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Institutional Repository [SANDBOX]
Technical University of Crete
Technical University of Crete
EN
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EL
| URI | http://purl.tuc.gr/dl/dias/61E8759E-CB0B-44D2-B510-07DFFE41FC8F | - |
| Identifier | http://www.mred.tuc.gr/home/kelessidis/publications/14.pdf | - |
| Language | en | - |
| Title | Hydraulic parameters affecting cuttings transport for horizontal coiled tubing drilling | en |
| Creator | Kelesidis Vasilis | en |
| Creator | Κελεσιδης Βασιλειος | el |
| Creator | Mpandelis G. E. | en |
| Content Summary | A niche market for the exploration and development of oil and gas fields is drilling horizontal wells with continuous tubing, the coiled tubing. Among the many challenges that require engineering solutions is a fluid mechanics challenge, the effective transport of the solid particles from downhole to the surface. This is achieved with fluid circulation through the annulus and the most difficult section is the horizontal section of the well. Fluids used are normally non-Newtonian and analysis indicates that the fluids should have the right rheological properties and should flow at the required flow rates. Liquids with appropriate rheological properties and flowing at sufficient flow rates carry the solids, which normally move on the bottom side of the annulus. If conditions are not right, the solids form a bed, which can become stationary thus making progress in drilling difficult and requiring frequent and expensive cleaning activities. In this paper we present first results of the ongoing research project aiming at shedding additional light into the parameters affecting cuttings transport in horizontal wells. Experiments were performed with water and aqueous solutions of Carboxy-Methyl-Cellulose (CMC) in a recirculating flow loop with a non rotating concentric annulus. The characteristics of the flow patterns and the particle - liquid interactions at the various flow rates that have been visually observed are presented and described in detail and the issues that they have arisen from this research are discussed. Particles were glass beads with diameter of 2mm and density of 2,59g/cm3 and with solids concentration of 0,4 to 0,6% w/v. The most significant parameter for no bed formation is flow rate. At low liquids rates particles form a moving bed which can be eroded if the flow rate is increased. If conditions are right, accumulations of solids (“blobs”) are formed, about 20cm long and covering almost half the height of the annulus. Once a critical height is reached and the velocity of the liquid above the bed is sufficient, it is eroded and the whole ‘blob’ is moved, by erosion, further along the annulus. The erosion velocity is higher than the velocity predicted using Kelvin – Helmholtz instability theory. At higher flow rates, but not sufficiently high for full solid suspension, the solids do not deposit on the wall but flow in streaks near the bottom wall of the annulus. A plausible explanation for the solids staying in the low speed region is that they are held there by the turbulent sweeps known to exist near the wall in turbulent flow. No solids are observed in most of the annulus flow area for all flow patterns studied, thus pointing out to the fact that the solid - diffusion equation, normally used to describe the phenomenon in slurry transportation, should not be used, at least for the conditions of this research | en |
| Type of Item | Πλήρης Δημοσίευση σε Συνέδριο | el |
| Type of Item | Conference Full Paper | en |
| License | http://creativecommons.org/licenses/by-nc-nd/4.0/ | en |
| Date of Item | 2015-11-12 | - |
| Date of Publication | 2004 | - |
| Bibliographic Citation | V.C. Kelessidis, G.E. Bandelis, "Hydraulic Parameters Affecting Cuttings Transport For Horizontal Coiled Tubing Drilling", in 7th National Congress on Mechanics, 2004. | en |
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