Setting tool and related method

Abstract: There is disclosed a setting tool for setting of any of a variety of down-hole devices used in petroleum/gas producing wells. A known setting tool employs an explosive charge. A disadvantage of this tool is that due to safety considerations, when such tools are in use, radio silence must be maintained on the drilling rig. Another known setting tool employs hydraulic forces. A number of problems exist with known tools. The present invention, therefore, provides a setting tool (5a, 5b) comprising a timer (35a, 35b), control means responsive to the timer, and setting means responsive to the action of the control means for setting a down-hole device in place at a desired location within a well-bore wherein, in use, the timer is set to a predetermined period of time, the tool in association with the device is conveniently inserted into the well-bore to the desired location, and after the predetermined period has elapsed the timer causes the control means to actuate so causing the setting means to set the device in place in the well-bore.

Description: This invention relates to a setting tool for use in the setting of any of a variety of down-hole devices such as, though not exclusively, bridge plugs, cement retainers and permanent packers used in petroleum/gas producing wells. One type of known setting tool employs an explosive (power) charge. In use, the tool is primed with a charge and lowered down the well-bore to a desired location by wireline. An electrical signal controlled by an above surface rheostat is then sent down the wireline in order to detonate the explosive charge so actuating the tool and setting the device. A major disadvantage of this type of setting tool is that due to safety considerations, when such tools are in use, radio silence must be maintained on the drilling rig. This is because the detonators used in such environments are classed as electro-explosive devices requiring special precautions to be taken whilst being handled. These precautions involve the elimination of stray electric potential differences whilst the tool is being assembled at surface. Such potential differences can originate from sources such as radio frequency radiation, electric welding, or lightning storms. Another type of known setting tool employs hydraulic forces. In use, the tool and device are run down the well-bore on drill-pipe to a desired location. Hydraulic forces are then exerted within the drill-pipe via a hydraulic fluid by a pump or pumps located at the surface. The hydraulic forces thereby actuate the setting tool so setting the device. A number of problems exist with this type of setting tool. For example, since the tool is run-in on drill-pipe the task is time consuming and expensive - the task typically might take one and a half days to complete. Further, the use of drill-pipe makes it difficult to accurately locate the tool in the bore-hole. US 3 960 215 (CHEVRON) discloses a wireline device for use in performing sequentially timed operations in a well comprising operating means for performing sequential operations in a well and sequencing timer actuating means for operating said operating means, said sequencing timer actuating means comprising a cylinder, an orifice in said cylinder, a noncompressible liquid in said cylinder upstream of said orifice, means for applying pressure on said liquid upstream of said orifice to move said liquid through said orifice and stem means connected to said operating means to operate said operating means on movement of said stem means, said stem means being moved in response to flow through said orifice. It is, therefore, an object of the present invention to obviate or mitigate the aforementioned disadvantage in the prior art. According to a first aspect of the present invention there is provided a setting tool comprising a timer, control means responsive to the timer, and setting means responsive to the action of the control means for setting a down-hole device in place at a desired location within a well-bore wherein, in use, the timer is set to a predetermined period of time, the tool in association with the device is conveniently inserted into the well-bore to the desired location, and after the predetermined period has elapsed the timer causes the control means to actuate so causing the setting means to set the device in place in the well-bore, characterised in that hydrostatic pressure within the well-bore at the desired location is employed to set the device, and the control means comprises an electric motor responsive to the timer and an actuator responsive to the motor, the electrical power source also supplying electrical power to the electric motor. Preferably, the timer is electronic, the tool providing an electrical power source which supplies electrical power to the timer. The timer is, therefore, not affected by radio frequencies or high voltage interference. Preferably also, the electric power source also supplies power to the electric motor. Further, the response of the actuator may cause one or more ports communicating through a side wall of the tool to open thereby allowing hydrostatic pressure to be applied to the setting means contained substantially within the tool. The setting means may comprise a sealed chamber filled with a low viscosity fluid and provide a floating piston a first surface of which is acted upon at the start of a setting sequence by the hydrostatic pressure, in use, and a second surface of which forms a first end of the sealed chamber, a second end of the chamber being formed by a first surface of another piston. The setting means may further comprise one or more hydrostatic chambers the volume of which is reduced by movement of the floating piston due to the action of the hydrostatic