Universal Wireline Standoff

The present invention relates to wireline logging and, more particularly, in one or more embodiments, the present invention relates to a device for improving wireline cable performance during logging operations in a variety of boreholes.

Wireline logging is a common operation in the oil industry whereby down-hole electrical tools may be conveyed on a wireline (also known as an “e-line”) to evaluate formation lithologies and fluid types in a variety of boreholes. In certain wells, there may be a risk of the wireline cable and/or logging tools becoming stuck in the open hole due to differential sticking or key-seating, for example.

Key-seating may occur when the wireline cable operates similar to a saw and cuts a groove into the borehole wall. Such cable grooves may be observed with wireline imaging tools. Once a cable groove has been cut, various sticking mechanisms may act on the wireline cable. For instance, the wireline cable may be trapped via compression. In addition, the wireline cable may be trapped in the groove by borehole stress. Moreover, mechanical binding of the wireline cable in a deep groove may occur. In instances in which the rock is permeable, differential sticking of the wireline cable may also occur. This may happen in deviated or directional wells where the wireline cable may exert sustained sideways pressure at the contact points with the borehole. Furthermore, since the logging tool diameter is generally much larger than the groove cut by the wireline cable, a key-seat may terminate normal ascent out of the borehole and potentially result in a fishing job or lost tools in hole.

Differential sticking may occur when there is an overbalance between hydrostatic and formation pressures in the borehole, the severity of which may be related to a number of issues, including: (1) the degree of overbalance and the presence of any depleted zones in the borehole; (2) the character and permeability of the formations bisected by the borehole; (3) the deviation of the borehole, since the sideways component of the tool weight adds to the sticking forces; (4) the drilling mud properties in the borehole, since the formation of mud cakes may trap logging tools and the wireline cable against the borehole wall; and (5) the geometry of the toolstring being logged on a wireline, since a long and large toolstring may present a larger cross sectional area and may result in proportionally larger sticking forces. Additionally, during wireline formation sampling, the logging tools and wireline may remain stationary over permeable zones for a long period of time, which may also increase the likelihood of differential sticking. Further, active loss zones in the wellbore may apply high sideways force and may stick the logging cable or tools.

These and other needs are addressed by an embodiment of a wireline assembly having a wireline cable. The wireline assembly also has a logging tool-string and a jar. The wireline assembly further has one or more wireline standoffs located on the wireline cable above the jar. Each of the one or more wireline standoffs has a cable insert disposed between a pair of opposing assemblies. The cable insert has an anti-rotation spigot. In addition, the cable insert comprises aluminum or silicon bronze, depending on well fluid and corrosive properties.

These and other needs are addressed by an embodiment of a method of reducing cable friction above a jar of a wireline assembly. The method includes providing a wireline assembly having a wireline cable and a jar. The method also includes securing one or more wireline standoffs to the wireline cable above the jar. Each of the one or more wireline standoffs has a cable insert disposed between a pair of opposing assemblies. The cable insert has an anti-rotation spigot. In addition, the cable insert comprises silicon bronze. Moreover, the method includes conveying the wireline assembly into a borehole. Additionally, the method includes reducing a cable friction caused by the wireline cable contacting a wall of the borehole. The reducing results from the one or more wireline standoffs lowering an area of contact between the wireline cable and the wall of the borehole.

These and other needs are addressed by an embodiment of a method of assembling a wireline assembly. The method includes disposing a wireline assembly having a wireline cable and a jar into a borehole. The method also includes placing two parts of a cable insert around the wireline cable at a location above the jar. The cable insert includes an anti-rotation spigot. In addition, the cable insert comprises silicon bronze. Further, the method includes securing the two parts of the cable insert to each other. Additionally, the method includes placing a pair of opposing assemblies around the cable insert. Moreover, the method includes securing the pair of opposing assemblies to each other. The method also includes repeating the above-noted steps at a different location on the wireline cable above the jar.

An embodiment includes a wireline standoff. The wireline standoff may comprise a pair of opposing assemblies. The opposing assemblies may each comprise a half shell, a cable insert configured to be disposed in the half shell, and external fins coupled to the half shell. The wireline standoff further may comprise one or more fasteners configured to couple the opposing assemblies to one another.

Another embodiment includes a wireline assembly. The wireline assembly may comprise a wireline cable and a wireline standoff. The wireline standoff may comprise a pair of opposing assemblies, wherein each of the opposing assemblies may comprise a half shell, a cable insert disposed in the half shell, and external fins coupled to the half shell. The cable insert for each of the opposing assemblies may be coupled to the wireline cable.

