WO2015073436A1 - Composite sucker rod assembly for underground wells - Google Patents
Composite sucker rod assembly for underground wells Download PDFInfo
- Publication number
- WO2015073436A1 WO2015073436A1 PCT/US2014/065018 US2014065018W WO2015073436A1 WO 2015073436 A1 WO2015073436 A1 WO 2015073436A1 US 2014065018 W US2014065018 W US 2014065018W WO 2015073436 A1 WO2015073436 A1 WO 2015073436A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- strands
- cavity
- sucker rod
- fitting
- rod assembly
- Prior art date
Links
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Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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
- E21B17/02—Couplings; joints
- E21B17/04—Couplings; joints between rod or the like and bit or between rod and rod or the like
- E21B17/042—Threaded
- E21B17/0426—Threaded with a threaded cylindrical portion, e.g. for percussion rods
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/12—Methods or apparatus for controlling the flow of the obtained fluid to or in wells
- E21B43/121—Lifting well fluids
- E21B43/126—Adaptations of down-hole pump systems powered by drives outside the borehole, e.g. by a rotary or oscillating drive
- E21B43/127—Adaptations of walking-beam pump systems
Definitions
- the present invention relates generally to sucker rod engineering and design. More particularly, the present invention relates to a composite sucker rod assembly for use in down- hole vertical lift oil extraction.
- Sucker rods for use with vertical lift rod pumps also referred to as surface units, rocking horse, or pump jacks are typically made from individual lengths of steel rod sections that are connected together by threaded couplings.
- the individual sucker rods are typically 25 feet, 30 feet or 37.5 feet in length and are connected together with couplings to form a sucker rod string.
- a typical sucker rod string is from 700 to 10,000 feet or more in length.
- the sucker rod string connects the vertical lift surface device to the down-hole pump unit.
- Traditional metal sucker rods are heavy and subject to corrosion and fatigue failure, particularly at the threaded connections or due to stress corrosion cracking. An unexpected broken sucker rod due to corrosion and/or fatigue is expensive to remove and replace.
- the weight of a metal sucker rod string limits its strength and fatigue life and can limit the depth which even large surface units can pump.
- the weight of a steel sucker rod string can also overload and reduce the life of the surface unit and its components.
- Monolithic fiberglass sucker rods have also been in use for some time. Fiberglass sucker rods do offer a weight reduction and corrosion resistance but have significant stretch and are prone to splitting and failing due to transient compression in the rod string.
- Current sucker rod technology consists of wrought steel rods that are typically 3 ⁇ 4 inch diameter, 7/8 inch diameter, 1 inch diameter, or 1 and 1/8 inch diameter. The ends of the rods are formed to include a wrench location and machined threads to interface with couplings that join the individual rods together.
- the typical steel sucker rod lengths are 25 feet and 30 feet.
- a string of segmented sucker rods is connected between the vertical lift pumping unit at the surface and the down-hole pump at or near the bottom of the oil well.
- Shorter rods often called “Pony Rods” are used to fine tune the overall length of the sucker rod string and the position of the pump down-hole. Sinker Bars (larger diameter heavy rods) are used at the bottom of the well to weight the entire string for the down stroke.
- the sucker rods reciprocate up and down in a tube that is typically steel and suspended in the wellbore or casing. No well is perfectly straight. Steel sucker rods are stiff and often cause excessive wear on the inside of the well casing where the well is not straight. Additionally, the flex in the string induced by pumping causes metal fatigue which can cause the sucker rod to fail. The highly corrosive environment worsens the frequency of rod failures. Monolithic fiberglass sucker rods have been developed. The fiberglass rods have steel- end fittings bonded over the outside surface of each end of the monolithic fiberglass rod.
- Fiberglass sucker rods are typically larger in diameter compared to their steel counterparts. Fiberglass sucker rods have a lower tensile modulus than steel or carbon fiber and therefore exhibit more stretch than steel or carbon fiber. Fiberglass sucker rods are lighter than steel but have been known to suffer premature failure if subjected to any compression loading during the pumping cycle.
