Integrated Solutions to outperform and deliver historical results on a high drift Well in India.

1. Integrated Solutions to outperform and deliver historical results on a high drift Well in India. India Drilling & Exploration Conference (IDEC) 2017 Changing landscape of oil business May 25-26, 2017, Presenter: Pratyush Tewari (Drilling Engineering Manager, Schlumberger-India)

2. Agenda • Project Background • Drilling Challenges • Applied Methodology • Outcomes • Way Forward

3. Project Background • A renowned Oil & Gas operator in India, has a major hold in a particular field for the last few years • The area has been explored and appraised with different type of well designs • In a new campaign, operator decided to drill a re-entry well in order to achieve new targets • The well design was the most difficult well drilled in that area in terms of drilling challenges and its executable solutions

4. Challenges • A high drift S-type well was planned to achieve the targets with following challenges • Exit the whipstock through Intermediate Casing • Drill the well in planned no. of trips • Drill close to offset wells in tight Anti-Collision scenario • A deep S shape well to achieve, with tight driller’s targets • Tight ECD window in a high drift well • Hole cleaning in 12.25in with major portion at 87deg inclination for 1400m interval • Drill with “LCM mixed active mud system” • Drilling optimization in 8.5in section due to use of smaller sized drill pipes Well trajectory Bird’s Eye View N/S E/W TVD Vertical Section View Departure

5. Methodology Exit the Whipstock and drill as per plan • SLB-“point the bit” RSS technology was a proposed solution for this complicated well profile • Window was smoothly polished for unrestrictive BHA exit • RSS discretely programmed to follow the trajectory under the influence of external magnetic interference at the exit • RSS facilitates trajectory control while rotation which is highly beneficial for a high drift well • “Point the Bit “ RSS has a capability to deliver uncompromised DLS on a consistent basis • A smoother and stable hole profile was required which can be only achieved by RSS • Adequate bit selection done for RSS in order to provide required DLS with superior drilling durability Planned profile

6. Methodology Drill the well in tight AC scenario Primary plan • Biggest challenge of the well was to drill the trajectory without any close approach • Gyro While Drilling (GWD) was selected due its ability to deliver better bottom hole positioning and reduced surveying uncertainty • With the use of GWD the Anti-collision scenario improved and gave more confidence to drill • No previous GWD application in a horizontal well across Middle east and asia • Few applications of the tool worldwide in horizontal wells • Detailed Risk analysis done for the tool functioning and accuracy before making a final decision • Detailed calibration/measurement procedure for GWD was incorporated and survey results compared with the industry recognized MWD surveys in order to match the accuracy of the tool • GWD also helped in hitting a small driller’s target with relative ease compared to standard MWD surveys

7. Methodology Drill the well in tight AC scenario Secondary plan • Advanced Surveying was kept as a contingency to GWD surveys • Advanced surveys are the high definition surveys used for better bottom hole positioning • Use of High definition geomagnetic model to calculate the local crustal field • Use of MWD and RSS surveys to calculate survey points as low as every 3m • Use of SAG and DMAG correction for further reduction of Uncertainty . • Reduced surveying uncertainty for deep wells which is helpful for tight AC scenario and hitting tight drillers targets. • As with GWD, advanced survey also helped in hitting the small driller’s target • Both GWD and Advanced survey was run in tandem and results verified before using as an official survey

8. Methodology Tight ECD window for a high drift well • With low LOT, ECD was monitored and dealt accordingly • On a high drift well ECD can increase sharply and could affect both hole cleaning and wellbore stability • Implemented smaller tubular design for better ECD control in horizontal section • A tight ECD window compelled us to define specific drilling parameters • Controlled ROP specially in the lateral section • Higher RPM in order to clean the cuttings (>150) • Higher flowrate for faster cutting transport to surface ( >900 GPM) • Extensive circulation every stand down

9. Methodology Hole cleaning challenge for a high drift well • A well with “Build-hold-drop” profile requires proper hole cleaning • Difficult to lift the cuttings especially in horizontal profile led to proper adherence to previously mentioned drilling parameters • Wiper trip programmed and executed with ultra caution • Back reamed the sections with higher RPM to keep cuttings in agitated state • Mud rheology maintained upto the mark for smooth trips WITH ROTATION

10. Methodology Avoid tool plugging with LCM mixed mud system • Methodical tests done and guidelines prepared to avoid tool plugging • LCM used in active mud system in order prevent losses • Used in ample concentration in mud system which has a capacity to choke/block minor openings in Smart tools • Laboratory tests done against internal components in order to see the flow pattern and actual blockage. • Concentration and LCM size altered as per the test results • Tool design upgraded in order to accommodate required LCM • Clean mud pumped every stand down in order to avoid LCM settlement . • Special Drilling instructions designed for rig crew to implement correct prevention measures

11. Methodology Drilling Optimization in 8.5in • In depth drilling analysis done to simulate trouble free drilling • 8.5in, being the last section of S shape profile , were more prone to drilling problems like buckling , weight transfer, vibration etc • ECD control led to smaller OD pipes compare to a conventional section which further means TnD problems • Integrated drilling analysis done to understand the BHA vibrations and specific drilling instruction designed to curtail them Sample Plots

12. Outcomes Well profile • Delivered the Directional profile as per plan • SLB- Point the technology helped in achieving bull’s eye on a 3D profile which would have been very difficult with a motor Planar View Plan Actual Well Vertical Section View TVD > 3Km Departure > 2Km

13. Outcomes GWD Success • First Successful GYRO WHILE DRILLING application in Middle East Asia in horizontal section • GWD helped in safely steer away from the offset wells with excellent bottom hole certainty • GWD brought 64% reduction in wellbore uncertainty • The survey quality was excellent and it matched very well with the industry recognized MWD surveys Measured depth

14. Outcomes Advanced Survey Success • First Successful Advanced Survey application in India • Advanced Surveys brought 38% reduction in Wellbore Uncertainty • Survey processed every 3m made sure the landing TVD is correct • Surveys matched with Raw MWD surveys very well • Advanced surveys verified that the targets are hit within the desired tolerance Measured depth

15. Outcomes Good hole cleaning & ECD control • ECD and Hole Cleaning kept under control for more than 2km of Drilling • Systematic drilling practices helped to maintain a maximum of 0.4ppg above the mud wt. • ECD always remain way below LOT value • Able to adequately clean the hole keeping friction factor as low as 0.15 • Achieving low friction factor in a high drift well was highly commendable • Planned drilling parameters and practices helped in delivering a dirt free hole FIT/LOT ECD MW + 0.4ppg Mud Density MW Time

16. Way Forward • GYRO WHILE DRILLING-90 and ADVANCED Survey became a benchmark technology for other operators to follow • With the first use in horizontal well, GWD and Advanced Survey proved its value under tight collision scenario • With GWD and Advanced survey, more laterals can be drilled in thin reservoirs • Industry can either choose GWD or Advanced Survey depending on cost effectiveness • Client-SLB integration has open wide horizon for similar wells in future • Use of fit-for-purpose technology helps to deliver the well as planned • Adequate drilling practices accomplishes the unattainable. • With good drilling practices, ECD and hole cleaning were kept way below the threshold which means there is always a room for further performance improvement. • LCM mud system has opened a new design to encounter wellbore problems • LCM mud system has helped a lot in closing micro fractures and reduce losses • The endurance of LWD / RSS tools in this mud system, proved robustness of current smart tools in the industry • Smart planning and instructions helped in minimizing the tool damage

17. Thank You