1. Integration of 3D-shared earth model with Drops Drilling Simulator to reduce drilling costs
NFR project /210
Presented in Stavanger 4 April 2003
Presented by
Runar Nygård, Drops Technology AS
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2. Outline of presentation
Project description
What is drilling optimization?
DDS – Drops Drilling Simulator-Technical description
Results so far
Summary
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3. Project participants Drops Technology AS
Drops Technology AS was founded in It is a limited company incorporated in Oslo, Norway
DROPS Technology AS sells services, program licenses and user access, based on DROPS’ drilling optimization simulator DDS 2.7
PGS-Tigress
PGS-Tigress is 100% subsidiary of PGS
PGS-Tigress is a software company for the Exploration and Production professionals with a suite of integrated tools
The main product being TIGRESS (The Integrated Geoscience and Reservoir Engineering Software System).
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4. Project description
Today the Drops Drilling Simulator needs drilling data as reference to build the physical drillability needed for the simulator to simulate drilling.
This project will extend the drilling simulation capabilities so other data from logs and seismic attributes from a shared 3D earth model can be used as basis for drilling simulations.
Using such information would also give better prediction of drillability variations related to different well paths.
GOALS
Implement DDS in Tigress shared earth model software
Develop new models for drillability based on other type of data than drilling data
Develop automatic well planning routine in Drops Drilling simulator
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5. Tigress
Integrated software for all disciplines in petroleum exploration
PC version is Linux based
Powerful database (PDR)
Open link to other software (data loading)
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6. Drilling optimization: Simulation tools
Today’s oil and gas industry utilize simulators mainly in three of the four main operational engineering disciplines
Reservoir, production and formation evaluation all use simulation tools to better evaluate different scenarios and to improve interpolation and economics
In advance the production, reservoir and seismic/log analysis can be performed
Drilling Engineering has a lack in planning tools available for the actual drilling process
Drilling software is mainly related to the fluid system and well-rock interaction (well integrity)
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7. Drilling optimization: Learning Curve
The Learning Curve has been slow and expensive.
Even after wells have been drilled in the same formations in a field there are still many combinations of bits and operating conditions that have not been tried
Therefore you might not have reached the lowest drilling cost
Utilizing a simulator that can simulate these combinations in a short period of time after the first well has been drilled, is definitely a strong tool
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8. Drilling optimization: Cost equation
Required inputs are actual bit costs, rig rate, and other costs
The simulator calculates rotating time (from ROP), connection time and trip time
The individual bit run cost pr. meter and the cumulative cost pr. meter are used to evaluate the optimum in terms of economics
Other costs, like: MWD/LWD, DD, down hole equipment, fluids, personnel, boats and other
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9. The Drilling Optimization Simulator simple overview
An earlier drilled well well is the reference
The simulator iterate a perfect match from the reference “drillbehind”. Output from this is a strength log, ARSL
This strength log is used as basis for the next well
Adjusted for lithology (formation thickness) and survey, the new well can be optimized
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10. Technical Approach
Predictive ROP models have been developed in the past two decades
ROP models exist for Rollercone, PDC and NDB/Geoset bits
Describe the physical interaction between the bit and the rock as a function of the parameters that effect the bit performance.
Different bits have different cutting mechanisms.
The cutting mechanism is integrated over the entire bit face and converted to ROP in meter/hr.
As the bit penetrates through the different formations the bit wears, which again effect the ROP.
The ROP models use unconfined rock strength as an input
The ROP models can be used to predict unconfined rock strength if ROP is known.
The models have been verified in the laboratory and field
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11. © Drops Technology AS

12. Apparent Rock Strength Log (ARSL) Creation Procedure
Each Bit-/BHA run is treated separately
Simulations are performed for each bit with different ROP models dependent on bit type
“Apparent rock strength” is calculated based on an initially assumed bit wear coefficient
A new wear coefficient is then estimated and a multiple solutions iteration procedure for the entire bit run is performed until the calculated bit wear equals the actual bit wear
The resulting “apparent rock strength” log is now specific for the formations in this area
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13. DROPS Drilling Optimization Simulator
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14. Needed input data for ARSL creation
Drilling, mudlogger and bit data needed
Drilling data - Depth, ROP, WOB, RPM, Flowrate, Plastic Viscosity, Mud Weight
Mudlogger data - Formation thickness Percent lithologies, Pore Pressure
Bit Data- Size, Type, Jets, Number of cutters and blades, Backrake, Siderake, PDC layer thickness, Backup Cutters Info., Depth In, Depth Out, Wear In, Wear Out, TFA and POA.