- a carbon fiber composite sucker rod pultruded as a monolithic bar and meeting the typical requirements of a sucker rod would not be attractive because it would be subject to compression failures similar to fiberglass and it would be difficult to make the terminus end fitting match the strength potential of the carbon fiber composite mid-section since it would be merely glued on the outside of the monolithic rod versus tying into the majority of the fibers.
- a continuous length steel sucker rod is also used in a small but increasing percentage of oil wells.
- Steel continuous length sucker rods require large diameter spools and special handling techniques.
- Continuous steel sucker rods are limited in the length that can be practically used due to weight, transportation and handling issues.
- Continuous length steel sucker rods are heavy, corrode, and are subject to fatigue failure.
- sucker rod assembly that can meet or exceed all operational requirements and offer significant weight reduction, complete corrosion resistance, deeper pumping capability, less maintenance, longer life and overall improved oil production economics, thus having pumping performance and service life advantages over previous sucker rods.
- the present invention addresses the aforementioned disadvantages by providing an improved sucker rod assembly for use in down-hole vertical lift oil extraction.
- the sucker rod assembly of the present invention comprises a plurality of parallel composite strength elements, referred to herein as "strands" to create a light weight, corrosion and fatigue resistant sucker rod assembly.
- the strands are made of carbon fiber, and will be described primarily as employing carbon fiber.
- other composite materials may be employed, and the invention is not intended to be limited to carbon fiber.
- the sucker rod assembly strands are made of carbon fiber manufactured by the pultrusion process or variation thereof wherein high strength fibers are drawn through a resin bath to impregnate the fibers, and then drawn through heated dies and ovens to shape, consolidate and cure the strands into generally round or polygonal cross-sections such as hexagons or octagons.
- Carbon fiber is a preferred material for the sucker rod assembly but fiberglass or other high strength fibers may also be utilized so long as they are tailored to meet the strength and stiffness requirements for the sucker rod assembly application.
- the fiber fraction of the strands should be optimized for tensile strength, stiffness, durability and handling. Additionally, the plurality of the strands that make up the sucker rod assembly should be straight and equal in length in order to maximize the overall strength of the sucker rod assembly.
- the high strength carbon fibers within a polymer matrix are bundled together in parallel to form an elongate rod. Furthermore, by altering the number of strands allows for tailoring the mechanical properties of the sucker rod assembly and the sucker rod string. A larger bundle of strands is used for the sucker rods at the top of the well (near the surface) since the upper sucker rods must carry the weight of the entire sucker rod string. A smaller bundle of strands is used for the sucker rods near the bottom of the well since the tensile stress is lower, although the weight of the lifted oil must also be taken into account.
- the overall sucker rod string is configured to meet strength and longitudinal stiffness requirements and optimize pumping efficiency.
- a carbon fiber sucker rod assembly of this configuration has been demonstrated to be approximately one-fifth the weight of steel sucker rods while retaining comparable strength.
- the sucker rod assembly of the present invention will have pumping performance and service life advantages over conventional steel or monolithic fiberglass sucker rods and continuous length steel sucker rods.
- the sucker rod assembly includes a terminus fitting at one end of the rod, and preferably at both ends of the rod.
- the terminus fittings are made of metal such as a high carbon steel. However, other metals or materials may be employed.
- Each terminus fitting has a proximal end, a distal end, and a central cavity which extends to the terminus fitting's proximal end to form a proximal opening for receipt of the elongate rod into the cavity.
- the cavity flares outwardly from the fitting's proximal end toward said fitting's distal end.
- the terminus fitting's central cavity extends from the fitting's proximal opening to the terminus fitting's distal end to form a distal opening.
- the distal opening may include a female thread for affixing to a male threaded member.
- the elongate rod's plurality of strands are splayed-out within the terminus fitting and encapsulated with a polymer resin or ceramic material which hardens within the terminus fitting's cavity to form a tapered wedge that holds the terminus fitting in place on the plurality of strands.
