Cleaning and liquid contact with solids – Processes – Hollow work – internal surface treatment
Reexamination Certificate
2002-01-30
2003-09-09
Gulakowski, Randy (Department: 1746)
Cleaning and liquid contact with solids
Processes
Hollow work, internal surface treatment
C134S022120, C134S024000, C134S113000, C134S16800C
Reexamination Certificate
active
06615848
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
BACKGROUND OF THE INVENTION
The invention relates generally to apparatus and methods used for removing material from inside a conduit. More particularly, the present invention relates to a system capable of monitoring and removing material built-up on the inside surface of, or disposed within, a conduit. Still more particularly, the present invention relates to a tubing conveyed tool used to clean and caliper a flowline, pipeline, or well tubing.
Undesirable materials that build-up, or otherwise collect, on the inside walls of conduits, such as well tubing, injection lines, pipelines, flowlines, boiler tubes, heat exchangers and water lines, are known to restrict or interfere with the desired movement of fluids and equipment through the conduits. As a result, in many cases, the conduit becomes useless, or inoperable for its intended purpose. Conduits used to transport hydrocarbons, or in other oilfield applications, are particularly susceptible to the deposit of undesirable, obstructive materials such as barium sulfate, strontium sulfate, calcium sulfate, calcium carbonate, iron sulfide, other scale precipitates (such as silicates, sulfates, sulfides, fluorides, carbonates), cement corrosion products, deteriorated conduit lining, and dehydrated material (such as drilling fluid).
Current techniques for cleaning conduits used in hydrocarbon or oilfield applications include tubing conveyed cleaning methods and pipeline pigging. Tubing conveyed cleaning methods typically involve running into a conduit a cleaning device disposed on a drill string, where the drill string may be standard drill pipe or coiled tubing. Tubing conveyed cleaning devices have included those that use mechanical means, such as cutting mills, bits, or reamers, and others that use pressurized jets, possibly containing abrasives, to clean deposits from the inside of a conduit.
Various tubing conveyed techniques for conduit cleaning involve the use of a mill or bit to remove obstructive material from conduits. The mill or bit is lowered into a conduit by a string of pipe or tubing and rotated to effectively cut any deposits from the inside of the conduit. In many applications, the mills or bits have a short useful life due to damage from contact between the mills and bits and commonly occurring hard, dense, obstructive materials. Therefore, mills or bits may have to be frequently removed from the conduit and replaced, consuming time and increasing expense. Further, rotation of the mill or bit may require additional component parts, such as a motor, bearings, and rotary seals, which are complex and costly to manufacture and operate and are also subject to failure.
These techniques are also largely ineffective at loosening and removing substantially all obstructive material without damaging the conduit. For example, the inside walls of conduits cleaned with mills or bits are highly subject to damage from contact by the mill or bit. Such contact commonly occurs when the obstructions in the conduit are unevenly dispersed, causing the mill or bit to jam or rub against, or cut into, the inside of the conduit. Further, reactive torque due to the rotation of the mill or bit can also cause it to contact the inside surface of the conduit and cause damage thereto. Such reactive torque may also accelerates deterioration to the tubing, such as coiled tubing, that carries the mill or bit.
Other tubing conveyed cleaning methods utilize jet nozzles that eject liquid or angular-shaped solid particles in a foam or liquid transport medium. These systems typically operate in low to moderate pressure ranges and have often proven ineffective at loosening or removing commonly encountered hard, tightly bonded obstructive materials, such as barium sulfate. Higher pressure systems have been known too damage the inside surface of metal conduits as a result of the angular solids cutting, scarring, and eroding the metal. These systems lack the ability to minimize or control the amount of damage that occurs to the metal conduit; therefore, their use is not entirely satisfactory for many applications.
Tubing conveyed systems also may not be preferred in systems having long horizontal runs because the weight of a steel tubing string may hinder the travel of the cleaning device. The weight of a steel tubing string may cause the string to rest on the inside of the tubing, creating a resistance to moving the tubing relative to the conduit. A steel tubing string may also not be flexible enough to be inserted into a conduit string having high angle bends or other tortuous pathways.
Pipeline pigging is also well known in the art and involves pumping a “pig” through a pipeline. A pig is inserted into a conduit and forms at least a partial seal against the conduit wall so that the pig can be pumped through the pipeline using pressurized fluid. The pig scrapes deposits from the wall as it moves through the conduit. Once the pig reaches the end of a section to be cleaned, it is either removed from the conduit or pumped back to the starting position. Typically, special equipment and installations must be provided to allow access to and from the conduit for the pig at one or more locations on the conduit, which increases capital equipment costs. Pipeline pigging may also be undesirable in applications having heavy deposits, which may prohibit the movement of a pig, or where running and retrieval of a pig is difficult, such as in deep water or harsh environments. Additionally, most prior art pigs are simply pumped through the conduit with no provisions for control or monitoring of the progress of the pig or the status of the conduit bore from the surface.
Thus, there remains a need for a system for loosening and removing undesirable materials built-up, or otherwise collected, on the inside surface of conduits, that allows for remote control and monitoring of the cleaning process. The preferred system is simple, cost-effective, and easy to manufacture and operate. Ideally, the system can utilize and interface with existing equipment. Especially well received would be a system that can quickly remove all, or substantially all, of the deposited materials. Further, it would be beneficial for the system to be capable of recirculating or reusing its cleaning mixture or the constituents of the cleaning mixture.
SUMMARY OF THE PREFERRED EMBODIMENTS
The preferred embodiments provide a system and apparatus for loosening and removing undesirable deposits from the inside surface of conduits while overcoming at least some of the shortcomings of the prior art. The present system does not cause substantial or undesirable damage to the conduit and is simple, cost-effective and easy to manufacture and operate. The present system can utilize and interface with existing equipment.
One preferred embodiment comprises a powered tool that can be passed through a pipe or other conduit for the removal of solids deposited on the inner wall thereof. The tool includes equipment for advancing the tool, measuring the amount of deposited solids, and removing the solids. The tool is mounted to a string of tubing that is preferably nearly neutrally buoyant, or substantially neutrally buoyant, flexible, and is adapted to allow hydraulic and electric communication between the tool and a control location.
One preferred embodiment of an apparatus for advancing the tool includes a selectively expandable body disposed on the outside of the tool and a valve that controls the flow of fluid through the tubing string. In an expanded position, the expandable body contacts the interior wall of the conduit, including any deposits located thereon, and creates at least a partial seal against the wall. In a first position, the valve directs fluid from the tubing string to a location upstream of the tool to create a pressure differential across the expandable body that forces the tool down the conduit. In a second position, the valve directs fluid from the tubing string
Chaudhry David
Gulakowski Randy
Halliburton Energy Service,s Inc.
P.C. Conley Rose
LandOfFree
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