Drilling Difficult Formations Efficiently With the Use of an Antistall Tool
- Knut Sigve Selnes (StatoilHydro) | Carl C. Clemmensen (Halliburton) | Nils Reimers (Tomax)
- Document ID
- Society of Petroleum Engineers
- SPE Drilling & Completion
- Publication Date
- December 2009
- Document Type
- Journal Paper
- 531 - 536
- 2009. Society of Petroleum Engineers
- 4.1.9 Tanks and storage systems, 1.10.1 Drill string components and drilling tools (tubulars, jars, subs, stabilisers, reamers, etc), 5.3.4 Integration of geomechanics in models, 4.3.4 Scale, 1.10 Drilling Equipment, 1.12.6 Drilling Data Management and Standards, 1.6 Drilling Operations, 1.1 Well Planning, 1.12.1 Measurement While Drilling, 5.6.1 Open hole/cased hole log analysis, 1.6.1 Drilling Operation Management, 3.3.4 Downhole Monitoring and Control, 1.5 Drill Bits
- stick-slip, shock, vibrations, dynamics, bit
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Antistall technology (AST) is a mechanical downhole solution that aims to adjust the drilling torque automatically in real time. Originally, the tool was developed by Tomax AS for coiled-tubing applications where it has proven its ability to successfully reduce vibrations, motor stalls, equipment failures, and general wear, in addition to increasing the penetration rate and run length (Dagestad et al. 2006). The tool was then developed further based on the need for a similar solution for rotary drilling. The goal was to eliminate cutter-induced torque variations and string stalls in difficult formations and resultant harmful effects. Prototype AST tools were made in sizes ranging from 6¾ to 8¼ in. The tools were then run in test wells and later in field operations with a variety of tool configurations until the database, in addition to two controlled trials, counted 25 regular jobs--mainly on the Norwegian Continental Shelf. The paper describes in detail, both based on theory and on field experience, how the bit-induced torque fluctuations are significantly decreased to improve penetration, and how bottomhole-assembly (BHA) damage is prevented to increase run lengths.
Along with the introduction and development of fixed-cutter drill-bit polycrystalline-diamond-compact (PDC) technology in the early 1980s, the drilling industry has also seen continuous development of more sophisticated drilling and formation-evaluation systems containing an increasing number of electronic components in the instrumented part of the BHA. These advanced downhole-drilling systems enable faster drilling, high-precision well bore placement, and longer reach, but, because of their complexity and sophisticated design, they are also more prone to premature failure caused by high energy shocks and vibrations downhole. While being highly effective, the PDC bits have a proven potential to produce dynamic forces and energy shocks at levels at which they become destructive to the bit itself, the instrumented BHA, and the drillstring connections (Fear et al. 1997). The industry's response to this challenge has been to develop stronger downhole tools equipped with sensors for measuring and monitoring the various downhole dynamic parameters. The drilling process is then controlled on the basis of this information (Robnett et al. 1999). The principal idea behind the AST is to provide active downhole control of the rock-cutting process by diverting energy from the drilling process and using it to prevent dynamic forces from reaching destructive levels and thereby preserving the drillstring components and optimizing rock-cutting efficiency. To emphasize this point, one could draw a comparison with modern motor-racing technology where it has proved highly beneficial to both performance and durability to actively balance the amount of power transferred to the wheels against the overall stability of the vehicle.
|File Size||752 KB||Number of Pages||6|
Dagestad, V., Mykkeltvedt, M., Eide, K., and Reimers, N. 2006. First Field Results forExtended-Reach CT-Drilling Tool. Paper SPE 100108 presented at theSPE/ICoTA Coiled Tubing Conference and Exhibition, The Woodlands, Texas, USA,4-5 April. doi: 10.2118/100108-MS.
Fear, J.M., Abbassian, F., Parfitt, S.H.L., and McClean, A. 1997. The Destruction of PDC Bits by SevereSlip-Stick Vibration. Paper SPE 37639 presented at the SPE/IADC DrillingConference, Amsterdam, 4-6 March. doi: 10.2118/37639-MS.
Richard, T., Detournay, E., Fear, M., Miller, B., Clayton, R., and Matthews,O. 2002. Influence of bit-rockinteraction on stick-slip vibrations of PDC bits. Paper SPE 77616 presentedat the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA,29 September-2 October. doi: 10.2118/77616-MS.
Robnett, E.W., Hood, J.A., Heisig, G., and Macpherson, J.D. 1999. Analysis of the Stick-Slip PhenomenaUsing Downhole Drillstring Rotation Data. Paper SPE 52821 presented at theSPE/IADC Drilling Conference, Amsterdam, 9-11 March. doi: 10.2118/52821-MS.