- the terminus polymer or ceramic wedge is cast by injecting the material into an injection port which projects through the side of the terminus fitting. When injected into the injection port, the material fills the space around the strands. A vent is provided to allow air to vent from the central cavity and to give a visual assurance that the tapered cavity is properly filled with material.
- the tapered cavity is preferably conical and injected or filled with a polymer material that adheres to the strands to form a mechanical cone shaped wedge within the terminus fitting.
- the polymer material for the terminus wedge can be epoxy, phenolic or other thermosetting resin meeting the performance requirements.
- a heat resistant ceramic material may be used for the terminus wedge.
- a preferred method for assembling the carbon fiber sucker rod assembly is to inject the polymer or ceramic material directly into the terminus fitting.
- two ports in the terminus fitting are used for the wedge material injection.
- One port is an injection port to inject the polymer or ceramic into the fitting.
- the other port is a vent hole which provides a temporary vent and a sight window to show that adhesive resin has filled the tapered cavity.
- the polymer or ceramic wedge material is injected into the terminus fitting while the terminus fitting is lying in a horizontal position.
- At least one spreader plate is positioned within the terminus fitting's cavity.
- the spreader plate is preferably planar and substantially round so as to define a central axis.
- the spreader plate is positioned within the terminus fitting's central cavity with the spreader plate's central axis coincident with the cavity's central axis.
- the spreader plate has a diameter slightly smaller than the diameter of the terminus fitting's cavity at the spreader plate's location within the central cavity.
- the spreader plate has a plurality of holes which receives the rod strands so as to splay out the strands in a widened orientation compared to where the strands enter the terminus fitting's proximal opening.
- the spreader plate is constructed of two or more pieces wherein each piece includes an engagement edge for engaging an engagement edge of an adjoining piece.
- the pieces are held together to form a single spreader plate simply by the rod strands forcing the pieces radially together to engage one another.
- the engagement edges of the spreader plate pieces include one or more indents for engaging indents formed in the engagement edges of adjoining pieces so that adjoining indents of adjoining pieces form holes which receive the strands.
- the spreader plate pieces also include a peripheral edge where the pieces do not engage an adjoining piece such as where the spreader plate periphery is adjacent to the terminus fitting's cavity wall. It is preferred that the peripheral edge of each piece include one or more indents for receiving and splaying out one or more strands in a widened orientation compared to where the strands pass through said terminus fitting's proximal opening.
- annular spacer is applied over the ends of the strands to maintain the strands in a splayed configuration within the terminus fitting while a polymer is injected into the fitting and cured.
- the annular spacers are positioned longitudinally on the strands at approximately the same location so as to engage one another.
- the annular spacers may be longitudinally positioned at different locations so as to engage adjoining strands.
- the sucker rod assembly includes a connection member for connecting to other sucker rod assemblies or other equipment.
- a preferred connection member has a male threaded end which affixes to the terminus fitting's female thread.
- the connection member projects into the cavity sufficient such that the connection member engages the tapered wedge to place the wedge in a state of compression. This construction results in putting a pre-load on the tapered wedge which enhances its ability to handle cyclic tension and compressive loads.
- the preferred method to compress the wedge within the terminus fitting is to inject the polymer or ceramic material into the terminus with the threaded connection member backed out slightly from its final (not fully torqued) position. After the wedge is cured, the threaded connection member is fully screwed in place and torqued as appropriate.
- Another option is to use a dummy connection member when the polymer or ceramic wedge is injected into the fitting. This dummy connection member can be slightly shorter than the final connection member so a compressive load is applied to the wedge when the final connection member is installed.
- a minimum number of strands are preferably bundled together to form a length of the composite sucker rod assembly.
- the plurality of parallel strands may be fully over-wrapped with an encapsulating layer of composite or polymer material that holds the bundle together and provides a wear resistant covering.
- the over-wrap may also be spaced incrementally to keep the bundle together, thereby increasing the overall stiffness of the sucker rod assembly and providing tailored dampening for compressive loads.
- the bundle of strands is preferably held together with a composite wrap spaced incrementally sufficient to hold the bundle of rods together but allow them to flex between the wrap if the rod experiences a compressive load. The spacing and the length of the incremental composite wraps can be used to tailor the compressive stiffness of the overall carbon composite sucker rod assembly.
