Tapered-Bean Steam Chokes Revisited
- Suzanne Castrup (Integrated Sciences Group) | Faisal Latif (Vintage Production California LLC) | Ali Al Kalbani (Occidental Petroleum Corporation)
- Document ID
- Society of Petroleum Engineers
- SPE Production & Operations
- Publication Date
- May 2012
- Document Type
- Journal Paper
- 205 - 210
- 2012. Society of Petroleum Engineers
- 5.4.6 Thermal Methods
- Steam Flow Control, Steam Chokes, Tapered-bean Chokes, Critical Flow
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- 434 since 2007
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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.
|File Size||430 KB||Number of Pages||6|
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