pressure, in use. Speed of setting may be controlled by means of a choke which is situated between the second surface of the floating piston and the first surface of another piston in the upper of the hydrostatic chambers. Selection of the number of hydrostatic chamber(s) can, therefore, by used to control the minimum hydrostatic pressure required to activate the setting means. The tool and device may be conveniently lowered into the well-bore to a required location by means of wireline. The wireline may be approximately 4.72mm to 2.34mm (0.1875" to 0.092") in diameter. According to a second aspect of the present invention there is provided a down-hole device integrally incorporating a setting device according to the first aspect of the invention. According to a third aspect of the present invention there is provided a method of setting a down-hole device in place at a desired location within a well-bore comprising inserting the device into the well-bore in association with a setting tool (5a) to the desired location, the setting tool comprising a timer (35a), control means responsive to the timer, and setting means responsive to the action of the control means, the timer having been set to a predetermined period of time after which predetermined period having elapsed the timer causes the control means to act so causing the setting means to set the device in place in the well-bore, characterised in that hydrostatic pressure within the well-bore at the desired location is employed to set the device, and the control means comprises an electric motor (40a) responsive to the timer and an actuator (45a, 50a) responsive to the electric motor. An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, which is Fig 1 a partial cross-sectional side view of a first embodiment of a setting tool according to the present invention in a running-in position. Referring to Fig 1, there is illustrated an embodiment of a retrievable setting tool, generally designated 5a. At a first end 10a of the tool 5a, which end comprises the uppermost end, in use, there is provided a fishing neck 15a (which carries a pressure port and actuating piston) a lower end of which is connected to an upper end of a first housing 20a. A lower end of the first housing 20a is connected to a second housing 25a via a connecting cylindrical body 26a. Within the first housing 20a there is located a battery pack 30a, which preferably supplies a 12-15v DC voltage, an electronic timer 35a, which is supplied with electrical power from the battery pack 30a, and a retracting spring 31a. An output of the timer 35a is further connected to an input of an electric motor 40a which is located within the second housing 26a. A mechanical output shaft or lead screw 45a of the motor 40a is connected to a first piston 50a which is movable by means of the motor 40a between a first lower and a second upper position. An outer surface of the first piston 50a is sealably and movably engaged with an inner surface of the second housing 25a by means of first and second seals 55a. As can be seen from Fig 1 a plurality of first ports 60a extend through the side wall of the housing 25a. When the piston 50a is in the lower position the ports 60a are effectively closed, while when the piston 50a is in the upper position the ports 60a are effectively open, opening a path(s) from outside the tool 5a to inside a lower end of the second housing 25a. The lower end of the second housing 25a is sealably connected to an upper end of a setting means, generally designated 65a. The setting means 65a comprises a cylindrical body 70a, within which there is provided a second, floating piston 83a. Connected to a lower-facing innermost surface of the cylinder 70a is a first cylindrical outer shell portion 85a which is connected via a first connector sub 90a to a second cylindrical outer shell portion 95a which is similarly connected via a connector sub 100a to a lower cylinder 105a. Contained in the upper end of portion 85a is a so-called controlled orifice bean 84a. Provided within the lower cylinder 105a is a third piston 115a, an outermost edge of which has a seal 124a allowing sealed movement of the edge along an innermost edge of the cylinder 105a. It can, therefore, be seen that the second, floating piston 83a and the third piston 115a comprise the upper and lower limits of a sealed chamber 120a which is filled with a low viscosity fluid. Provided within the sealed chamber 120a are first, second and subsequent sealed hydrostatic chambers 125a, 130a etc. The chamber 125a is defined by a portion of an innermost surface of the first cylindrical outer shell portion 85a, an innermost surface of the first connector sub 90a, an outerfacing surface of a first mandrel 135a carried by piston 140a and an outwardly/downwardly facing surface of a fourth piston 140a. The fourth piston 140a is moveable downwardly within the sealed chamber 120a - so as to reduce the volume of the first hydrostatic chamber 125a - in response to hydrostatic pressure acting on the second piston 83a. The extend of movement is limited when an upperfacing surface of the portion 95a abuts a lowerfacing surface of the fourth piston 140a. Likewise the second hydrostatic chamber 130a is defined by a portion of an innermost surface of the second cylindrical outer shell portion 95a, an innermost surface of the third cylinder 105a (or subsequent cylinder identical to 95a), an outerfacing surface of a mandrel carried by piston 150a and an outwardly/downwardly facing surface of a fifth piston 150a. An upperfacing surface of the fifth piston 150a further abuts a lowerfacing surface of a lowermost end of the first mandrel 135a. Also, an upperfacing surface of the third piston 115a abuts a lowerfacing surface of the fifth piston 150a (or subsequent pistons