- the plurality of parallel strands are preferably bundled in a generally polygonal or round package so the sucker rod assembly can be progressively rotated in a well tubing as typically done to prevent wear in one spot. It is also necessary for the strands to splay-out evenly in the terminus without crossing one strand over another.
- Wear guides and paraffin scrapers may be installed along the length of the composite sucker rod assembly after it is assembled. Wear guides are typically used only on sucker rods running in a deviated portion of the oil well.
- a preferred method is to mold a fiber filled composite wear guide directly onto the bundle of strands. This can be accomplished by infusion molding a relatively thick three dimensional fiber mat that is wrapped around the strands bundle. A two piece mold is clamped around the wrapped fiber form.
- Thermosetting epoxy is injected into the mold and flows through the porous spun polyester material. When cured, the mold is removed.
- the three dimensional spun polyester mat impregnated with epoxy forms a wear resistant composite particularly suited for application that is permanently bonded over the sucker rod.
- the wear guides can also function as wraps incrementally spaced to provide the desired compressive dampening and rod stiffness, as described above.
- a preferred method is to mold the composite wear guide over an incrementally spaced band in order to maintain the desired band spacing.
- woven fiberglass, carbon fiber or aramid fiber cloth tape can be convolutely wrapped with resin around the bundle of carbon fiber rods such that it functions both as a wear band and the banding that holds the plurality of rods together.
- FIG. 1 is an exploded perspective view of a composite sucker rod assembly of the present invention
- FIG. 2 is a side cut-away view of a composite sucker rod assembly of the present invention
- FIG. 3 is an exploded cut-away view of a composite sucker rod assembly of the present invention.
- FIG. 4 is a side cut-away view of a composite sucker rod assembly of the present invention illustrating a first cavity configuration
- FIG. 5 is a side cut-away view of a composite sucker rod assembly of the present invention illustrating a second cavity configuration
- FIG. 6 is a side cut-away view of a composite sucker rod assembly of the present invention illustrating a third cavity configuration
- FIG. 7 is a side cut-away view of a composite sucker rod assembly of the present invention illustrating injection of resin into the cavity;
- FIG. 8 is an exploded perspective view of a spreader plate of the present invention.
- FIG. 9 is a perspective view of a spreader plate of the present invention.
- FIG. 10 is a top view of a first spreader plate of the present invention.
- FIG. 11 is a top view of a second spreader plate of the present invention.
- FIG. 12 is a top view of a third spreader plate of the present invention.
- FIG. 13 is a top view of a fourth spreader plate of the present invention.
- FIG. 14 is a side view of a sucker rod assembly of the present invention including wear guides.
- the sucker rod assembly 10 includes a plurality of strands 20 forming an elongate rod 15.
- the sucker rod assembly 10 further includes a terminus fitting 30 having a central cavity 33, a spreader plate 22, and connection member 45.
- a plurality of sucker rod assemblies are connected together to form a sucker rod string 11 to connect a vertical lift surface device to a down-hole pump unit.
- the composite sucker rod assembly 10 comprises a plurality of generally round strands 20 that are bundled together to form the elongate rod 15.
- the tensile strength and stiffness of the composite rod assembly 15 is determined by the composite materials used for the individual strands 20, the size of the strands 20, and the number of strands 20 bundled together to make the rod 15.
- the carbon composite sucker rod strands 20 are manufactured by the pultrusion process or variation thereof wherein high strength fibers are drawn through a resin bath to impregnate the fibers and then through heated dies and ovens to shape, consolidate and cure the strands 20 into generally round rods or similar shapes such as hexagons or octagons.
- Carbon fiber is the preferred material for the plurality of parallel strands 20 but fiberglass or other high strength fibers may also be utilized so long as they are tailored to meet the strength and stiffness requirements for the sucker rod assembly application.
- the polymer matrix within the strands 20 may be epoxy, polyester, vinyl ester, cyanurate ester, benzoxyzene, phenolic or other suitable thermosetting resins.
