TECHNICAL DATA

Determining Minimum Plug Length for Long-Term Service Live

  1. Determine the minimum plug length using the PLUG LENGTH TABLE below.
  2. Determine the minimum plug length using the PLUG LENGTH EQUATION below.
  3. Use the longer of the two lengths.

PLUG LENGTH TABLE
Length Needed to Assure Long-Term Hydraulic Seal
Deviation at Plug Depth API Casing Sizes
5" & 5-1/2" csg 7" csg 7-5/8" csg 9-5/8" csg
0° 15 ft (4.6 m) 20 ft (6.1 m) 20 ft (6.1 m) 25 ft (7.6 m)
30° 18 ft (5.5 m) 23 ft (7.0 m) 25 ft (7.6 m) 30 ft (9.1 m)
60° 21 ft (6.39 m) 29 ft (8.8 m) 32 ft (9.8 m) 40 ft (12.2 m)
70° 26 ft (7.9 m) 35 ft (10.7 m) 40 ft (12.2 m) 50 ft (15.2 m)

 

PLUG LENGTH EQUATION

l = 

 DP x CSG OD x DEV
       5 x Ts

l = minimum plug length (ft)
DP = differential pressure (psid)
CSG OD = casing o.d. (inches)

 Ts = plug-to-csg shear bond @ 24 hr. (psi)
        (see below)
DEV = deviation factor (1 @ 0°, 1.2 @ 30°, 1.6
             @ 60°, 2.0 @ 70°)

Contact HPI about the application of this information to your specific plug-back operations.

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