Yet another embodiment may comprise a method for reducing sticking in wireline logging. The method may comprise coupling one or more wireline standoffs to a wireline cable. The one or more wireline standoffs may comprise a pair of opposing assemblies, wherein each of the opposing assemblies may comprise a half shell, a cable insert configured to be disposed in the half shell, and external fins coupled to the half shell.

The features and advantages of the present invention will be readily apparent to those skilled in the art. While numerous changes may be made by those skilled in the art, such changes are within the spirit of the invention.

The present invention relates to wireline logging and, more particularly, in one or more embodiments, the present invention relates to a device for improving wireline cable performance during logging operations in a variety of boreholes.

As shown in the embodiments of, there may be several advantages to wireline standoffand methods of use thereof, only some of which may be alluded to herein. Advantages include corrosion protection of cable insert. An additional advantage includes that cable insertmay be used with water-based mud. Another advantage is that wireline standoffand methods of use may ameliorate the effects of differential sticking and/or key-seating of wireline cableby reducing or eliminating direct contact of wireline cableto borehole wall. In accordance with present embodiments, this may be achieved by coupling a plurality of wireline standoffsonto wireline cable, resulting, for example, in a lower contact area per unit length of open hole, lower applied sideways pressure of wireline cableagainst borehole wall, and/or lower cable drag when conveying wireline cablein or out of borehole. Another advantage is that the use of wireline standoffsmay also enable more efficient use of wireline jars in the logging string, since wireline standoffsmay reduce the cable friction above the jars. Lower cable drag may facilitate more sufficient energy transfer from wireline cableto the jar hammer, which may result in a more reliable jar firing and a more efficient re-cocking. Without wireline standoffson wireline cable, the high cable drags generated during the jar firing may attenuate the hammer impact velocity and may result in failure to free the logging tools. Furthermore, without wireline standoffson wireline cable, re-cocking the jar may be problematic due to excessive cable stiction, having just pulled wireline cableinto a groove when firing the jar at higher tension. The subsequent cable peel-off force may be significant and may impede re-cocking. A freely moving wireline cableabove the jar may be desired, especially in deviated or tortuous wells where tension transmission may be sub-optimal from the vertical well scenario. Not being able to re-cock the jar may mean the jar may not be fired again, and the wireline tools may need to be fished. The cable drag imparted to wireline cablemay increase the jar firing tension and may reduce jar hammer impact velocity and any or substantially any resulting impulse. In embodiments, when deciding on a location of wireline standoff, the location may be selected to reduce a friction caused by wireline cablecontacting borehole wall. Such location may result in a lower surface cable tension when logging up out of borehole, and a higher surface cable tension when logging down in borehole.

Referring now to, a wireline standoffis illustrated. In embodiments, wireline standoffmay comprise two opposing assemblies, which mate together onto wireline cable. A variety of different fasteners may be used to couple the two assembliesto one another. By way of example, bolts, dowel pins, or any combinations thereof may be used. In an embodiment, a combination of dowel pins (illustrated, e.g., by reference numberon) and boltsmay be used to couple assembliesto one another. In one particular embodiment, four cap head boltsand four dowel pinsmay be used for coupling assemblies. Dowel pinsmay be used, for example, to resist shear forces. In an embodiment, dowel pinsare 4×8 mm pins.

As further illustrated in, each of opposing assembliesmay comprise a corresponding half shellwhich contains a cable insert. As shown, wireline standoffcontains two cable insertswith each of opposing assembliescontaining a corresponding cable insert. In an embodiment, cable insertsmay be secured in their half shellsby a fastener, such as, for example, recessed cap head bolt. In an embodiment, contact with the exterior of wireline cablemay be solely with cable insertsand not half shells. In one particular embodiment, cable insertsmay be configured to clamp directly onto wireline cableusing bolts. In an embodiment, cable insertsmay mate to form a central borethrough wireline standoff. Cable insertsmay be configured to slightly deform around outer wireline cablearmour during installation without physically damaging wireline cable. It is to be understood that there are a large range of cable insertsavailable to fit wireline cable, taking into account any manufacturing tolerances and varying degrees of wear or distortion along the length of wireline cable. Therefore, for a plurality of wireline standoffsinstalled on wireline cable, a range of different cable insertsmay be employed, for example, to ensure a fit which may not allow slippage along wireline cableor damage to wireline cablewhen coupled. Boltsthat may be used to couple the two assembliestogether may be torqued to a consistently safe limit with a calibrated torque wrench.