- Thermoplastic polymer matrices such as PEI, PEEK, PPS or other suitable polymers may also be used by modifying the pultrusion process to heat, consolidate and shape, and chill the polymer and fiber matrix into usable composite strands.
- the fiber fraction of the strands 20 should be optimized for tensile strength, stiffness, durability and handling.
- the ideal size of the strands 20 is roughly from 1/8 ⁇ inch diameter to 3/ 16 th inch diameter although other sizes may be used and the ideal size may be dependent on processing and assembly requirements.
- the cross sectional area of typical sucker rods can be pultruded at roughly 10 times the through-put speed when they are made as a plurality of strands versus as a monolithic rod, as such this lowers production cost. Even with the additional steps to cut and bundle the strands, the overall production cost of a carbon fiber composite sucker rod made from a plurality of strands is generally lower than an equivalent monolithic version.
- the strands it is also necessary for the strands to be large enough in cross section for ease of handling and to lay straight in the tooling used for assembly of the sucker rod.
- the plurality of the strands 20 that make up the rod 15 should be straight and equal in length in order to maximize the overall strength of the rod 15. If one strand is shorter than the others in the bundle, then that strand is loaded more than the others and would fail prematurely under a tensile load condition.
- the strands 20 be approximately 1/8 inch or larger in diameter to be stiff enough to be assembled in typical assembly tools maintaining equal length and straightness of the strands 20 without methods to pre-tension the strands. Unlike prior manufacturing processes, tensioning the strands 20 during assembly is not necessary as that would be time consuming and costly.
- a minimum number of strands 20 are preferably bundled together to form a length of the elongate rod 15.
- the bundle of strands 20 is preferably held together with composite wraps 50 spaced incrementally sufficient to hold the bundle of rods together, but allow them to flex between the wrap 50 if the rod experiences a compressive load.
- the spacing and the length of the incremental composite wraps 50 can be used to tailor the compressive stiffness of the overall carbon composite sucker rod 50.
- spacing the composite wraps 50 and/or wear guides at approximately 10-30 times the bundle diameter is ideal to provide compressive dampening yet make the overall rod stiff enough for handling.
- the composite wraps 50 and/or wear guides are spaced at 15-25 times the bundle diameter, and the preferred distance between wraps is approximately 20 times the bundle diameter.
- the plurality of parallel strands 20 are preferably bundled in a generally polygonal or round package so the sucker rod assembly 10 can be progressively rotated in a well casing as typically done to prevent wear in one spot.
- the diameter of the carbon fiber sucker rod assembly 10 is significantly less than its equivalent steel counterpart.
- the equivalent carbon fiber sucker rod assembly 10 replacing a 1-1/8 inch diameter steel sucker rod is just under 1 inch diameter.
- the sucker rod assembly's terminus fittings 30 may be affixed at one or both ends of the sucker rod assembly 10.
- the terminus fittings are preferably made of metal, and more preferably made of a high carbon steel. Other materials including carbon fiber may be employed.
- Each terminus fitting 30 has a proximal end 31 and a distal end 32.
- a cavity 33 extends the length of the terminus fitting from its proximal end to its distal end so as to form a proximal opening 35 and a distal opening 36.
- the cavity 33 has a tapered construction so as to have a smaller diameter at its proximal opening 35 than toward its distal end.
- the central cavity has a conical section 37 towards the terminus fitting's proximal end 31 and a substantially cylindrical section 38 towards the terminus fitting's distal end 32.
- the cavity's proximal opening 35 is sized to receive one end of the elongate rod 15 and its individual strands 20.
- the cavity's distal opening 36 includes a female thread 41 for affixing to a male threaded member.
- the sucker rod assembly 10 To lock the strands 20 within the terminus fitting's cavity 33, the strands are splayed out so as to have a diameter greater than the terminus fitting's proximal opening 35.
- the sucker rod assembly 10 includes a spreader plate 22 positioned within the terminus fitting's cavity 33.
- the spreader plate is preferably planar and substantially round so as to define a central axis.
