US20020023749A1 - Casing centrliser - Google Patents
Casing centrliser Download PDFInfo
- Publication number
- US20020023749A1 US20020023749A1 US09/378,858 US37885899A US2002023749A1 US 20020023749 A1 US20020023749 A1 US 20020023749A1 US 37885899 A US37885899 A US 37885899A US 2002023749 A1 US2002023749 A1 US 2002023749A1
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- US
- United States
- Prior art keywords
- centraliser
- casing
- blades
- annular body
- casing centraliser
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Links
- 239000000463 material Substances 0.000 claims abstract description 32
- 239000004033 plastic Substances 0.000 claims abstract description 17
- 229920003023 plastic Polymers 0.000 claims abstract description 17
- 229920001971 elastomer Polymers 0.000 claims description 22
- 239000005060 rubber Substances 0.000 claims description 22
- 150000001875 compounds Chemical class 0.000 claims description 12
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 12
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 12
- -1 polytetrafluoroethylene Polymers 0.000 claims description 11
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 10
- 239000004696 Poly ether ether ketone Substances 0.000 claims description 7
- 229910052799 carbon Inorganic materials 0.000 claims description 7
- 229920002530 polyetherether ketone Polymers 0.000 claims description 7
- 239000000945 filler Substances 0.000 claims description 5
- 239000002033 PVDF binder Substances 0.000 claims description 4
- 239000004952 Polyamide Substances 0.000 claims description 4
- 239000004698 Polyethylene Substances 0.000 claims description 4
- 239000004954 Polyphthalamide Substances 0.000 claims description 4
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims description 4
- 229910052751 metal Inorganic materials 0.000 claims description 4
- 239000002184 metal Substances 0.000 claims description 4
- 229920001568 phenolic resin Polymers 0.000 claims description 4
- 239000005011 phenolic resin Substances 0.000 claims description 4
- 229920002492 poly(sulfone) Polymers 0.000 claims description 4
- 229920002647 polyamide Polymers 0.000 claims description 4
- 229920000573 polyethylene Polymers 0.000 claims description 4
- 229920006375 polyphtalamide Polymers 0.000 claims description 4
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 4
- 229920001169 thermoplastic Polymers 0.000 claims description 4
- 229920002725 thermoplastic elastomer Polymers 0.000 claims description 4
- 229920006230 thermoplastic polyester resin Polymers 0.000 claims description 4
- 239000004416 thermosoftening plastic Substances 0.000 claims description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 3
- 239000012530 fluid Substances 0.000 claims description 3
- 239000011521 glass Substances 0.000 claims description 3
- 239000010439 graphite Substances 0.000 claims description 3
- 229910002804 graphite Inorganic materials 0.000 claims description 3
- CWQXQMHSOZUFJS-UHFFFAOYSA-N molybdenum disulfide Chemical compound S=[Mo]=S CWQXQMHSOZUFJS-UHFFFAOYSA-N 0.000 claims description 3
- 239000003921 oil Substances 0.000 claims description 3
- 229920001652 poly(etherketoneketone) Polymers 0.000 claims description 3
- 229920001707 polybutylene terephthalate Polymers 0.000 claims description 3
- 229910052710 silicon Inorganic materials 0.000 claims description 3
- 239000010703 silicon Substances 0.000 claims description 3
- 239000001993 wax Substances 0.000 claims description 3
- 238000009826 distribution Methods 0.000 claims description 2
- 239000013536 elastomeric material Substances 0.000 claims description 2
- 230000002093 peripheral effect Effects 0.000 claims description 2
- 238000010276 construction Methods 0.000 claims 1
- 239000004697 Polyetherimide Substances 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 229920001601 polyetherimide Polymers 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 229920001187 thermosetting polymer Chemical class 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 2
- 229920000265 Polyparaphenylene Polymers 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000000565 sealant Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
- E21B17/10—Wear protectors; Centralising devices, e.g. stabilisers
- E21B17/1057—Centralising devices with rollers or with a relatively rotating sleeve
- E21B17/1064—Pipes or rods with a relatively rotating sleeve
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
- E21B17/10—Wear protectors; Centralising devices, e.g. stabilisers
- E21B17/1042—Elastomer protector or centering means
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
- E21B17/22—Rods or pipes with helical structure
Definitions
- the invention relates to a casing centraliser.
