Packer and Seal Arrangements

The packer and seal assembly provides the pressure integrity between the producing formations and the tubing. Unfortunately, this equipment also limits tubing movement, which results in stress increases. Various types and combinations of packer systems are currently used.

Drilling Packer
Fig. 13-6 Bending stresses

The completion type affects the stresses in the tubing. A single completion has a bottom packer. Multiple completions normally use additional packers that restrict vertical and buckling tubing movement. Gravel pack completions are similar to single completions with respect to tubing stress.

Packers. A packer is a device that seals the tubing-casing annulus and forces produced liuids into the tubing. The exterior of the packer contains slips to prevent packer movement and a sealing element. A permanent packer is shown in Fig. 13-7, The siips are rated for tensile loading and should be evaluated when the packer is selected.

The sealing rubber is typically a nitrile compound with a 60-70 durometer hardness. High formation temperatures may necessitate the use of harder rubbers (80-90 hardness). In addition. K-Ryte® (Dupont) or equivalent sealing elements must be used in sour gas environments when certain corrosion inhibitors are used.

The size of the packer bore is an important variable in buckling calculations. It is seldom the same size as the tubing outer diameter. Fig. 13-8 shows the possible variations in bore diameters for a S'/i-in. Baker packer. Table 13-1 illustrates the packer bore sizes for various Baker Model D packers.

Model Baker Permanent Packer

Packer-to-tubing seal

Back-up rings

Packer Model

Packer-to-casing seal element

Back-up rings

Packer-to-tubing seal

Packer-to-casing seal

Back-up rings element

Back-up rings

Fig. 13-7 Permanent packer (Courtesy Baker Packers)

Casing Packer Baker

Fig. 13—8 Packer bore size variations for various Baker packers in the 5!/2-in. casing size (20-23 lb/ft)

Table 13-1 Packer Bore Sizes for Baker

Model D Packers

Casing Size,

Casing Weight,

Bore Size,

in.

lb/ft

in.

4,5

9,5-16.6

1.312

5

15-21

1.968

11.5-13

1.312

5.5

26

0.984

13-23

1.968

6

14-26

2.375

6.625

17-32

2,406

7

17-38

2.375

7.625

24-39

2.375

8.625

24-49

2.468

9.625

32.3-47

3.875

10.75

32.75-81

3,875

1 1.75

38-60

3.875

13.375

48-72

4.875

Seal Assembly. The seal assembly attaches to the bottom of the tubing and provides the pressure seal between the tubing and the packer. The standard seal assembly contains two 1-ft seal units. The locator assembly. Fig. 13-9, allows upward tubing movement and prevents downward movement when the locator is set on the packer. The anchored assembly. Fig. 13-10. screws into the packer and prevents any vertical movement

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Responses

  • sandra diederich
    What is drilling packer?
    8 years ago
  • primula
    What is durometer reading for element of the packer?
    7 years ago

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