A detailed project on anti-collision monitoring in Oil& Gas Industry

1. Anti-Collision Monitoring
By
Shreyansh Shukla (B80026778)
Kukadiya Naitik (B80026745)
Kaustubh Sudhakar (B80026741)
Under the Guidance of
Prof. Sanjay Joshi

2. Nomenclature
• Anti-Collision = AC
• Close Approach = CA
• Ellipse Of Uncertainty = EOU
• Separation Factor = SF
• Traveling Cylinder = TC
• Subject Well: The well of primary interest e.g. the well plan
• Object Well: All offset wells and other well plans
• Calculation Interval: the depth interval (MD/TVD) at which calculations are
performed

3. Objectives
• Introduce the various methods of determining
well bore clearances from neighboring wells.
• Highlight the pros/cons of the different methods
• Explain the effects of EOU on anti-collision
• Explain anti-collision policies.
• Present the AC analysis process
• Present interpretation of AC reports
• Explain the use of the Traveling Cylinder diagram

4. Introduction
• Anti-collision?
• Why is it necessary?

5. Separation Factor
• Ratio of Ct-Ct separation to EOU-EOU
separation
– 1.0 = Ellipses touch each other
– >1.0 = Separation between EOU’s
– <1.0 = EOU’s overlap

6. Ellipse Of Uncertainty
• Always Use 3-D Confidence Level
• Set desired confidence
• Major Radii
• Oriented EOU – risk based
• Mixed model types

7. COMPASS
• Problems causing deviation in well trajectory
- Rock properties…
What COMPASS does?
• Directional Well Path Planning
• Survey Management Planning
• Anti-Collision

8. Analysis Methods
• Horizontal Plane
• Normal Plane
• 3-D Least Distance
• Closest Approach
3-DLeastDistance
N o r m a l P la n e
H o r iz o n t a l P la n e
S u b je c t (p r o p o s e d )
W e ll O b je c t (o ffs e t)
W e ll
C lo s e s t A p p r o a c h

9. Horizontal Plane
• Simplest of methods
• Looks at horizontal displacements at common
TVD’s
• Associated with the use of “Spider Plots”
• Usually done using TVD step interval, but can
also use MD
• Calculation scan is down subject well….but
really doesn’t matter

10. Horizontal Plane (cont)
• PowerPlan also includes inflection points on
wells exceeding 90° inclination
• Limited use..only for very specific applications
– Waterflood effects
– Relative formation penetrations (flat lithology)
• Has limited use in horizontal wells…use MD
• Produces very distorted TC diagrams

11. Normal Plane
• Method defining a TC diagram – disk sliding
down the subject well…always normal to
wellbore direction
• Always us MD calculation interval
• Always looks ahead of current position

12. Normal Plane
• Scan is down the
“object” (offset)
wells…ensures that
entire offset well is
analyzed.
P e r p e n d ic u la r In te r s e c t io n
S u b je c t W e ll O b je c t W e ll
S c a n n in g D o w n
S u b je c t W e ll....
M is s e s P e r p e n d ic u la r
In te r s e c tio n s
N o r m a l t o S u b je c t W e ll

13. Normal Plane (cont)
• “Object” well
scanning provides
more insurance that
perpendicular
approaches are
detected
• Can have multiple
solutions – separate
traces
P e r p e n d ic u la r In t e r s e c t io n
S u b je c t W e ll O b je c t W e ll
S c a n n in g D o w n
O b je c t W e ll
M u ltip le S o lu tio n s
N o r m a l t o S u b je c t W e ll

14. 3-D Least Distance
• Provides least distance to offset well (at point of
analysis)
• Does not consider direction of well…point on
offset well could be behind you (so do you really
care)
• Highly unlikely for solution to lie on normal plane
of subject well… so makes distorted TC diagrams
• Only considers least distance solution when
multiple solutions exist … can make results dis-
continuous

15. Closest Approach
• Closest distance between well segments
(between actual survey stations)
• Not dependent on calculation interval
• Will be normal to “both” wells (except at well
head/TD)

16. Anti-Collision Policy Rules
• Policy Rules
 Policy Purpose
 Policy Application
 Procedure

17. Risk Levels
• Major Risk
– Life, Environment, Property Risk
– No drilling allowed
• Minor Risk
– Shut-in well
• Alert Zone
– Indication of wells to be included

18. Risk Analysis Process
• HARC
• Technical aspect
 Ellipsoid of Uncertainty
 Tool Error Model Selection

19. Report Interpretation

23. 23 DLA
10/15/16

24. 24 DLA
10/15/16

25. Conclusion
25 DLA
10/15/16

26. Questions?
• What was missed?

27. Where to Get More Information
• Resources aklestad-ofspublicreferences sugarland domain
(guest/guest)
– SPE 19989 – The Travelling Cylinder – A Practical Tool for Collision Avoidance
– SPE 22546 - Development of Drilling Close Rules for Dubai Petroleum Co
– SPE 23041 - Site Selection, Well Planning, and Collision-Avoidance Considerations for the Piper Field Redevelopment
– SPE 23941 - Application of Risk Analysis Methods to Subsurface Well Collisions
– SPE 23942 - Supplement to SPE23941, Application of Risk Analysis Methods to Subsurface Well Collisions
– SPE 30692 - New Real-Time Anticollision Alarm Improves Drilling Safety
– SPE 37667 - Case Histories Demonstrate a New Method for Well Avoidance and Relief Well Drilling
– PowerPlan Technical Reference Manual
– BP Amoco – Directional Survey Handbook
• Contacts
• Darren Aklestad – aklestad@slb.com (281) 285-7291
• Chris Chia - cchia@sugar-land.oilfield.slb.com (281) 285-7350