- This application is a Continuation-In-Part of PCT/GB98/00554 to which filing details hare not yet been assigned by the USPTO.
- one of the procedures commonly employed in readying the well for production comprises installing hollow tubular casing in the well to line the borehole.
- the space between the exterior of the casing and the sides of the borehole are filled with cement, which acts as a sealant and provides mechanical support for the casing.
- cement acts as a sealant and provides mechanical support for the casing.
- the annular body being formed from at least one material selected from the group consisting of plastic material, elastomeric material and rubber material, the substantially cylindrical bore being a clearance fit around the tubular casing to be centralised by the centraliser.
- a casing centraliser assembly comprising tubular casing and a centraliser as defined above.
- the plastic, elastomeric and/or rubber material may comprise polytetrafluoroethylene (PTFE), polyetheretherketone, carbon reinforced polyetheretherketone, polyphthalamide, polyvinylidene fluoride, polyphenylylene sulphide, polyetherimide, polyethylene, polysulphone, polyethersulphone, polybutyleneterephthalate, polyetherketoneketone, polyamides, rubber & rubber compounds, phenolic resins or compounds, thermosetting plastics, thermoplastic elastomers, thermoplastic compounds or thermoplastic polyester resins.
- PTFE polytetrafluoroethylene
- polyetheretherketone carbon reinforced polyetheretherketone
- polyphthalamide polyvinylidene fluoride
- polyphenylylene sulphide polyetherimide
- polyethylene polyethylene
- polysulphone polyethersulphone
- polybutyleneterephthalate polyetherketoneketone
- polyamides polyamides
- rubber & rubber compounds phenolic resins or compounds
- the plastic, elastomeric or rubber material may contain a filler material, such as glass, carbon, PTFE, silicon, molybdenum disulphide, graphite, oil or wax, or any combination of these materials.
- a filler material such as glass, carbon, PTFE, silicon, molybdenum disulphide, graphite, oil or wax, or any combination of these materials.
- the annular body may be manufactured from and consist of the plastic, elastomeric and/or rubber material.
- the annular body may comprise a combination of the plastic, elastomeric and/or rubber material and another material such as a metal.
- the annular body may comprise a metal skeleton or other structures coated, or partially coated, with the plastic, elastomeric or rubber material.
- the annular body may comprise a combination of different plastic, elastomeric and/or rubber materials.
- the annular body may be formed in one or more sections which may be assembled around the tubular to be centralised by the centraliser.
- the annular body is divided into 2 sections along its axis so that each sector forms a “half shell” arrangement.
- the concave surface of one section can be fitted direct against one side of the outer surface of the tubular and connected to another section similarly positioned against the opposite side of the tubular.
- the 2 sections can then be connected around the tubular to make up the centraliser so that it does not need to be offered up to the end of the tubular. This can be very useful in coil tubing applications.
- the sections can be hingedly attached to one another.
- the 2 sections can be separate. There can be more than 2 sections provided. It is sufficient that the sections are adapted to allow the centraliser to be placed around the tubular without needing to be threaded over an end of the tubular.
- the sections are preferably held together by fixings and/or hinges.
- Preferred fixings include bolts but catches and locks can also be used.
- the centraliser further comprises a peripheral array of a plurality of longitudinally extending blades circumferentially distributed around said body to define a flow path between each circumferentially adjacent pair of said blades, each said flow path providing a fluid flow path between longitudinally opposite ends of said centraliser, each said blade having a radially outer edge providing a well bore-contacting surface.
- Said centraliser is preferably free of any means tightly gripping a casing when said centraliser is installed thereon, whereby said centraliser and said casing are mutually rotatable.
- Said blades are preferably mutually substantially equidistantly distributed around said body.
- Said blades preferably each extend circumferentially at least part-way around said body between longitudinally opposite ends thereof to provide a circumferential distribution of each said well bore-contacting surface.
