalPerforationrock typesrock wettabilityrock strenghtpore pressurebarrierslayersSurprise handlingWater Breakout
Monte Carlo Simulation
Target Forecast: Surprise handling
rock strength .54
rock types .52
rock wet ability .49
layers .05
internal barriers .01
-1 -0.5 0 0.5 1Measured by Rank Correlation
Sensitivity Chart
Drainage
points
Injection
points
Proposed Rock type Analysis
Reservoir Pressure
BottomHolePressure
Rock type window ?
Oriented rock type perforation
RockType
Rock Strength
Rock type vs. Rock Strength
Rock type window
IW project Brainstorming
Identify Technical Issues related with IW
Identify Economical Issues related with IW
Identify IW PotentialScenarios
Initial Options Screening
IW production Optimization Solutions
Prospective IW economic scenarios
Identify Critical Decision Issues
New trends in petroleum economics
Discounted Cash Flow Analysis
IW Case history selection
IW Reservoir Modeling
Intelligent well projects: screening criteria
- 6
- 4
- 2
0
2
4
6
1 2 3 4 5 6TIME [MONTHS]
CA
SH
F
LO
W [
MM
$]
Production
Initial Investment
Workover Costs
NPV | BASE CASE
CONVENTIONAL WELL MULT ILATERAL WELL
NPV |MLT<
Cash flow analysis
Life cycle cost analysis(2)
Intelligent wells goal is to capture everyday events
in the reservoir. Can we analyze them using
conventional petroleum economics?
Forecasting & risk analysis (1)
Economic threshold: Decision Tree (3)
(1) SPE 37932,63528; (2)SPE 35315;(3)63201
Advanced decision- making technical/economical tools to justify new technology
Technology A
Technology B
Technology C
High Risk0
5
10
15
20
25
30
35
40
scen
a.
1
scen
a.
2
scen
a.
3
var. 1
var. 2
var. 3
Technical/ Economical
ranking matrix
Reservoir Scenario 3Scenario 2
Scenario 1
Variables that impact
economically the reservoir
Multi-objective Decision Analysis (3)
Dynamic Complexity
Dynamic Complexity (1)
Multi-prospects Evaluation (2)
(1) SPE 52954;(2) SPE 69614; (3)SPE 68579
ActivityLevel
MutualHelp
Coalescence
IndividualEffort
Potential• Multidisciplinary
Team• Compilation of Information
Information Analysis• Business Plan • Reservoir Review • Technology Maturity• Opportunity identification
Unification ofEfforts
Maturity3 Technical Forum
• Drilling/completion• Geomechanics• Case Studies• Potential proposals
Results
Actions
Dispersion
Year 2000
Domestic development• Technical Proposals• Operational know-how
TechnologyKnowledge
How to accelerate the implementation of advance drilling technologies?
Knowledge management. Example MTL Technology; PDVSA, Venezuela
Production Geology Approach
Production Geology “ THE FRAME”Combination of:• Structural Styles• Reservoir Types• Rock types• Flow Units
•.... a techno-economic challenge
Technology- a solutionThe key: Right Technology in the right frame using
the optimal oil recovery process
Acceleration of technology implementation
Reduction of cost/ increase of value
Multidisciplinary approach: identification of best practices
Uncertainties reduction, production optimisation
MTLFailure
MTLsuccess
MTL Failure
MTLsuccess
Multi laterals 1995-1998
Multi laterals 2000 +
1998MTL technology
Abandoned
1999MTL
Corporative Effort
Evolution of the Multilateral Technology in Venezuela; PDVSA, Venezuela
5 Wells
20 Wells