- the spreader plate 22 has a plurality of holes 23 for receiving the rod strands 20 so as to splay the strands in a widened orientation compared to where the strands enter the terminus fitting's proximal opening 35.
- the spreader plate has a diameter slightly smaller than the diameter fitting's cavity 33 where the spreader plate has been positioned within the cavity 33. Furthermore, preferably the spreader plate's central axis is coincident with the cavity's central axis. As would be understood by those skilled in the art, the diameter of a preferred spreader plate would be smaller when positioned within the cavity's conical section 37 than if the spreader plate 22 were positioned in the cavity's cylindrical section 38.
- the spreader plate 22 is constructed of two or more pieces 24 wherein the pieces can be arranged to adjoin one another to form a single spreader plate 22.
- Each of the spreader plate pieces 24 include an engagement edge 25 where it engages the engagement edge of an adjoining piece 24.
- these engagement edges 25 include indents 27 which align and adjoin indents formed in adjoining pieces to form holes 23 for receiving the rod strands 20.
- the spreader plate pieces 24 also include a peripheral edge 26 where the pieces do not engage an adjoining spreader plate piece 24. It is preferred that these peripheral edges also include indents 27 sized for receiving a rod strand 20. As illustrated in FIGS.
- the sucker rod assembly 10 may include any number of spreader plates so as to maintain the strands 20 properly aligned and positioned to prevent withdrawal of the elongate rod 15 from the terminus fitting 30.
- FIG. 5 illustrates a sucker rod assembly 10 with two spreader plates 22.
- the sucker rod assembly includes a plurality of annular spacers wherein an annular spacer is applied over the ends of each the strands to maintain the strands in a splayed configuration.
- the annular spacers may be positioned longitudinally upon the strands at approximately the same location so that the periphery of each annular spacer engages the periphery of an adjoin spacer.
- the annular spacers may be longitudinally positioned at different locations so that the periphery of an annular spacer engages adjoining strands.
- terminus fitting's tapered cavity 33 may include a conical section 37 and a cylindrical section 38. If it is desirable to minimize the size of the terminus fitting 30, the cavity's conical section 37 can be shorter in length provided the overall cavity length is retained. More specifically, shortening the length of the conical section 37 while retaining the overall length of the cavity 33 enables one to maintain the wedge effect of affixing the rod 15 to the terminus fitting 30 and thus maintain the overall adhesive shear strength of the wedge 21 to the rod 15 when the size of the fitting is constrained.
- FIG. 7 illustrates a terminus fitting where the conical portion 37 is shorter than the cylindrical portion 38.
- FIG. 6 illustrates a terminus fitting where the conical portion 37 is longer than the conical portion illustrated in FIG. 5.
- the terminus fitting's cavity 30 (as illustrated in FIG. 7) is preferably injected or filled with a polymer material that adheres to the strands 20 and forms a mechanical tapered wedge 21 within the terminus fitting 30.
- the polymer material for the wedge 21 can be epoxy, phenolic or other thermosetting resin meeting the performance requirements.
- a heat resistant ceramic material may be used within the terminus cone.
- the preferred method for assembling the carbon fiber sucker rod 10 is to inject the polymer or ceramic resin material directly into the terminus fitting 30.
- an injection port 39 and vent port 40 are used for the resin material injection.
- the injection port 39 is provided to inject the polymer or ceramic resin into the fitting 30.
- the vent port provides a temporary vent and a sight window to show that adhesive has filled the cavity 30.
- the polymer or ceramic material is injected into the injection port 39 while the terminus fitting 30 is lying in a horizontal position. It is important to assemble the composite sucker rod 10 in a horizontal position with the plurality of strands 20 supported substantially straight and in the desired bundle configuration with the terminus end fittings 30 properly aligned before the resin material is injected into the terminus fitting's injection port 39. It is also important for the splayed orientation of the strands 20 to be configured properly and consistent.
- the sucker rod assembly 10 includes a threaded connection member 45 to interface with a standard sucker rod coupling that connects rod to rod to form a sucker rod string.
