| Patent application number | Description | Published |
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| 20080217059 | TRACTOR WITH IMPROVED VALVE SYSTEM - A hydraulically powered tractor includes an elongated body, two gripper assemblies, at least one pair of aft and forward propulsion cylinders and pistons, and a valve system. The valve system comprises an inlet control valve, a two-position propulsion control valve, a two-position gripper control valve, two cycle valves, and two pressure reduction valves. The inlet control valve spool includes a hydraulically controlled deactivation cam that locks the valve in a closed position, rendering the tractor non-operational. The propulsion control valve is piloted on both ends by fluid pressure in the gripper assemblies. The propulsion control valve controls the distribution of operating fluid to and from the propulsion cylinders, such that one cylinder performs a power stroke while the other cylinder performs a reset stroke. Each end of the gripper control valve is piloted by a source of high-pressure fluid selectively admitted by one of the cycle valves. The gripper control valve controls the distribution of operating fluid to and from the gripper assemblies. The cycle valves are spring-biased and piloted by fluid pressure in the propulsion cylinders, so that the gripper control valve shifts only after the cylinders complete their strokes. The pressure reduction valves limit the pressure within the gripper assemblies. These valves are spring-biased and piloted by the pressure of fluid flowing into the gripper assemblies. Some or all of the valves include centering grooves on the landings of the spools, which reduce leakage and produce more efficient operation. The propulsion control and gripper control valves include spring-assisted detents to prevent inadvertent shifting. | 09-11-2008 |
| 20080308318 | ELECTRICALLY POWERED TRACTOR - An electrically powered and controlled tractor system includes one or more electric gripper assemblies and one or more electric power train assemblies. Power and control signals for the gripper assemblies and power train assemblies can be delivered from a ground surface via a wireline. The gripper assembly employs a motor-activated lead screw and nut combination to expand passage-gripping elements, preferably by pushing the gripping elements radially outward from locations between opposing ends of the gripping elements. A failsafe mechanism can retract the gripping elements during a power interruption. The power train assembly employs a motor-activated lead screw and nut combination to expand and contract two ore more telescoping members. The tractor system can include multiple tractor units that each includes one gripper assembly and one power train assembly. A tractor can include one power train assembly and two gripper assemblies. | 12-18-2008 |
| 20100018695 | GRIPPER ASSEMBLY FOR DOWNHOLE TOOLS - A gripper assembly for anchoring a tool within a downhole passage and for possibly assisting movement of the tool within the passage. The gripper assembly includes an elongated mandrel and flexible toes that can be radially displaced to grip onto the surface of the passage. The toes are displaced by the interaction of a driver slidable on the mandrel and a driver interaction element on the toes. In one embodiment, the toes are displaced by the interaction of rollers and ramps that are longitudinally movable with respect to one another. In another embodiment, the toes are displaced by the interaction of toggles that rotate with respect to the toes. | 01-28-2010 |
| 20100108387 | TRACTOR WITH IMPROVED VALVE SYSTEM - A hydraulically powered tractor includes an elongated body, two gripper assemblies, at least one pair of aft and forward propulsion cylinders and pistons, and a valve system. The valve system comprises an inlet control valve, a two-position propulsion control valve, a two-position gripper control valve, two cycle valves, and two pressure reduction valves. The inlet control valve spool includes a hydraulically controlled deactivation cam that locks the valve in a closed position, rendering the tractor non-operational. The propulsion control valve is piloted on both ends by fluid pressure in the gripper assemblies. The propulsion control valve controls the distribution of operating fluid to and from the propulsion cylinders, such that one cylinder performs a power stroke while the other cylinder performs a reset stroke. Each end of the gripper control valve is piloted by a source of high-pressure fluid selectively admitted by one of the cycle valves. The gripper control valve controls the distribution of operating fluid to and from the gripper assemblies. The cycle valves are spring-biased and piloted by fluid pressure in the propulsion cylinders, so that the gripper control valve shifts only after the cylinders complete their strokes. The pressure reduction valves limit the pressure within the gripper assemblies. These valves are spring-biased and piloted by the pressure of fluid flowing into the gripper assemblies. Some or all of the valves include centering grooves on the landings of the spools, which reduce leakage and produce more efficient operation. The propulsion control and gripper control valves include spring-assisted detents to prevent inadvertent shifting. | 05-06-2010 |
| 20110017516 | NON-ROTATING BUOYANCY MODULES FOR SUB-SEA CONDUITS - A buoyancy module assembly reduces the effective weight of a sub-sea conduit used in a deep-water wellbore drilling installation. The assembly includes a buoyant sleeve positioned around the conduit between upper and lower stop collar assemblies. The sleeve contains buoyant material forming most of its cross-section, with cross sectional segments thereof each encapsulated in a non-porous resinous material that forms an outer jacket around each segment. In one embodiment, a non-rotating generally circular inside diameter of the sleeve is formed by the thin layer of jacket material bonded directly to an interior reinforcing cage. A narrow gap is formed between the ID of the non-rotating sleeve and the OD of the conduit. The collar assemblies comprise an inner collar rigidly affixed to the conduit and contained within a larger diameter outer shell adapted for rotation relative to the fixed inner collar. | 01-27-2011 |
| 20110067926 | ELECTRICALLY POWERED TRACTOR - An electrically powered and controlled tractor system includes one or more electric gripper assemblies and one or more electric power train assemblies. Power and control signals for the gripper assemblies and power train assemblies can be delivered from a ground surface via a wireline. The gripper assembly employs a motor-activated lead screw and nut combination to expand passage-gripping elements, preferably by pushing the gripping elements radially outward from locations between opposing ends of the gripping elements. A failsafe mechanism can retract the gripping elements during a power interruption. The power train assembly employs a motor-activated lead screw and nut combination to expand and contract two or more telescoping members. The tractor system can include multiple tractor units that each includes one gripper assembly and one power train assembly. A tractor can include one power train assembly and two gripper assemblies. | 03-24-2011 |
| 20110114307 | OPEN HOLE NON-ROTATING SLEEVE AND ASSEMBLY - A non-rotating downhole sleeve adapted for open hole drilling and/or casing centralization. The sleeve includes a tubular body made of hard plastic with integrally formed helical blades positioned around its outer surface and an inner surface configuration which allows drilling fluid circulation to form a non-rotating fluid bearing between the sleeve and the drill pipe or casing. The helical blades reduce sliding and rotating torque while drilling, with minimal obstruction to drilling fluid passing through the borehole between the blades. In one embodiment, improvements are provided during casing exit when drilling in open hole environments. In another embodiment, improvements are provided in the sleeve's resistance to compressive loading. | 05-19-2011 |
| 20110114338 | NON-ROTATING CASING CENTRALIZER - A non-rotating downhole sleeve adapted for casing centralization in a borehole. The sleeve includes a tubular body made of hard plastic with integrally formed helical blades positioned around its outer surface and an inner surface which allows drilling fluid to circulate to form a non-rotating fluid bearing between the sleeve and the casing. The tubular sleeve comprises a continuous non-hinged wall structure for surrounding the casing. The non-rotating centralizer sleeve reduces sliding and rotating torque at the surface while drilling the casing, for example, with minimal obstruction to drilling fluid passing between the casing and the surrounding borehole. | 05-19-2011 |