- Each said blade preferably has a radially inner root integral with said body, each said radially inner root preferably being circumferetially wider than the respective radially outer edge.
- Said blades are preferably circumferentially wider at one end of the centraliser than at the other end, said one end preferably the lower end of the centraliser in use thereof.
- Said centraliser preferably has five of said blades.
- Longitudinally opposite ends of said blades and/or of said body may be chamfered or tapered whereby to facilitate passage of said centraliser down a well bore.
- FIG. 1 is a perspective view from above and to one side of a first example of a casing centraliser
- FIG. 2 is a plan view from above of the first example
- FIG. 3 is an underneath view of the first example
- FIGS. 4 and 5 are respectively radial (plan) and cirumferential (side) views of a blade forming part of the first example;
- FIG. 6 is a perspective view of a casing centraliser mounted on casing in a borehole
- FIG. 7 a shows a side view of a second centraliser on a tubular
- FIG. 7 b shows the same centraliser in plan view
- FIG. 7 c shows the same centraliser in exploded plan view.
- a casing centraliser 10 is a unitary annulus comprising a generally cylindrical body 12 , and an array of five equiangularly-spaced blades 14 integrally formed with the body 12 .
- a cylindrical bore 16 extends longitudinally and coaxially through the body 12 , the bore 16 having a substantially uniform diameter dimensioned to be a clearance fit around the well bore casing (not shown in FIGs. 1 to 8 ).
- Each of the blades 14 (see also FIGS. 4 and 5) not only extends between longitudinally opposite ends of the body 12 , but also extends circumferentially part-way around the periphery of the centraliser 10 .
- the skewing of the blade 14 ensures that their respective radially outer edges 18 collectively provide a circumferentially substantially uniform well bore-contacting surface for the centraliser 10 , as most particularly shown in FIGS. 2 and 3.
- Each of the blades 14 has a respective radially inner root 20 integral with the body 12 .
- the root 20 has a greater circumferential width than the outer edge 18 , ie the cross-section of each blade 14 tapers towards the well bore-contacting periphery of the centraliser 10 .
- the individual and collective shapes of the blades 14 , and of the longitudinal fluid flow passages defined between adjacent pairs of the blades 14 gives the centraliser 10 improved flow characteristics and minimises the build-up of trapped solids during use of the centraliser 10 .
- the blades 14 are shown separately from the body 12 in FIGS. 4 and 5 (and while the blades 4 could be separately formed and subsequently attached to the body 12 by any suitable means) it is preferred that the entire centraliser 10 is fabricated as a one-piece article.
- the centraliser 10 may be manufactured entirely from a plastics, elastomeric and/or rubber material.
- the centraliser may comprise a metal body coated, or partially coated, with a plastic, elastomeric and/or rubber material.
- plastic, elastomeric and/or rubber materials are polytetrafluoroethylene (PTFE), polyetheretherketone, carbon reinforced polyetheretherketone, polyphthalamide, polyvinylidene fluoride, polyphenylene sulphide, polyetherimide, polyethylene, polysulphone, polyethersulphone, polybuctyleneterephthalate, polyetherketoneketore, polyamides, rubber & rubber compounds, phenolic resins or compounds, thermosetting plastics, thermoplastic elastomers, thermoplastic compounds or thermoplastic polyester resins.
- PTFE polytetrafluoroethylene
- polyetheretherketone carbon reinforced polyetheretherketone
- polyphthalamide polyvinylidene fluoride
- polyphenylene sulphide polyetherimide
- polyethylene polyethylene
- polysulphone polyethersulphone
- polybuctyleneterephthalate polyetherketoneketore
- polyamides polyamides
- rubber & rubber compounds phenolic resins or compounds
- the plastics, elastomeric and/or rubber material may contain a filler.
- a filler examples include glass, carbon, PFTE, silicon, molybdenum disulphide, graphite, oil or wax, or any combination of these materials.
- the centraliser 10 can not only rotate freely around the casing but also move freely along the casing unless and until the centraliser collides with an obstruction, for example a protruding casing joint).
- an obstruction for example a protruding casing joint.