- the threaded connection member 45 can be applied on only one end of the sucker rod 10 and no threaded connection member is affixed to the other end. This enables one sucker rod 10 to be coupled to another without the use of traditional sucker rod couplings. Instead, the connection member 45 of one sucker rod assembly 10 threads into the female threaded opening 36 of the other sucker rod assembly 10.
- the hardened resin wedge 21 with the male threaded portion of the connection member 45 as a means to firmly hold the wedge 21 in position within the terminus fitting 30, especially when it is anticipated that the sucker rod assembly will experience compressive loads.
- the preferred method to compress the wedge 21 within the terminus 30 is to inject the polymer or ceramic resin into the terminus 30 with the threaded connection member 45 backed out slightly, for example, approximately 1/8 to 1 ⁇ 2 turn, from its final position or not fully torqued. As a result, the wedge 21 will be in-situ molded within the terminus 30. After the wedge 21 is cured, the threaded connection member 45 is fully screwed in place and torqued as appropriate.
- This method results in putting a pre-load on the wedge 21 which enhances its ability to handle cyclic tension and compressive loads.
- Another option is to use a dummy connection member (not shown) when the polymer or ceramic wedge is injected into the fitting 30. This dummy connection member can be slightly shorter than the final connection member 45 so a compressive load is applied to the wedge 21 when the final connection member 45 is installed.
- wear guides 50 and/or paraffin scrapers may be installed along the length of the composite sucker rod assembly 10.
- Wear guides 50 are typically used only on sucker rods running in a deviated portion of the oil well.
- Traditional wear guides are made from a thermoplastic polymer and are pre-molded and snapped in place or injection molded directly onto the steel sucker rod.
- Traditional wear guides often do not stay in place during operation.
- a fiber filled composite wear guide 50 is molded directly onto the bundle of strands 20. This can be accomplished by infusion molding a relatively thick three dimensional fiber mat that is wrapped around the strands bundle.
- the fiber form is a wear resistant spun polyester mat made by 3M that is from 1 ⁇ 4 to 3/8 inch thickness.
- a 3 - 4 inch wide by 9-12 inch long strip of 1 ⁇ 4 inch thick spun polyester mat is wrapped around the plurality of strands 20 of the sucker rod assembly 10 at the location desired for the wear guide 50.
- a two piece mold is clamped around the wrapped fiber form.
- Thermosetting epoxy is injected into the mold through an injection port to flow through the porous spun polyester material. When cured, the mold is removed.
- the three dimensional spun polyester mat impregnated with epoxy forms a wear resistant composite particularly suited for application that is permanently bonded over the sucker rod assembly 10.
- the wear guides 50 can also function as wraps incrementally spaced to provide the desired compressive dampening and rod stiffness, as described above.
- woven fiberglass, carbon fiber or aramid fiber cloth tape can be convolutely wrapped with resin around the bundle of carbon fiber rods such that it functions both as a wear guide and the banding that holds the plurality of rods together.
