INNOVATIVE CASING DRILLING TECHNOLOGY IMPROVED THE ABILITY TO SET THE CASING DEEPER THROUGH PROBLEMATIC ZONE IN INDONESIA GEOTHERMAL OPERATION Schlumberger Bonar, Drilling Product Engineer Hanafi M. Falhum, Casing Drilling Engineer Pertamina Geothermal Energy Budi Setiawan, Senior Drilling Engineer
Outline 1. Overview, Problem Definition, Challenges & Objectives 2. Casing Drilling Technology as a Solution 3. Engineering & Operation Overview in Well-A 4. Actual Result & Impact to the Operation 5. Summary 6. Q & A Slide 1 of 10
Overview K geothermal field 55 MW potential Well-A one of exploration well in K field, target depth of 3000 m MD 17.5 Section pilot hole partial loss, TD @ 852 m MD Several stuck incidents while POOH Casing unable to go down Stuck pipe and jarring events on the clean out Assembly Exposed for too long decided to sidetrack the hole 17.5 Sidetrack hole same problem, TD @ 952 m MD Several stuck incidents with clean out assembly Could not go down further, stopped at 867 mmd Slide 2 of 10
Problem Definition Formation instability Inability to set the 13.375 casing to bottom No full rotational capability with Casing/liner tieback running tool Challenge & Objective Set the casing as deep as possible Immediate! Not exposing the hole too long Good cement integrity along the casing annulus Slide 3 of 10
Casing Drilling Technology Drilling technology which simultaneously drilling and casing the well The casing is used to transmit the mechanical and hydraulic energy from surface to the bit Slide 4 of 10
Plastering Effect The combined forces of high annular velocity, pipe rotation and the proximity of the casing wall to the borehole results in drill cuttings being crushed and smeared against the formation, creating a much less permeable wall cake. (Karimi, et al., 2011) Slide 5 of 10
Casing Drilling Technology as a Solution Set the casing as deep as possible Full Rotational Capability Drillable Alloy Casing Bit Immediate! Not exposing the hole too long Good cement integrity along the casing annulus Plastering Effect Slide 6 of 10
Pre-Execution Engineering Work Bit Design T&D and Casing Stress & Fatigue Analysis Dynamics Analysis Slide 7 of 10
Operation Overview Drilled and Reamed with casing in Total Loss Condition Stopped at 850 m MD considering: Surface torque limit (Top Drive Saver Sub) Closed to 20% RT casing fatigue calculation Risk of sidetrack as surface torque closed to on-bottom drilling Successful Drill Out Operation Good cementing verified by 5 mv CBL reading Slide 8 of 10
What was the impact? successfully set the casing 320 m deeper than the point of casing started taking significant weight Having a good cement integrity across the 13-3/8 casing section Saved 1 (one) unnecessary clean out trip Helped not exposing the borehole for a long time, reducing the stuck clean out BHA situation Significant Operating Time & Cost Saving Eliminated the requirement of having a casing/liner tieback system Smooth 12-1/4 section drilling as the problematic zone had been sealed off Slide 9 of 10
Summary Casing Drilling Technology Saved The Well!! Nondirectional Casing Drilling for On-Bottom Drilling Future Casing Drilling Opportunity Directional Casing Drilling System Liner Drilling System to deliver the perforated liner to bottom Slide 10 of 10
THANK YOU Questions / Discussions