- FIG. 6 shows a modified for of casing centraliser 100 , fitted around hollow tubular casing 102 which is located within a well bore 104 .
- the modified centraliser 100 is essentially the same as the centraliser 10 described above, and differs principally in the dimensions and proportions of its blades 106 .
- the blades 106 are circumferentially wider at the lower end of the centraliser 100 than they are at the upper end.
- FIG. 6 also illustrates the manner in which the centraliser will hold casing out of direct contact with the well bore and centrally within the well bore, in preparation for subsequent cementing.
- FIG. 7 shows a modified plastic centraliser 110 located around a length of casing 112 .
- the centraliser 10 has blades R 1 , R 2 , R 3 and R 4 spaced around its outer surface to contact the inner surface of the wellbore and to centralise the casing 112 therein.
- the blades R extend axially along the centraliser but can alternatively extend around the outer circumference of the centraliser like the blades 106 .
- the centraliser 110 is axially divided along the midline of opposing blades R 2 and R 4 to form two shells 110 a and 110 b , so that the blades R 2 and R 4 are formed only when the opposing faces F of the half shells 110 a and 110 b are joined together.
- Half shell 110 a has two threaded sockets S in each of the faces F of R 2 and R 4 to receive bolts B protruding through the faces F of the other half shell 110 b .
- the bolts B engage in the sockets S and pull the faces F together when the centraliser 110 is made up around the casing 112 and the bolts tightened.
- the centaliser 110 can be formed from polytetrafluoroethylene (PTFE), polyetheretheketone, carbon reinforced polyetheretherketone, polyphthalamide, polyvinylidene fluoride, polyphenylylene sulphide, polyetherimide, polyethylene, polysulphone, polyethersulphone, polybutyleneterephthalate, polyetherketoneketone, polyamides, rubber & rubber compounds, phenolic resins or compounds, thermosetting plastics, thermoplastic elastomers, thermoplastic compounds or thermoplastic polyester resins.
- PTFE polytetrafluoroethylene
- polyetheretheketone carbon reinforced polyetheretherketone
- polyphthalamide polyvinylidene fluoride
- polyphenylylene sulphide polyetherimide
- polyethylene polyethylene
- polysulphone polyethersulphone
- polybutyleneterephthalate polyetherketoneketone
- polyamides polyamides
- rubber & rubber compounds phenolic resins or compounds
- thermosetting plastics
- the centraliser 110 is useful with coil tubing applications, but may also be used for casing and screens to afford protection from acids and other harmful chemicals downhole.
- centralisers can be employed on the inner casing to hold it out of direct contact with the outer casing.
- Advantages of the invention are that the use of a plastics, elastomeric and/or rubber material for the centraliser helps to provide chemical resistance, such as resistance to corrosion from acid. Other advantages are that the materials are generally non sparking and that certain materials, for example PTFE, have superior bearing properties.
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- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
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Abstract
Description
- The invention relates to a casing centraliser. This application is a Continuation-In-Part of PCT/GB98/00554 to which filing details hare not yet been assigned by the USPTO.
- When a well has been drilled for the eventual production of hydrocarbons, one of the procedures commonly employed in readying the well for production comprises installing hollow tubular casing in the well to line the borehole. The space between the exterior of the casing and the sides of the borehole are filled with cement, which acts as a sealant and provides mechanical support for the casing. As it is desirable that the casing be centralized in the well bore when cemented, proposals have been made for providing the casing (prior to cementing) with externally mounted centralisers to hold the casing away from the well bore and towards the centre of the bore.
- longitudinally therethrough, the annular body being formed from at least one material selected from the group consisting of plastic material, elastomeric material and rubber material, the substantially cylindrical bore being a clearance fit around the tubular casing to be centralised by the centraliser.
- In a preferred embodiment invention provides a casing centraliser assembly comprising tubular casing and a centraliser as defined above.
