The current practice for eliminating erosional problems in piping systems is to limit the flow velocity $Ve$ to that established by the recommended practice API RP 14E based on an empirical constant $(C$-factor) and the fluid mixture density $ρm$ as follows: $Ve=C/ρm.$ The API criterion is specified for clean service (noncorrosive and sand-free), and it is noted that the $C$-factor should be reduced if sand or corrosive conditions are present. The validity of the equation has been challenged on the basis that the API RP 14E limits on the $C$-factor can be very conservative for clean service and is not applicable for conditions when corrosion or sand are present. Extensive effort has been devoted to develop an alternative approach for establishing erosional velocity limits for sand-laden fluids. Unfortunately, none of these proposals have been adopted as a standard practice because of their complexity. This paper will review the results of these studies and proposes an alternative equation that is as simple as the API 14E equation. This alternative equation has the following form: $Ve=SDρm/W.$ The value of the $S$-factor depends on the pipe geometry, i.e., bend, tee, contraction, expansion, etc. Using the units for mixture flow velocity $Ve$ in m/s, fluid mixture density $ρm$ in $kg/m3,$ pipe diameter ($D$) in mm and sand production $W$ in kg/day, the value of the $S$-factor is 0.05 for pipe bends. The accuracy of the proposed equation for predicting erosion in pipe bends for fluids containing sand is demonstrated by a comparison with several multi-phase flow loop tests that cover a broad range of liquid-gas ratios and sand concentrations. [S0195-0738(00)00202-8]

1.
API, 1981, “API RP 14E Recommended Practice for Design and Installation of Offshore Production Platform Piping Systems,” 3rd Edition, American Petroleum Institute, Washington, DC, p. 22.
2.
API, 1991, “API RP 14E Recommended Practice for Design and Installation of Offshore Production Platform Piping Systems,” 5th Edition, American Petroleum Institute, Washington, DC, p. 23.
3.
Salama, M. M., 1998, “An Alternative to API 14 E Erosional Velocity Limits for Sand Laden Fluids,” Proc., Annual Offshore Technology Conference, OTC Paper 8898.
4.
Salama, M. M., and Venkatesh, E. S., 1983, “Evaluation of API RP 14E Erosional Velocity Limitations for Offshore Gas Wells,” Proc., 15th Offshore Technology Conference, Paper OTC 4485.
5.
Heidersbach, R., 1985, “Velocity Limits for Erosion-Corrosion,” Proc., 17th Offshore Technology Conference, Paper OTC 4974.
6.
Beggs
,
H. D.
, and
Brill
,
J. P.
,
1973
, “
A Study of Two-Phase Flow in Inclined Pipes
,”
J. Pet. Technol.
,
25
, No.
5
, pp.
607, 617
607, 617
.
7.
Rybicki, E., 1987, private communication, University of Tulsa, Tulsa, OK.
8.
Engel
,
O. G.
,
1955
, “
Water Drop Collisions with Solid Surfaces
,”
J. Res. Natl. Bur. Stand.
,
54
, No.
5
, pp.
281
298
.
9.
Gipson, F., 1989, “Petroleum Production Engineering, Pits and Pieces,” Manual of Southwest Petroleum Short Course, Texas Tech University, April 17–20.
10.
Deffenbaugh, D. M., and Buckingham, J. C., 1989, “A Study of the Erosional/Corrosional Velocity Criterion for Sizing Multi-Phase Flow Lines,” Southwest Research Institute Final Report, Project No. 04-2433, prepared for the Minerals and Management Service, U.S. Department of the Interior.
11.
Smart, J. S., 1990, “A Review of Erosion Corrosion in Oil and Gas Production,” Corrosion 90, Paper 10, NACE.
12.
Coker
,
A. K.
,
1990
, “
Understand Two-Phase Flow in Process Piping
,”
Chem. Eng. Prog.
,
86
, No.
11
, Nov. pp.
