SPE Production & Operations
Volume 27, Number 2, May 2012, pp. 205-210

SPE-144615-PA

Tapered-Bean Steam Chokes Revisited

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DOI  More information 10.2118/144615-PA http://dx.doi.org/10.2118/144615-PA

Citation

  • Castrup, S., Latif, F., and Al Kalbani, A. 2012. Tapered-Bean Steam Chokes Revisited. SPE Prod & Oper  27 (2): 205-210. SPE-144615-PA. http://dx.doi.org/10.2118/144615-PA.

Discipline Categories

  • 4.11 Fundamental Research in Projects, Facilities and Construction

Keywords

  • Steam Chokes, Critical Flow, Steam Flow Control, Tapered-bean Chokes

Summary

Controlling and monitoring flow rates at continuous- and cyclic-steam-injection wells are important elements of reservoir-heat management. For nearly 30 years, critical flow chokes have proven to be the most reliable and cost-effective means of controlling steam injection into heavy-oil reservoirs. Flow-control efficiency has been further improved with tapered-bore bean inserts to achieve critical flow, with only 10 to 15% pressure loss across the choke.

For the past 10 years, the standard steam-choke assembly has consisted of a 1-in.-outer-diameter (OD) and 6-in.-long bean with a 6° tapered bore inserted inside a 2-in.-OD cage nipple or housing. Larger-diameter cage nipples and bean inserts have been required for steam-injection rates exceeding 500 B/D. More recently, a cost-cutting practice has been employed using shorter tapered beans inserted in standard choke assemblies.

This paper presents the results of field tests conducted to evaluate the effectiveness of shorter tapered-bean length for controlling steam-injection rates. Transition from subcritical to critical flow and overall pressure loss for different tapered-bean lengths are presented. A modified Thornhill-Craver flow-rate equation is provided for critical- and subcritical-flow regions. Calculated and measured rates are compared, and their relative uncertainties are assessed.

© 2012. Society of Petroleum Engineers

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History

  • Original manuscript received: 5 July 2011
  • Meeting paper published: 7 May 2011
  • Manuscript approved: 31 August 2011
  • Published online: 16 February 2012
  • Version of record: 1 May 2012