- Typically, the plastic, elastomeric and/or rubber material may comprise polytetrafluoroethylene (PTFE), polyetheretherketone, carbon reinforced polyetheretherketone, polyphthalamide, polyvinylidene fluoride, polyphenylylene sulphide, polyetherimide, polyethylene, polysulphone, polyethersulphone, polybutyleneterephthalate, polyetherketoneketone, polyamides, rubber & rubber compounds, phenolic resins or compounds, thermosetting plastics, thermoplastic elastomers, thermoplastic compounds or thermoplastic polyester resins.
- In one example of the invention, the plastic, elastomeric or rubber material may contain a filler material, such as glass, carbon, PTFE, silicon, molybdenum disulphide, graphite, oil or wax, or any combination of these materials.
- The annular body may be manufactured from and consist of the plastic, elastomeric and/or rubber material. However, the annular body may comprise a combination of the plastic, elastomeric and/or rubber material and another material such as a metal. For example, the annular body may comprise a metal skeleton or other structures coated, or partially coated, with the plastic, elastomeric or rubber material. In addition, or as an alternative, the annular body may comprise a combination of different plastic, elastomeric and/or rubber materials.
- The annular body may be formed in one or more sections which may be assembled around the tubular to be centralised by the centraliser. In one embodiment the annular body is divided into 2 sections along its axis so that each sector forms a “half shell” arrangement. The concave surface of one section can be fitted direct against one side of the outer surface of the tubular and connected to another section similarly positioned against the opposite side of the tubular. The 2 sections can then be connected around the tubular to make up the centraliser so that it does not need to be offered up to the end of the tubular. This can be very useful in coil tubing applications.
- The division between the sections need not be axial.
- In some embodiments the sections can be hingedly attached to one another. In others the 2 sections can be separate. There can be more than 2 sections provided. It is sufficient that the sections are adapted to allow the centraliser to be placed around the tubular without needing to be threaded over an end of the tubular.
- The sections are preferably held together by fixings and/or hinges. Preferred fixings include bolts but catches and locks can also be used.
- Preferably the centraliser further comprises a peripheral array of a plurality of longitudinally extending blades circumferentially distributed around said body to define a flow path between each circumferentially adjacent pair of said blades, each said flow path providing a fluid flow path between longitudinally opposite ends of said centraliser, each said blade having a radially outer edge providing a well bore-contacting surface.
- Said centraliser is preferably free of any means tightly gripping a casing when said centraliser is installed thereon, whereby said centraliser and said casing are mutually rotatable.
- Said blades are preferably mutually substantially equidistantly distributed around said body. Said blades preferably each extend circumferentially at least part-way around said body between longitudinally opposite ends thereof to provide a circumferential distribution of each said well bore-contacting surface. Each said blade preferably has a radially inner root integral with said body, each said radially inner root preferably being circumferetially wider than the respective radially outer edge. Said blades are preferably circumferentially wider at one end of the centraliser than at the other end, said one end preferably the lower end of the centraliser in use thereof. Said centraliser preferably has five of said blades.
- Longitudinally opposite ends of said blades and/or of said body may be chamfered or tapered whereby to facilitate passage of said centraliser down a well bore.
- Examples of a casing centraliser in accordance with the invention will now be described with reference to the accompanying drawings, in which:
- FIG. 1 is a perspective view from above and to one side of a first example of a casing centraliser;
- FIG. 2 is a plan view from above of the first example;
- FIG. 3 is an underneath view of the first example;
- FIGS. 4 and 5 are respectively radial (plan) and cirumferential (side) views of a blade forming part of the first example;
- FIG. 6 is a perspective view of a casing centraliser mounted on casing in a borehole;
- FIG. 7a shows a side view of a second centraliser on a tubular,
- FIG. 7b shows the same centraliser in plan view, and
- FIG. 7c shows the same centraliser in exploded plan view.
