Influence of Drilling Along Pilot Holes on Drilling Performance and Effective Rock Strength
This study investigates the intricate relationship between bit rock interactions and drilling parameters for multiple-diameter hole drilling scenarios. Two sets of experiments were conducted in the Drilling Technology Laboratory at Memorial University of Newfoundland (DTL-MUN) using a fully instrume...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
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| Series: | Applied Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-3417/15/1/32 |
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| Summary: | This study investigates the intricate relationship between bit rock interactions and drilling parameters for multiple-diameter hole drilling scenarios. Two sets of experiments were conducted in the Drilling Technology Laboratory at Memorial University of Newfoundland (DTL-MUN) using a fully instrumented Large-scale laboratory Drilling Simulator (LDS). The study contained two critical stages. Pre-coring operations using various diameter coring bits were completed to ensure thorough analysis. Next, drilling using a 5-cutter Polycrystalline Diamond Compact (PDC) bit with a larger diameter than all pre-cored holes, at constant Weight on Bit (WOB) and Revolution per Minute (RPM), was performed. The type of rock used in the experiments is a high-strength gabbro formation. Results indicate that pre-cored holes exhibited higher Rates of Penetration (ROP) than un-pre-cored holes, reflecting improved drilling performance and higher torque due to reduced bit–rock interaction area. A distinct relationship was observed between bit–rock interactions, torque, ROP, Mechanical Specific Energy (MSE), and applied WOB in multi-diameter drilling. ROP decreased as the pilot hole diameter decreased due to increased bit–rock interaction. The recorded data of WOB and the torque responses showed a decrease in amplitude as the bit–rock interface area increased, suggesting a positive interaction between drilling efficiency and downhole conditions. The modified Maurer model found a correlation between increased pilot hole diameter and decreased effective rock strength. These results highlight the significance of conducting a thorough drilling parameter analysis and the need for additional study to clarify the underlying mechanisms influencing drilling performance in multi-diameter hole drilling scenarios. |
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| ISSN: | 2076-3417 |