top drive
{{Short description|Mechanical device used to turn a drill string.}}
A top drive is a mechanical device on a drilling rig that provides clockwise torque to the drill string to drill a borehole. It is an alternative to the rotary table and kelly drive. It is located at the swivel's place below the traveling block and moves vertically up and down the derrick.{{Cite web |title=Top Drive |url=https://glossary.oilfield.slb.com/en/terms/t/top_drive |access-date=March 28, 2022 |website=Schlumberger Oilfield Glossary}}
Benefits
The top drive allows the drilling rig to drill the longer section of a stand of drill pipe in one operation. A rotary table type rig can only drill {{convert|30|ft|adj=on}} (single drill pipe) sections of drill pipe whereas a top drive can drill {{convert|60|-|90|ft|adj=on}} stands (double and triple drill pipe respectively, a triple being three joints of drillpipe screwed together), depending on the drilling rig size. Handling longer sections of drill pipe enables a drilling rig to make greater daily progress because up to {{convert|90|ft|adj=on}} can be drilled at a time, thus requiring fewer "connections" to add another {{convert|30|ft|adj=on}} of drill pipe.{{Cite web |title=8.4.2.2: Top-Drive Rig |url=https://www.e-education.psu.edu/png301/node/906 |access-date=March 28, 2022 |website=Penn State College of Earth and Mineral Sciences}} Another advantage of top drive systems is time efficiency. When the bit progresses under a kelly drive, the entire string must be withdrawn from the well bore for the length of the kelly in order to add one more length of drill pipe. With a top drive, the draw works only has to pick up a new stand from the rack and make up two joints. Making fewer and quicker connections reduces the risk of a stuck string{{Cite web |title=How Does a Top Drive Work? |url=https://www.rigzone.com/training/insight.asp?insight_id=332&c_id= |access-date=March 28, 2022 |website=Rig Zone}} from annulus clogging while drilling fluid is not being pumped.{{Cite web |date=September 21, 2021 |title=Top Drive |url=https://www.drillingmanual.com/top-drive-system-drilling-rig/ |access-date=March 28, 2022 |website=Drilling Manual |language=en-us}}
Variations
Several different kinds of top drives exist, and are usually classified based on the "Safe Working Load" (SWL) of the equipment and the size and type of motor used to rotate the drillpipe. For offshore and heavy duty use, a 1000 short ton unit would be used, whereas a smaller land rig may only require a 500 short ton device. Various sizes of hydraulic motors, or AC or DC electric motors, are available.{{cn|date=March 2022}}
Standards
The American Petroleum Institute has set standards for top drives in a number of its publications including:
- API 8A: Specification for Drilling and Production Hoisting Equipment (effective May 1998,{{Cite web |date=December 1997 |title=API Specification 8A: Specification for Drilling and Production Hoisting Equipment |url=https://standards.globalspec.com/std/1144154/API%2520SPEC%25208A |access-date=March 28, 2022 |website=Petroleum Services Logistics}} withdrawn February 2013){{Cite web |last=Whittaker |first=Don |date=August 1, 2012 |title=API Spec 8A |url=https://www.api.org/-/media/Files/Certification/Monogram-APIQR/0_API-Monogram-APIQR/Advisories-Updates/Updates/API_8A_Withdrawal-from-Monogram_Update_20120801.pdf?la=en&hash=9FBC67AA8108198602974F065565966F6308F4E3 |access-date=March 28, 2022 |website=American Petroleum Institute}}
- API 8B: Recommended Practice for Procedures for Inspections, Maintenance, Repair, and Remanufacture of Hoisting Equipment{{Cite web |date=May 2014 |title=API Recommended Practice 8B: Recommended Practice for Procedures for Inspections, Maintenance, Repair, and Remanufacture of Hoisting Equipment |url=https://www.api.org/~/media/files/publications/whats%20new/8b%20e8%20pa.pdf |access-date=March 28, 2022 |website=American Petroleum Institute}}
- API 8C: Specification for Drilling and Production Hoisting Equipment{{Cite web |date=April 2012 |title=API Specification 8C: Specification for Drilling and Production Hoisting Equipment |url=https://www.api.org/~/media/files/certification/monogram-apiqr/program-updates/8c%25205th%2520edition%2520purch%2520guidelines%2520r1%252020131024.pdf |access-date=March 28, 2022 |website=American Petroleum Institute |language=en}}
The International Organization for Standardization publishes a standard relating to top drives in:
- ISO 13535: Recommended Practice for Procedures for Inspections, Maintenance, Repair, and Remanufacture of Hoisting Equipment{{Cite web |date=2000 |title=ISO 13535:2000(en) Petroleum and natural gas industries — Drilling and production equipment — Hoisting equipment |url=https://www.iso.org/obp/ui/#iso:std:iso:13535:ed-1:v1:en |access-date=March 28, 2022 |website=International Organization for Standardization}}
See also
{{Portal|Energy}}
Notable manufacturers of top drives:
References
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