TY - CONF TI - Drill-string design for directional wells AB - This paper is concerned with predicting the tension and torsion loads on drill strings in directional wells and with adjusting the string design or well plan to provide adequate strength. Drill-string drag is the incremental force that is required to move the pipe up or down in the hole; torque is the moment required to rotate the pipe. Drag forces are usually given relative to the string weight measured with the string roating but not reciprocating. Measured from the roating string weight, the pick-up drag is usually slightly greater than the slack-off drag. The magnitudes of torque and drag are related in any particular well; high drag forced and exessive torque loads normally occur together. There are a number of phenomena wich contribute to torque and drag. Included are tight hole conditions, sloughing hole, keyseats, differential sticking, cuttings build up due to poor hole cleaning and sliding wellbore friction. With the exception of sliding friction, these causes are associated with problem conditions in the wellbore. Conversely, in wells with good hole conditions, the primary source of torque and drag is sliding friction. This paper is only concerned with the torque and drag caused by sliding friction. The cabability to predict frictional loads on drill pipe has two main benefits. First, more complete knowledge of drill-string loading allows use of improved drill-string design techniques. Drill-string components can be chosen using a systematic approach considering the force involved. Second, deep, highly-deviated wells can be planned to minimize torque and drag. Use of torque and drag as a criteria to select the most appropriate well path will help ensure successful drilling operations to total depth. 1 fig., 2 tabs. (Author). AU - "Dawson, R" AU - "Corbett, K T [Exxon Production Research Co., Houston, TX (USA)]" KW - "42 ENGINEERING" KW - "DRILL PIPES" KW - "LOAD ANALYSIS" KW - "WELLS" KW - "DIRECTIONAL DRILLING" KW - "DRAG" KW - "SIMULATION" KW - "TENSILE PROPERTIES" KW - "TORSION" KW - "DRILLING" KW - "DRILLING EQUIPMENT" KW - "EQUIPMENT" KW - "MECHANICAL PROPERTIES" KW - "PIPES" KW - "422000* - Engineering- Mining & Underground Engineering- (1980-)" DO - https://doi.org/ UR - PB - CY - Norway PY - 1983 DA - 1983-01-01 LA - English J2 - [] VL - C1 - Norsk Petroleumsforening, Oslo (Norway) C2 - C3 - NEI-NO-101; CONF-8310456- C4 - C5 - NTIS (US Sales Only), PC A21/MF A01 L3 - Conference: 1. Northern European drilling conference, Kristiansand (Norway), 24-26 Oct 1983; Related Information: In: First Northern European drilling conference, Kristiansand, Norway, October 24-26, 1983, 491 p. ER -