- Referring first to FIGS.1 to 3, a
casing centraliser 10 is a unitary annulus comprising a generallycylindrical body 12, and an array of five equiangularly-spacedblades 14 integrally formed with thebody 12. Acylindrical bore 16 extends longitudinally and coaxially through thebody 12, thebore 16 having a substantially uniform diameter dimensioned to be a clearance fit around the well bore casing (not shown in FIGs. 1 to 8). Each of the blades 14 (see also FIGS. 4 and 5) not only extends between longitudinally opposite ends of thebody 12, but also extends circumferentially part-way around the periphery of thecentraliser 10. The skewing of theblade 14 ensures that their respective radiallyouter edges 18 collectively provide a circumferentially substantially uniform well bore-contacting surface for thecentraliser 10, as most particularly shown in FIGS. 2 and 3. - Each of the
blades 14 has a respective radiallyinner root 20 integral with thebody 12. In each of theblades 14, theroot 20 has a greater circumferential width than theouter edge 18, ie the cross-section of eachblade 14 tapers towards the well bore-contacting periphery of thecentraliser 10. The individual and collective shapes of theblades 14, and of the longitudinal fluid flow passages defined between adjacent pairs of theblades 14, gives thecentraliser 10 improved flow characteristics and minimises the build-up of trapped solids during use of thecentraliser 10. - Longitudinally opposite ends of the
blades 14, and of thebody 12, are chamfered to assist in movement of thecentraliser 10 up/down a well bore. - Although the
blades 14 are shown separately from thebody 12 in FIGS. 4 and 5 (and while the blades 4 could be separately formed and subsequently attached to thebody 12 by any suitable means) it is preferred that theentire centraliser 10 is fabricated as a one-piece article. - The
centraliser 10 may be manufactured entirely from a plastics, elastomeric and/or rubber material. Alternatively, the centraliser may comprise a metal body coated, or partially coated, with a plastic, elastomeric and/or rubber material. - Examples of possible plastic, elastomeric and/or rubber materials are polytetrafluoroethylene (PTFE), polyetheretherketone, carbon reinforced polyetheretherketone, polyphthalamide, polyvinylidene fluoride, polyphenylene sulphide, polyetherimide, polyethylene, polysulphone, polyethersulphone, polybuctyleneterephthalate, polyetherketoneketore, polyamides, rubber & rubber compounds, phenolic resins or compounds, thermosetting plastics, thermoplastic elastomers, thermoplastic compounds or thermoplastic polyester resins.
- The plastics, elastomeric and/or rubber material may contain a filler. Examples of possible fillers are glass, carbon, PFTE, silicon, molybdenum disulphide, graphite, oil or wax, or any combination of these materials.
- Use of a plastic, elastomeric and/or rubber material gives a number of advantages, including:- chemical resistance, such as resistance to acid; non-sparking (ie sparks are not generated if the centraliser10 collides with steel); and, materials such, as PTFE give superior bearing properties.
- Since the
bore 16 is a clearance fit around the casing and since thebore 16 lacks any means of tightly gripping a normally dimensioned casing, thecentraliser 10 can not only rotate freely around the casing but also move freely along the casing unless and until the centraliser collides with an obstruction, for example a protruding casing joint). Thus to provide longitudinal restraint for thecentraliser 10 to retain the centraliser substantially at its preferred location along the casing but without impairing the relative rotatability of centraliser and casing, use is made of a stop collar 50, as illustrated in FIG. 6. - FIG. 6 shows a modified for of
casing centraliser 100, fitted around hollowtubular casing 102 which is located within awell bore 104. The modifiedcentraliser 100 is essentially the same as thecentraliser 10 described above, and differs principally in the dimensions and proportions of itsblades 106. In particular, theblades 106 are circumferentially wider at the lower end of thecentraliser 100 than they are at the upper end. FIG. 6 also illustrates the manner in which the centraliser will hold casing out of direct contact with the well bore and centrally within the well bore, in preparation for subsequent cementing. - FIG. 7 shows a modified
plastic centraliser 110 located around a length ofcasing 112. Thecentraliser 10 has blades R1, R2, R3 and R4 spaced around its outer surface to contact the inner surface of the wellbore and to centralise thecasing 112 therein. The blades R extend axially along the centraliser but can alternatively extend around the outer circumference of the centraliser like theblades 106. - The
centraliser 110 is axially divided along the midline of opposing blades R2 and R4 to form twoshells half shells Half shell 110 a has two threaded sockets S in each of the faces F of R2 and R4 to receive bolts B protruding through the faces F of theother half shell 110 b. The bolts B engage in the sockets S and pull the faces F together when thecentraliser 110 is made up around thecasing 112 and the bolts tightened. - The
centaliser 110 can be formed from polytetrafluoroethylene (PTFE), polyetheretheketone, carbon reinforced polyetheretherketone, polyphthalamide, polyvinylidene fluoride, polyphenylylene sulphide, polyetherimide, polyethylene, polysulphone, polyethersulphone, polybutyleneterephthalate, polyetherketoneketone, polyamides, rubber & rubber compounds, phenolic resins or compounds, thermosetting plastics, thermoplastic elastomers, thermoplastic compounds or thermoplastic polyester resins. - The
centraliser 110 is useful with coil tubing applications, but may also be used for casing and screens to afford protection from acids and other harmful chemicals downhole. - In the case of casing located within larger diameter casing, centralisers can be employed on the inner casing to hold it out of direct contact with the outer casing.