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15. Drops Drilling Simulator DDS
Currently used in planning, follow up and post analysis of wells
DDS is a Windows based application and the interface is user friendly, just “point and click”
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16. Drops Drilling Simulator DDS
Control sheet window
Cost is re-calculated based on every simulated change
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17. Drops Drilling Simulator: The ARSL
Existing drilling data is used to calculate a ARSL (Apparent Rock Strength Log)
The ARSL is used to plan and simulate the forthcoming wells in the field
Assumption is that the drillability properties for each formation does not change from well to well
The simulator does not take into consideration any 3D-effects like anisotropy in stress field or mechanical data
Up to now there has been time consuming to simulate numerous different well trajectories
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18. Learning Curve for One Bit
Learning Curve for Section Using One Bit.
Bit A
Bit B
Bit C
Bit D.
Bit E
Total Cost for Section, $
900000
800000 10 20 30 40 50 60 70 80 90
100
110
120
130
140
150
160
170
180
190
Number of Simulations.
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19. Learning Curve Multiple Bits
Learning Curve for Section Using Multiple Bits.
Bit C
Bit B
Bit B
Bit A
Bit A
Bit A
Bit A
Bit B
Bit D
Bit B
Bit D
Bit A
Bit C
Bit D
Bit D
Bit C
Bit C
Bit A
Bit C
Bit E
Bit D
Bit B
2 X Bit D
Total Cost for Section, $
900000
800000 20 40 60 80
100
120
140
160
180
200
Number of Simulations.
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20. Simulator results: ROP
Measured and Calculated ROP vs depth 50 45
Measured ROP 40
Calculated ROP 35 30
ROP, m/h . 25 20 15 10 5
3650
3700
3750
3800
3850
3900
3950
4000
Depth,
mTVD
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21. Simulator Results: Rotating Hours
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22. Simulation of Bit wear (Reported Wear 2-6) Bit Wear Evaluation8
Bit Wear Evaluation
Center 7
Gage
Average 6 5
Bit Wear . 4 3 2 1
2854
3000
3050
3100
3150
3200
3250
3300
3350
3400
3450
3500
3550
3600
3650
3688
TVD (m)
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23. Drops Drilling Simulator: Real time Follow up
In addition to being a planning tool, DDS has functionality for comparing the planned well program with the actual data from the rig
Conduct rapidly decisions in unforeseen situations
Re-simulate the planned program with new equipment, bits, etc.
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24. Software integration Task 1
Implement DDS in Tigress shared earth model software
This has been done by running Drops using vm-ware in Linux
All data needed for running DDS is stored in PDS.
Vector based special bit information is implemented in Tigress as an drilling event
Adjusting data for DDS based on new well trajectories is easily done in Tigress by using their G&G modules
DDS 2.7 is now commercially for sale by Tigress
This task of the project is finished as planned
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25. Results: Software integration
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26. Software integration
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27. Software integration
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28. Software integration
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29. ARSL based on other strength criteria
When bit is penetrating the rock, different modes of failure occurs in the rock like, shearing, crushing and tension fracturing
The drillability is the resistance of the rock being penetrated by the drill bits
Drillability of the rock is a dynamic parameter
However, Rock strength and drillability are closely connected
In this ongoing work we have been able to establish rock strength based on different electric logs which is comparable with the ARSL based on drilling data.
One exception is for harder zones which still some additional work remaining
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30. ARSL: From other sources
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31. Variation in properties: Anisotropy
Anisotropy effects
Stress field
Rock strength may have anisotropic behavior
Or large variations
Effect when drilling:
If directional change determine an increase in mudweight this will increase drilling time and increase wear
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32. Task 3 progress report Task 3.
Develop automatic well planning routine in DDS
By developing algorithms that make more of the drilling simulation automatically there is a possibility to increase the numbers of well scenario which is simulated
A new bit routine is underway. This routine will make it possible to automatically simulate different bits for each section and thereby increase the numbers of simulations performed and increase the value of planning
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33. Summary Up to now our project followed its original progress
Task one, the software integration went well
Drops believe that being part of a larger software package to the oil companies will give economical results in near future
We believe that drilling simulation will be common in the future so the time works for us, not against us
We would like to thank NFR for giving a small company as ours the possibility to do research. Whiteout NFR support we would not have been able to do it
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34. Example: Day to day follow up
8 1/2” Section Time-Depth Curve
3500
3600
3700
3800
3900
4000
4100
4200
4300
4400
8.5 in Pilot
8.5in Simulated
8.5in Actual
RPM recommendations not followed
Measured Depth (m)
Rig was informed
that bit will wear out
before TD
Trying to save five
hours resulted in a
loss of 15+ hours
(or about $ ) !
Trip for Bit Change
Bit Quits Drilling 5 10 15 20 25 30 35 40 45 50 55 60
Time (hrs)
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