Low stress level drillstrings cut costs, perform better
- PinTec Services, Inc., Luling, TX (US)
Industry still drills far too many crooked holes and abuses poorly designed drillstrings, which suffer fatigue failure. This costly waste could be eliminated by using low-stress-level drillstrings, adequate packed hole assemblies and good drilling practices. This article discusses some of these problems. Fatigue failures in derricks, drawworks, engines, pumps, rotary tables and BOP stacks are not tolerated. Failures indicate that the steel parts are being worked or abused beyond the steel's endurance limit. In case of failure, the operating conditions are adjusted in order not to accumulate fatigue or, usually, a stronger piece of equipment is utilized that will not experience failures in the future. Drillstring fatigue failure and the drilling of a crooked hole plagued with doglegs, spirals and keyseats appears to be an accepted, expensive operating practice. The desire to increase penetration rates without regard for the endurance limit of components causes premature downhole failures in a high-stress-level drillstring. Drilling a crooked hole with doglegs, spirals and keyseats increases drilling stresses. Both fatigue failure and crooked hole problems can be minimized, if not eliminated, with the use of a low-stress-level drillstring.
- OSTI ID:
- 6776863
- Journal Information:
- World Oil; (United States), Vol. 207:4
- Country of Publication:
- United States
- Language:
- English
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