60
65
.
13.
Coulson, J. M., and Richardson, J. F., 1977, Chemical Engineering, 1, 3rd Edition, p. 91, Pergamon Press.
14.
Smart, J. S., 1991, “The Meaning of the API RP 14E Formula for Erosion/Corrosion in Oil and Gas Production,” Corrosion 91, Paper 468, NACE.
15.
Patton, C. C., 1993, “Are We Out of the Iron Age Yet?,” Corrosion 93, Paper No. 56, NACE.
16.
Erichsen, H., 1988, “Nipple, Lock, and Flow Coupling Recommendations and Subassembly Description for North Sea Wells,” private communications, Norske Conoco a.s.
17.
Camacho, R. A., 1988, “The Design, Construction, and Testing of a Liquid Impingement Apparatus and a Study of Metal Surfaces Eroded by Liquid Impingement,” M. S. thesis, The University of Tulsa, Tulsa, OK.
18.
Saetre, O., 1991, “Testing of Composite Pipes in High Velocity Seawater,” Volume III, Part B Proc., 10th International Conference on Offshore Mechanics and Arctic Engineering, ASME, eds., M. M. Salama et al., pp. 577–583.
19.
Salama, M. M., 1996, “Velocity Limits for Multi-Phase Piping,” unpublished internal report, Conoco Inc..
20.
Salama
,
M. M.
,
1993
, “
Erosional Velocity for Water Injection Systems
,”
Materials Performance, NACE
,
32
, No.
7
, pp.
44
49
.
21.
Greving, D., 1991, “Effect of Flow Velocity on the Performance of Selected Oil Field Corrosion Inhibitors in Vertical Tubing, Under Two-Phase Flow Conditions,” M. S. thesis, Mechanical Engineering, University of Tulsa, Tulsa, OK.
22.
Kvernvold, O., 1998, “ERBEND 2—Erosion in Pipe Bends,” Det Norske Veritas (DNV), Norway.
23.
Shirazi
,
S. A.
,
McLaury
,
B. S.
,
,
J. R.
, and
Rybicki
,
E. F.
,
1995
, “
Generalization of the API RP 14E Guidelines for Erosive Services
,”
J. Pet. Technol.
,
47
, No.
8
, pp.
693
698
.
24.
Lockett, T. J., Beech, P. M., Birchenough, P. M., McCarthy, P., Dawson, S. G. B., and Worraker, W. J., 1997, “Erosion/Corrosion in Sweet Multiphase Systems,” AEAT Report No. 1174, AEA Technology plc., UK.
25.
Svendeman, S. J., and Arnold, K. E., 1994, “Criteria for Sizing Multi-phase Flow Lines for Erosive/Corrosive Services,” SPE Prod. Facil.
26.
Birchenough, P. M., Dawson, S. G. B., Lockett, T. J., and McCarthy, P., 1995, “Critical Flow Rates Working Party,” Report No. AEA-TSD-0348, AEA Technology, UK.
27.
Kvernvold, O., and Sandberg, R., 1993, “Production Rate Limits in Two-Phase Flow Suystems: Erosion in Piping Systems for Production of Oil and Gas,” Technical Report No. 93-3252, Det Norske Veritas (DNV), Norway.
28.
Tolle, G. C., and Greenwood, D. R., 1977, “Design of Fittings to Reduce Wear Caused by Sand Erosion,” API OSAPER Project No. 6, American Petroleum Inst., Texas A&M Research Foundation.
29.
Weiner, P. D., and Tolle, G. C., 1976, “Detection and Prevention of Sand Erosion of Production equipment,” API OSAPER Project No. 2, American Petroleum Inst., Texas A&M Research Foundation.
30.
Bourgoyne, A. T., 1989, “Experimental Study of Erosion in Diverter Systems Due to Sand Production,” Proc., SPE/IADC Drilling Conference, New Orleans, LA, SPE/IADC 18716.