Erosion Management

  1. Subsea
  2. Production Facilities
  3. Production Engineering
  4. Erosion Management
  5. Asset Integrity


Erosion management includes the erosion monitoring and erosion mitigation methods.

Erosion Monitoring

The following methods are used for erosion monitoring on steel pipes or special tab erosion:

  • Ultrasonic gauges are used to clamp to the external surface of the pipe. They send out an ultrasonic pulse tomeasure the thickness and the material loss from which to determine the erosion severity. The method is sensitive to the noise from other sources; also the primary limitation of thismethod is that it only checks a limited local region of the pipe.
  • Weight-loss coupons made of the same or similar material as the pipe being monitored are installed and periodically retrieved and weighed. They provide only discrete monitoring and are unsuitable for subsea engineering equipment.
  • Electrical resistance probes measure the accumulated erosion as an increase in electrical resistance on a known cross section. Calibration and temperature changes are of concern.
  • Electrochemical probes determine the erosion rate through measurement of the linear polarization resistance between electrodes through a conductive electrolyte flowing inside the pipe. This method is suitable only for conductive liquids such as water, or oil systems with high water cuts.

Erosion Mitigating Methods

A number of measures can be taken to mitigate erosion, as discussed next.

Reduction of Production Rate

Reducing the production rate includes reducing the flow velocity and sand production rate. However, this has adverse financial implications.

Design of Pipe System

Minimizing the flow velocity and avoiding sudden changes (e.g., at elbow, constrictions, and valves) in the flow direction should be given much attention in order to reduce the severity of any erosion. Blind tees are generally perceived as being less prone to erosion than elbows, so the use of full-bore valves and blind tees in place of elbows can reduce erosion problems. Also, the flow regime has an impact on erosion problems and slugging flows can be particularly damaging; therefore, slug catchers may be appropriate for reducing the severity of any erosion.

Increasing Wall Thickness

Thick-walled pipes are often used to increase the wear life of a pipe system. However, the thick wall thickness reduces the pipe bore, which in turn elevates flow velocities and increases the erosion rate, particularly with small-bore pipe systems.

Specialized Erosion-Resistant Materials

Generally, in oil and gas production systems nearly all of the components will be made of ductile metals, although other materials such as plastic and rubber may also be used. Material properties have a significant effect on erosion problems. If erosion problems are suspected, specialized erosionresistant materials such as tungsten carbide can be used.

The primary factor of ductile materials in controlling erosion is their hardness. Consequently, steels are more resistant than other softer metals. In vulnerable components, specialized materials such as tungsten carbides, coatings, and ceramics are often used. These materials are generally hard and brittle and have a super erosion resistance to steel (often orders of magnitude better). However, some coated materials’ resistance may rapidly reduce once the coating or its substrate fails. Brittle materials erode in a different manner. Impacts on brittle materials abrade the surface, and erosion increases linearly with the impact angle, until reaching a maximum for perpendicular impacts.

References

[1] E.S. Venkatesh, Erosion Damage in Oil and Gas Wells, Proc. Rocky Mountain Meeting of SPE, Billings, MT (1986) 489–497. May 19-21.

[2] N.A. Barton, Erosion in Elbows in Hydrocarbon Production System: Review Document, Research Report 115, HSE, ISBN 0 7176 2743 8, 2003.

[3] American Petroleum Institute, Recommended Practice for Design and Installation of Offshore Production Platform Piping Systems, fifth ed., API- RP-14E, 1991.

[4] Det Norsk Veritas, Erosive Wear in Piping Systems, DNV- RP- O501 (1996).

[5] A. Huser, O. Kvernvold, Prediction of Sand Erosion in Process and Pipe Components, Proc. 1st North American Conference on Multiphase Technology, Banff, Canada, pp. 217–227 (1998).

[6] M.M. Salama, E.S. Venkatesh, Evaluation of API RP 14E Erosional Velocity Limitation for Offshore Gas Wells, OTC 4485, Offshore Technology Conference, Houston, Texas, 1983.

[7] S.J. Svedeman, K.E. Arnold, Criteria for Sizing Multiphase Flow Lines for Erosive/ Corrosive Service, SPE 26569, 68th Annual Technical Conference of the Society of Petroleum Engineers, Houston, Texas, 1993.

[8] M.M. Salama, An Alternative to API 14E Erosional Velocity Limits for Sand Laden Fluids, OTC 8898, pp. 721 –733, Offshore Technology Conference, Houston, Texas (1998).

[9] P.D. Weiner, G.C. Tolle, Detection and Prevention of Sand Erosion of Production Equipment. API OSAPR Project No 2, Research Report, Texas A&M University, College Station, Texas, 1976.

[10] T. Bourgoyne, Experimental Study of Erosion in Diverter Systems. SPE/IADC 18716, Proc SPE/IADC Drilling Conference, New Orleans, 28 February - 3 March, pp. 807–816, 1989.

[11] B.S. McLaury, S.A. Shirazi, Generalization of API RP 14E for Erosive Service in Multiphase Production, SPE 56812, SPE Annual Technical Conference and Exhibition, Houston, Texas, 1999.

[12] S.A. Shirazi, B.S. McLaury, J.R. Shadley, E.F. Rybicki, Generalization of the API RP 14E Guideline for Erosive Services, SPE28518, Journal of Petroleum Technology, August 1995 (1995) 693–698.

[13] B.S. McLaury, J. Wang, S.A. Shirazi, J.R. Shadley, E.F. Rybicki, Solid Particle Erosion in Long Radius Elbows and Straight Pipes, SPE 38842, SPE Annual Technical Conference and Exhibition, San Antonio, Texas, 1997.

[14] J. Tronvoll, M.B. Dusseault, F. Sanfilippo, F.J. Santarelli, The Tools of Sand Management, SPE 71673, 2001, SPE Annual Technical Conference and Exhibition held in New Orleans, Louisiana, 2001.


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