Wells – Processes – Operating valve – closure – or changeable restrictor in a well
Reexamination Certificate
1999-05-12
2001-02-06
Will, Thomas B. (Department: 3673)
Wells
Processes
Operating valve, closure, or changeable restrictor in a well
C166S065100, C166S091100, C367S083000
Reexamination Certificate
active
06182764
ABSTRACT:
BACKGROUND
The invention relates to generating commands for a downhole tool.
Referring to
FIG. 1
, for purposes of measuring characteristics (e.g., formation pressure) of a subterranean formation
31
, a tubular string
10
may be inserted into a wellbore which extends into the formation
31
. In order to test a particular region, or zone
33
, of the formation
31
, the string
10
may include a perforating gun
30
that is used to penetrate a well casing
12
and form fractures
29
in the formation
31
. To seal off the zone
33
from the surface of the well, the string
10
typically includes a packer
26
that forms a seal between the exterior of the string
10
and the internal surface of the well casing
12
. Below the packer
26
, a recorder
11
of the string
10
takes measurements of the formation
31
.
The tool
21
typically has valves to control the flow of fluid into and out of a central passageway of the string
10
. An in-line ball valve
22
is used to control the flow of well fluid from the formation
31
up through the central passageway of the test string
10
. Above the packer
26
, a circulation valve
20
is used to control fluid communication between an annulus
16
surrounding the string
10
and the central passageway of the string
10
.
The ball valve
22
and the circulation valve
20
can be controlled by commands (e.g., “open valve” or “close valve”) that are sent downhole. Each command is encoded into a predetermined signature of pressure pulses
34
(
FIG. 2
) transmitted downhole to the tool
21
via hydrostatic fluid present in the annulus
16
. A sensor
25
of the tool
21
receives the pressure pulses
34
, and the command is extracted. Electronics and hydraulics of the string
10
then operate the valves
20
and
22
to execute the command.
For purposes of generating the pressure pulses
34
, a port
18
in the casing
12
extends to a manually operated pump (not shown). The pump is selectively turned on and off by an operator to encode the command into the pressure pulses
34
. A duration T
0
(e.g., 1 min.) of the pulse
34
, a pressure P
0
(e.g., 250 p.s.i.) of the pulse
34
, and the number of pulses
34
in succession form the signature that uniquely identifies the command.
SUMMARY
In one embodiment, a system is used with a well that has a downhole tool which is responsive to a stimulus. The system includes a fluid circulation path that is connected to circulate a fluid and a flow restrictor that is connected in the fluid circulation path and located at the surface of the well. A controller causes the flow restrictor to selectively alter flow of the fluid in the circulation path, and a link is coupled to the circulation path to furnish the stimulus to the downhole tool in response to the alteration of flow by the flow restrictor.
Advantages and other features of the invention will become apparent from the following description, drawing and claims.
REFERENCES:
patent: 4896722 (1990-01-01), Upchurch
patent: 4953618 (1990-09-01), Hamid et al.
patent: 5515336 (1996-05-01), Chin et al.
patent: 5963138 (1999-10-01), Gruenhagen
patent: 0 344 060 A2 (1989-11-01), None
patent: 0 604 134 A1 (1994-06-01), None
Kreck John
Schlumberger Technology Corporation
Trop Pruner & Hu P.C.
Will Thomas B.
LandOfFree
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