Power plants – Pressure fluid source and motor – Pulsator
Reexamination Certificate
1999-12-29
2001-08-07
Ryznic, John E. (Department: 3745)
Power plants
Pressure fluid source and motor
Pulsator
C060S591000, C091S001000, C166S344000
Reexamination Certificate
active
06269641
ABSTRACT:
FIELD OF THE INVENTION
A stroke control tool controlling the position of a subterranean well hydraulically actuated double acting piston and cylinder actuator assembly in which the position of the piston relative to the cylinder is moved by a remotely controlled first and second hydraulic lines. A hydraulic fluid measuring means is connected to one of the lines and is connected to the actuator assembly by an inelastic hydraulic line for accurately measuring and controlling the position of the actuator assembly.
BACKGROUND OF THE INVENTION
A subterranean well hydraulically actuated double acting piston and cylinder actuator assembly may be used for performing various functions in an oil or gas well. Proper operation of the actuator assembly requires that specific quantities of hydraulic fluid be pumped into the assembly for moving the position of the piston relative to the cylinder to a precise position. The hydraulic actuator assembly is remotely controlled by first and second hydraulic lines connected to opposite sides of the assembly. One such actuator is a SCRAMS hydraulically controlled actuator manufactured by, or available from, PES Incorporated of the Woodlands, Texas, and is useful as described in U.S. Pat. No. 5,957,207 for separately controlling two or more producing zones in an oil or gas well. The location of the piston relative to the cylinder must be stroked to a precise position. The SCRAMS tool an electronic position sensor device is used to determine the position of the actuator. Electronic devices often fail in such service due to the severe ambient conditions. It is desirable, therefore, to have an alternative means to determine or control the stroke of the actuator assembly via the hydraulic fluid control lines, outside of the well.
The volume of hydraulic fluid used to actuate or vented from the actuator assembly can in principle be used to determine the position of the piston relative to the cylinder. In use, the actuator assembly is controlled from a remote surface facility through the first and second elastic hydraulic lines, such as thermoplastic lines, which, because of their great length and material, are elastic and therefore the elastic volumetric changes in the actuating line during operation make volumes measured at the surface unreliable.
SUMMARY OF THE INVENTION
The present invention is directed to a stroke control tool for controlling the position of a subterranean well hydraulically actuated double acting piston and cylinder actuator assembly so as to allow the correct positioning of the actuator assembly following a failure of the assembly position sensor.
Still a further object is the provision of means to fix the actuator assembly position following the failure of one of the two hydraulic lines connected to and actuating the assembly.
Still a further object of the present invention is the provision of a stroke control tool comprising a hydraulic fluid measuring means positioned adjacent the well and connected to at least one of the first and second hydraulic lines for receiving hydraulic fluid. The measuring means is connected to the actuating assembly by relatively inelastic hydraulic lines whereby the volume of fluid communicating between the measuring means and the piston and cylinder actuator assembly can be accurately measured by the measuring means for determining the position of the actuator assembly.
Still another object of the present invention is wherein the measuring means includes another piston and cylinder assembly having a predetermined hydraulic fluid volume. In one embodiment the assembly is a plurality of piston and cylinder assemblies connected in parallel and each having a predetermined hydraulic fluid volume. In addition, valve means are connected to each of the plurality of assemblies for allowing the discharge or admission of hydraulic fluid separately to each of the plurality of assemblies. The plurality of assemblies may be connected in only one of the first and second hydraulic lines.
Yet a further object of the present invention is the provision of a lock-in position valve connected in at least one of the first and second hydraulic lines to hydraulically lock the actuator assembly in position in the event of a leak in one of the first and second hydraulic lines.
Yet a further object of the present invention is wherein the stroke control valve in another embodiment includes a piston and cylinder assembly with cross-over valve means between the first and second hydraulic lines for actuating the second assembly a plurality of times for providing a plurality of predetermined outputs to the actuator assembly.
A further object of the present invention is wherein the stroke control tool in another embodiment includes a piston and cylinder assembly having a position indicator for measuring the displacement of hydraulic fluid from the assembly to the actuator assembly.
Still a further object is the provision of a further embodiment of the present invention wherein the measuring means comprises a fluid flow meter for accurately measuring the flow of fluid to and from the actuator assembly for providing a precise position measurement.
Other and further objects, features and advantages will be apparent from the following description of presently preferred embodiments of the invention, given for the purpose of disclosure, and taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 2032185 (1936-02-01), Sciaky
patent: 2456869 (1948-12-01), Fowler
patent: 2740258 (1956-04-01), Weber
patent: 2927432 (1960-03-01), Parry
patent: 3548594 (1970-12-01), Ceppi
patent: 4726190 (1988-02-01), Van Marcke
patent: 5617604 (1997-04-01), Erich
patent: 5957207 (1999-09-01), Schnatzmeyer
patent: 6125938 (2000-10-01), Garcia-Soule et al.
Agip Oil US L.L.C.
Fulbright & Jaworski
Ryznic John E.
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