1. Mary Pickford

2. Geomechanics Insight Into Drilling of Deviated Wells Through Challenging Soft-hard Formations A Case Study from Godavari Onland, KG Basin
Presenter: Rahul Talreja
Geomechanics Engineer, Schlumberger
Co-Authors:
Koka Raj Kumar, Oil and Natural Gas Ltd
Rajeev Ranjan Kumar, Amol Nakhle, Pratyush Tewari, Schlumberger

3. Introduction
Primary Objective-Matsyapuri (Godavari clay petroleum system of KG Basin)
Logistics, positional and Geographical complications, directional wells were drilled from a land site.
Investigates three lost in hole incidents and other drilling related NPT

4. Well Profiles and Drilling Events
1st Stuck
2nd Stuck
3rd Stuck
Well-B with stuck pipe incidents led to 3 LIH and multiple sidetracks

5. Drilling History Evaluation in Well-B
They have maximum deviations of 60 and 48 and were drilled at azimuths of~150 and 108, respectively. In both the wells, severe wellbore instability issues were encountered in the Godavari clay and the Matsyapuri sandstone formation. Well A suffered approximately 16 days of non-productive time (NPT) whereas well B had 100 days of NPT .  Please check with details mentioned below; it seems well B had 3 LIH so it should hv higher NPT

6. Importance of Geomechanics
Factors determining wellbore stability
Pore pressure
Mud Weight and casing policy*
Stress magnitudes
Stress Anisotropy direction
Rock Mechanical Properties
Wellbore trajectory*
*Factor under human control s1 s2 s3
Stress regime: Thrust
Tensile Failure Shear Failure

7. Offset Well Post-Drill Mechanical Earth Model for 12.25” Section
Held up while lowering Logging Tool
Over-gauged hole condition in shales corresponds to decrease in Rock Strength (UCS values)

8. Offset Well Post-Drill Mechanical Earth Model for 8.5” Section
Differential Stuck while making connections due to overbalance in Sands (~0.3SG); Mud Weight was reduced from 1.3SG to 1.26SG
Good Hole condition as indicated by the caliper corresponds to increase in Rock Strength (higher UCS values)

9. Collapse Pressure Variation with Deviation

10. Well-A: 1st Stuck Pipe Event in 12.25” Section
ECD
Block Position
Hook Load
Standpipe Pressure
Depth
Stuck Pipe
DRILLING PARAMETERS, GPM-750, RPM-60-80,
MUD PARAMETERS
M.WT-1.10/40
PTK Plot
Reciprocation…

11. Mud Weight used while drilling ~1.18SG-1.22SG
Well-A: 2nd Stuck Pipe Event in 12.25” Section
Deviation~60deg
Mud Weight used while drilling ~1.18SG-1.22SG
Mud Type changed to SOBM,
GPM-850, RPM
Mud Weight to 1.22
Matsyapuri Sandstone
SOBM, GPM-850, RPM and Mud Weight 1.22/80

12. Well-A: 2nd Stuck Pipe Event in 12.25” Section
Matsyapuri Sandstone
(a)-Drilling Parameters
SOBM, GPM-850, RPM and Mud Weight 1.22/80
(b)-Stuck pipe mechanism identification
(c)-Basic Logs

13. Well-A: 3rd Stuck Pipe Event in 8.5” Section
(a)-Drilling Parameters
GPM-680
RPM 120
1..24/80
(b)-Stuck pipe mechanism identification
(c)-Basic Logs

14. Hazards identification in the well planning phase
Lessons Learnt
Hazards identification in the well planning phase
Optimum selection of mud weight and casing policy for drilling
Drilling parameters in deviated wells (GPM and RPM)
BHA Centralization
Learnings Applied in Future Wells

15. Geomechanics is part of Engineering Planning.
Without it, we are often like FIREMEN,
Dealing with problems after the event of failure.

16. Thank You