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA2929586A CA2929586A1 (en) | 2013-11-12 | 2014-11-11 | Composite sucker rod assembly for underground wells |
US15/149,387 US20160362939A1 (en) | 2013-11-12 | 2014-11-11 | Composite sucker rod assembly for underground wells |
CN201480070063.2A CN105874149A (en) | 2013-11-12 | 2014-11-11 | Composite sucker rod assembly for underground wells |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201361903194P | 2013-11-12 | 2013-11-12 | |
US61/903,194 | 2013-11-12 | ||
US201462003437P | 2014-05-27 | 2014-05-27 | |
US62/003,437 | 2014-05-27 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2015073436A1 true WO2015073436A1 (en) | 2015-05-21 |
Family
ID=53057939
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2014/065018 WO2015073436A1 (en) | 2013-11-12 | 2014-11-11 | Composite sucker rod assembly for underground wells |
Country Status (4)
Country | Link |
---|---|
US (1) | US20160362939A1 (en) |
CN (1) | CN105874149A (en) |
CA (1) | CA2929586A1 (en) |
WO (1) | WO2015073436A1 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2016145289A1 (en) * | 2015-03-12 | 2016-09-15 | Lifting Solutions Usa, Inc. | Sucker rod terminus assembly for underground wells |
BR112019005836B1 (en) * | 2016-09-23 | 2023-01-17 | Richard V. Campbell | REVERSE INJECTION METHOD FOR ATTACHING A TERMINAL TO A STRING LIMB |
CN110700796A (en) * | 2019-09-17 | 2020-01-17 | 大庆市汇成科技开发有限公司 | Intelligent carbon fiber continuous flexible sucker rod long-stroke large-pump deep pumping oil production system |
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US7137617B2 (en) * | 2001-07-16 | 2006-11-21 | Air Logistics Corporation | Composite tensioning members and method for manufacturing same |
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US3123879A (en) * | 1964-03-10 | Wedge anchor for tensioning and anchoring wires | ||
US2652231A (en) * | 1949-10-03 | 1953-09-15 | Roy A Smith | Pumping assembly |
US2856662A (en) * | 1957-04-17 | 1958-10-21 | Earl D Clark | Cable shackle |
GB987107A (en) * | 1961-11-22 | 1965-03-24 | Peter Philip Riggs | Improvements in end fittings for wire ropes and the like |
US3660887A (en) * | 1969-06-20 | 1972-05-09 | Nupla Corp | Method for connecting attachments to fiber glass rods |
ES199828Y (en) * | 1974-01-25 | 1975-12-16 | Manufacturas De Acero | DEVICE FOR ANCHORING BRAIDS AND CORDS OF CONSTRUCTION WEAPONS. |
US4367568A (en) * | 1980-05-24 | 1983-01-11 | Strabag Bau-Ag | Anchorage devices for a tension wire bundle of tension wires |
US4430018A (en) * | 1983-04-11 | 1984-02-07 | Technicraft, Inc. | End fitting for oil well sucker rods |
CA2047013C (en) * | 1991-07-08 | 1994-12-13 | Doug Milne | Cable grip |
DK0710313T3 (en) * | 1994-04-25 | 2000-09-25 | Empa | Anchoring for high performance fiber composite threads |
CN1258805A (en) * | 1999-12-10 | 2000-07-05 | 胜利石油管理局工程机械总厂 | Pumping rod of composite carbon fiber material and its manufacture |
CN1796723A (en) * | 2004-12-27 | 2006-07-05 | 吴永春 | Hollow sucker rod prepared from composite material fiber |
US8286309B2 (en) * | 2008-06-10 | 2012-10-16 | Actuant Corporation | Median barrier cable termination |
WO2014188469A1 (en) * | 2013-05-20 | 2014-11-27 | 極東鋼弦コンクリート振興株式会社 | Anchoring device for fiber reinforced plastic filament |
-
2014
- 2014-11-11 CN CN201480070063.2A patent/CN105874149A/en active Pending
- 2014-11-11 WO PCT/US2014/065018 patent/WO2015073436A1/en active Application Filing
- 2014-11-11 US US15/149,387 patent/US20160362939A1/en not_active Abandoned
- 2014-11-11 CA CA2929586A patent/CA2929586A1/en not_active Abandoned
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
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US3909142A (en) * | 1972-12-05 | 1975-09-30 | Ccl Systems Ltd | Coupling assembly for stressing tendons of multi-span concrete structures |
US4673309A (en) * | 1984-09-25 | 1987-06-16 | Schlaich Joerg | Method and apparatus for anchoring cables of high-tensile steel wire |
US20050002733A1 (en) * | 1997-03-07 | 2005-01-06 | Deep Water Composites As | Tension member termination |
US6487757B1 (en) * | 1999-09-15 | 2002-12-03 | Freyssinet International (Stup) | System for connecting a structural cable to a building work structure |
US7137617B2 (en) * | 2001-07-16 | 2006-11-21 | Air Logistics Corporation | Composite tensioning members and method for manufacturing same |
Also Published As
Publication number | Publication date |
---|---|
CA2929586A1 (en) | 2015-05-21 |
CN105874149A (en) | 2016-08-17 |
US20160362939A1 (en) | 2016-12-15 |
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