Wells – Processes – With indicating – testing – measuring or locating
Patent
1998-02-05
2000-11-28
Schoeppel, Roger
Wells
Processes
With indicating, testing, measuring or locating
166130, 166131, 166141, 166151, 16625017, 166386, 166387, E21B 4700
Patent
active
061522244
DESCRIPTION:
BRIEF SUMMARY
This invention relates to apparatus for use in downhole operations. In particular, but not exclusively, the apparatus is intended for use in completion testing and in operations which take place immediately following completion testing.
In the oil and gas exploration and extraction industries, deep bores are drilled to gain access to hydrocarbon-bearing strata. The section of bore which intersects this strata or "production zone" is typically provided with a steel "liner", while the section of bore extending to the surface is lined with steel "casing". Oil and gas is extracted from the production zone through production tubing extending through the casing from the upper end of the liner. The production tubing is formed of a string of threaded sections or "subs" which are fed downwards from the surface, additional subs being added at the surface until the string is of the desired length. As the string is assembled and fed into the bore its pressure integrity, or "completion", is tested at regular intervals. Such testing is also carried out on the complete string. The testing is accomplished by pressurising the internal bore of the string. Of course this requires that the string bore is sealed at its lower end. However, it is desirable that the string fills with well fluid as it is lowered into the bore. The applicant has previously developed a tool to accommodate these conflicting requirements, as described in GB-A-2 272 774. The tool includes a sleeve mounted on a tubular body which forms part of the string. A port is provided in the body and is normally aligned with a port in the sleeve to permit well fluid to flow, from the annulus, into the string. However, on pressurising the string bore, by pumping fluid down the bore from the surface, the resulting pressure force acts on a piston defined by the sleeve to move the sleeve and seal the body port. The completion of the string may then be tested. On the pressure being bled off, a spring returns the sleeve to the initial position and opens the ports.
A string may carry a number of fluid pressure actuated tools or fittings, including packers for locating or sealing a production string within a casing. Valves or plugs may also be provided on the lower end of the tubing and may be opened or removed once the packers have been set, to permit formation testing and also to permit formation fluid to flow upwardly to the surface through the production tubing. Typically, packers are mounted on the exterior of the string and are inflated or otherwise set, when the packer is in the desired location, to engage the casing. However, during completion testing any packers mounted on the string may be prematurely set by the application of the elevated completion testing pressures. Clearly this is not desirable, and may create difficulties as the string is moved downwardly and further into the bore. Further, the opening or removal of valves or plugs following setting of the packers may require running in of an appropriate tool on wireline or coiled tubing, which will involve additional time and expense.
It is among the objects of aspects of the present invention to obviate or mitigate one or more of these disadvantages.
According to the present invention there is provided downhole apparatus comprising: a tubular body; a valve for controlling the flow of well fluid through a first port in the tubular body, the port being in communication with a fluid pressure actuated device; and a valve actuator mounted on the body and moveable relative thereto, to open the valve, by application of well fluid pressure.
According to another aspect of the present invention there is provided a method of selectively actuating a pressure actuated downhole tool, the method comprising: providing a valve for controlling flow of well fluid through a port in a tubular body, the port being in communication with a fluid pressure actuated device; providing a valve actuator on the tubular body; applying well fluid pressure to the actuator to open the valve and permit communication of said fluid pressure t
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patent: 4817723 (1989-04-01), Ringgenberg
patent: 5291947 (1994-03-01), Stracke
patent: 5396953 (1995-03-01), Holder et al.
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