- Advantages of the invention are that the use of a plastics, elastomeric and/or rubber material for the centraliser helps to provide chemical resistance, such as resistance to corrosion from acid. Other advantages are that the materials are generally non sparking and that certain materials, for example PTFE, have superior bearing properties.
Claims (20)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GBGB9703608.1A GB9703608D0 (en) | 1997-02-21 | 1997-02-21 | Casing centraliser |
GB9703608.1 | 1997-02-21 |
Publications (2)
Publication Number | Publication Date |
---|---|
US20020023749A1 true US20020023749A1 (en) | 2002-02-28 |
US6435275B1 US6435275B1 (en) | 2002-08-20 |
Family
ID=10808063
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/378,858 Expired - Lifetime US6435275B1 (en) | 1997-02-21 | 1999-08-23 | Casing centralizer |
Country Status (4)
Country | Link |
---|---|
US (1) | US6435275B1 (en) |
AU (1) | AU6301098A (en) |
GB (2) | GB9703608D0 (en) |
WO (1) | WO1998037302A1 (en) |
Cited By (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020032126A1 (en) * | 2000-05-02 | 2002-03-14 | Kusmer Daniel P. | Borehole retention device |
US20030106719A1 (en) * | 2000-06-21 | 2003-06-12 | Herrera Derek Frederick | Centraliser |
GB2393984A (en) * | 2002-10-04 | 2004-04-14 | Polyoil Ltd | Friction reducing clamp |
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US20100206562A1 (en) * | 2006-09-18 | 2010-08-19 | National Oilwell Norway As | Centralizing device for an elongated body in a mouse hole machine |
US8245773B2 (en) * | 2006-09-18 | 2012-08-21 | National Oilwell Norway As | Centralizing device for an elongated body in a mouse hole machine |
US8167034B2 (en) * | 2008-06-19 | 2012-05-01 | Offshore Manufacturing & Design, Llc | Device for centering a well casing |
US20090314486A1 (en) * | 2008-06-19 | 2009-12-24 | Castro Mynor J | Device for Centering a Well Casing |
US9303468B2 (en) | 2010-11-02 | 2016-04-05 | National Oilwell Varco Norway As | Drilling system and a device for assembling and disassembling pipe stands |
USD665824S1 (en) * | 2011-10-28 | 2012-08-21 | Top-Co Cementing Products Inc. | Casing centralizer |
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USD983231S1 (en) | 2012-04-04 | 2023-04-11 | Summit Casing Services, Llc | Casing centralizer having spiral blades |
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US10415342B2 (en) * | 2013-02-06 | 2019-09-17 | Halliburton Energy Services, Inc. | High flow area swellable cementing packer |
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Also Published As
Publication number | Publication date |
---|---|
US6435275B1 (en) | 2002-08-20 |
GB9703608D0 (en) | 1997-04-09 |
GB9823777D0 (en) | 1998-12-23 |
GB2329209B (en) | 2000-05-24 |
WO1998037302A1 (en) | 1998-08-27 |
AU6301098A (en) | 1998-09-09 |
GB2329209A (en) | 1999-03-17 |
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