identical to 150a). Pistons 140a, 150a and any subsequent pistons have a drilled longitudinal passage from an upper surface of a piston, to a lower end thereof. These passages are designated 141a and 151a respectively on Fig 1. The fourth and fifth (and subsequent) piston rods 140a and 150a have first, second and subsequent ports 155a and 160a extending radially therethrough at or near the lower ends thereof. As can be seen from Fig 1, the third piston 115a with its piston mandrel 116a is T-shape in cross-section, and a third hydrostatic chamber 165a is defined by the inside of the T-shape, an inner portion of the lower cylinder 105a and an upperfacing surface of a cylinder head 170a which closes the lower cylinder 105a. The piston mandrel 116a extends through a central aperture in the cylinder head 170a, a cross-link 175a being provided near to a lowermost end of the third piston 115a. An outer edge of the cross-link 175a engages a cross link sleeve 180a. These are held together by a link retaining ring 185a. The cross-link sleeve 180a rides over the setting mandrel 190a. In use, the timer 35a is set to a predetermined period, for example, 2 hours. The tool 5a is then lowered down a bore-hole by slick-line or piano wire (attached to a sucker rod connection at the first upper end 10a of the fishing neck 15a) to the required depth. A device (not shown) is retained on the lower end of the tool 5a by means of a shear ring (not shown) as is known in the art, the setting mandrel 190a extending within the device. After the predetermined period has elapsed, the timer 35a activates the motor 40a, the lead screw of which retracts the first piston 50a to its second position thereby opening the ports 60a. Hydrostatic pressure is therefore applied to the second piston 83a causing downward movement of the fourth and fifth and subsequent pistons 140a, 150a etc and consequential downward movement of the third piston 115a, cross-link 175a and cross-link sleeve 180a, thereby setting the device by the downward movement of the link sleeve 180a. The shear ring shears allowing retrieval of the tool 5a. The embodiment of the present invention hereinbefore described is given by way of example only and is not meant to limit the scope of the invention as defined by the appended claims in any way.

Claims: A setting tool (5a) comprising a timer (35a), control means responsive to the timer, and setting means responsive to the action of the control means for setting a down-hole device in place at a desired location within a well-bore wherein, in use, the timer is set to a predetermined period of time, the tool in association with the device is inserted into the well-bore to the desired location, and after the predetermined period has elapsed the timer causes the control means to actuate so causing the setting means to set the device in place in the well-bore, characterised in that hydrostatic pressure within the well-bore at the desired location is employed to set the device, and the control means comprises an electric motor (40a) responsive to the timer and an actuator (45a, 50a) responsive to the electric motor. A setting tool as claimed in claim 1, wherein the timer is electronic, the tool providing an electrical power source (30a) which supplies electrical power to the timer. A setting tool as claimed in claim 2, wherein the electrical power source also supplies power to the electric motor. A setting tool as claimed in any of claims 1 to 3, wherein the response of the actuator causes one or more ports (60a) communicating through a side wall of the tool to open thereby allowing hydrostatic pressure to be applied to the setting means contained substantially within the tool. A setting tool as claimed in any preceding claims, wherein the setting means comprises a sealed chamber (120a) filled with a low viscosity fluid and provides a floating piston (83a) a first surface of which is acted upon by the hydrostatic pressure, in use, and a second surface of which forms a first end of the sealed chamber, a second end of the chamber being formed by a first surface of another piston (115a). A setting tool as claimed in claim 5, wherein the setting means further comprises one or more hydrostatic chambers (125a, 130a, 165a) the volume of which is reduced by movement of the floating piston due to the action of the hydrostatic pressure, in use. A setting tool as claimed in any preceding claim, wherein the tool and device can be conveniently lowered into the well-bore to a required location by means of wireline. A setting tool as claimed in claim 9, wherein the wireline is approximately 4.76mm to 2.34mm (0.1875" to 0.092") in diameter. A down-hole device integrally incorporating a setting tool according to any of claims 1 to 8. A method of setting a down-hole device in place at a desired location within a well-bore comprising inserting the device into the well-bore in association with a setting tool (5a) to the desired location, the setting tool comprising a timer (35a), control means responsive to the timer, and setting means responsive to the action of the control means, the timer having been set to a predetermined period of time after which predetermined period having elapsed the timer causes the control means to act so causing the setting means to set the device in place in the well-bore, characterised in that hydrostatic pressure within the well-bore at the desired location is employed to set the device, and the control means comprises an electric motor (40a) responsive to the timer and an actuator (45a, 50a) responsive to the electric motor.

Inventors: LITTLEFORD SYDNEY JOSEPH, LITTLEFORD, SYDNEY JOSEPH
Applicants: PETROLEUM ENG SERVICES, PETROLEUM ENGINEERING SERVICES LIMITED
Application year: 1993
Main classification: E21B41
IPC codes: E21B41, E21B23