Seal for a joint or juncture – Seal between relatively movable parts – Relatively rotatable radially extending sealing face member
Reexamination Certificate
2000-02-03
2002-06-18
Knight, Anthony (Department: 3626)
Seal for a joint or juncture
Seal between relatively movable parts
Relatively rotatable radially extending sealing face member
C277S336000, C277S337000, C277S338000, C277S339000, C277S342000
Reexamination Certificate
active
06406028
ABSTRACT:
BACKGROUND
The invention relates to a seal stack.
Referring to
FIG. 1
, a downhole tool
14
may be used to perform such functions as measuring performance of a subterranean well
10
and controlling production from the well
10
. As examples, the tool
14
may be part of a test string
12
, part of a drill string, connected to a wireline, or connected to a slickline.
In the course of its operation, the tool
14
may be subject to a large range of temperatures and a large range of pressures. For example, the temperatures that the tool
14
may experience may vary from approximately 60° Fahrenheit (F.) to approximately 500° F., and the pressures may vary from approximately a few pounds per square inch (psi) to approximately 30,000 psi. These variations, in turn, may affect the performance of seals of the tool
14
. As an example, referring to
FIG. 2
, the tool
14
may include a mandrel
22
that may move in response to pressure differences to actuate a downhole valve (not shown), for example. More particularly, the mandrel
22
may have a piston head surface
24
that is contact with fluid in one chamber
26
and another piston head surface
20
that is contact with fluid in another chamber
27
. In this manner, the pressure differential between the two chambers
26
and
27
influences movement of the mandrel
22
.
To isolate the two chambers
26
and
27
from each other, the tool
14
may include an annular seal
30
(a seal stack, for example) that is located in an annular cavity of the mandrel
22
and between the two piston head surfaces
20
and
24
. The type of seal
30
that is used may be selected based on the expected downhole temperatures and pressures. However, the tool
14
may be used in applications that cause the tool
14
to experience a wide range of temperatures and pressures. For example, oil and gas exploration is currently advancing into the traditionally deeper and harder to reach areas in which pressures may be near 20,000 psi, and the temperature may be over 400° F. Furthermore, operation of the tool
14
may increase the pressure to near 30,000 psi. Therefore, the seal
30
may be required to operate over a wide range of conditions.
Thus, there is a continuing need for a seal that addresses one or more of the problems stated above.
SUMMARY
In an embodiment of the invention, a seal stack includes one or more first seals that are adapted to seal in at least a first range of temperatures. The seal stack also includes a second seal that is adjacent to at least one of the first seals. The second seal is adapted to seal in at least a lower range of temperatures than the first range of temperatures.
Advantages and other features of the invention will become apparent from the following description, drawing and claims.
REFERENCES:
patent: 4234197 (1980-11-01), Amancharla
patent: 4811959 (1989-03-01), Bullard et al.
patent: 5306021 (1994-04-01), Morvant
patent: 5309993 (1994-05-01), Coon et al.
Schlumberger Technology Corporation
Trop Pruner & Hu P.C.
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