Half shellsmay comprise a suitable material, such as stainless steel or other high-performance material. In an embodiment, half shellsmay constructed from stainless steel. In addition, half shellsmay be surface hardened (e.g., vacuum hardened or laser hard coated), in certain embodiments, for improved wear resistance during use. A wide range of shell sizes are available for installation on wireline cable, from an outside diameter of about 50 mm and greater, for example. In an embodiment, half shellsmay have an outside diameter of about 75 mm. In an embodiment, the maximum external diameter of wireline standoffis less than the size of the internal diameters of the overshot and drill pipe that may be used in fishing operations so that wireline standoffmay be safely fit inside a fishing assembly enabling the wireline cable head or tool body to be successfully engaged by the fishing overshot. In this manner, wireline cableand wireline standoffmay then be safely pulled through the drill pipe to the surface when the cable head is released from the logging string.

Cable insertsmay comprise any suitable material, such as aluminum or silicon bronze. In embodiments, cable insertsmay comprise silicon, bronze, or any combinations thereof. In an embodiment, cable insertsmay comprise silicon bronze. Cable insertsmay comprise any suitable silicon bronze. In some embodiments, cable insertscomprise high silicon bronze. An example of a suitable high silicon bronze is C65500 high silicon bronze. Embodiments include cable insertscomprising high silicon bronze that comprises copper, tin, silicon, or any combinations thereof. Some embodiments include cable insertscomprising high silicon bronze that comprises copper, iron, lead, manganese, nickel, silicon, zinc, or any combinations thereof. In an embodiment, high silicon bronze has at least about 97.0 wt. % copper; alternatively about 97.0 wt. % copper and about 3.0 wt. % silicon; and alternatively about 95.8 wt. % copper, about 3.3 wt. % silicon, and about 0.9 wt. % manganese; further alternatively about 91.95 wt. % to about 93.75 wt. % copper, about 0.8 wt. % iron, about 0.05 wt. % lead, about 0.50 wt. % to about 1.3 wt. % manganese, about 0.6 wt. % nickel, about 2.8 wt. % to about 3.8 wt. % silicon, and about 1.5 wt. % zinc. Without limitation, it is to be understood that silicon bronze has good corrosion properties and has similar mechanical properties to aluminum. In an embodiment, cable insertsare a durable item but may be junked in the event of damage during a logging run. Furthermore, in some embodiments, cable insertsmay be positively secured into each of the half shellsby fasteners(e.g., small cap head bolts) that pass through the outside of each of half shellsinto tapped holes in cable inserts. In embodiments, cable insertsmay have no movement inside half shells. For example, a central spigot (see, e.g., anti-rotation spigoton) may be included to reduce or even eliminate rotation of cable insertsin half shells. By way of further example, a central flange (see, e.g., cable insert flangeon) on cable insertsmay be used to ensure little to no axial movement in half shells.

Wireline standoffmay further include a plurality of finscoupled to half shells. Among other things, finsmay allow easy movement along boreholeand through mud cake and other debris, which may have accumulated in boreholeduring drilling. In an embodiment, finsmay be arranged along the length or a portion of the length of half shells. In an embodiment, wireline standoffmay comprise twelve fins. In an embodiment, finsmay be distributed radially along the length of half shells. The empty space between finsmay allow for circulation of drilling mud inside drill pipe if wireline cableand wireline standoffare fished using drill pipe. In an embodiment, finshave a low coefficient of friction. Finsmay have a smooth radial cross section to minimize the contact area with borehole walland allow for standoff rotation under the action of cable torque. It is believed that this may reduce the differential sticking force acted upon each finat the contact points with borehole walland may also allow for easy rotation of wireline standoffsif wireline cablerotates when it is deployed and retrieved from borehole. It should be noted that it is the general nature of wireline cableto rotate during logging operations due to the opposing lay angles of the inner and outer armours, which may induce unequal torsional forces when tensions are applied. The design of wireline standoffsmay allow easy rotation of wireline cableduring the logging operation, avoiding, for example, the potential for damage if excessive torque was allowed to build up.

In addition, wireline standoffmay further include a plurality of holesin half shells. In an embodiment, holesmay extend across half shellsfor use in installation. By way of example, holesmay be used to connect wireline standoffto a lanyard during installation to avoid dropped objects on the drill floor during installation on wireline cable. In an embodiment, each of half shellsmay contain four holes. In embodiments, holesare disposed radially about opposite ends of wireline standoff.

illustrates a section of wireline cablepassing through central bore(shown, e.g., on) of cable insertsin wireline standoff. As illustrated, boltshold half shellstogether while clamping cable insertsonto wireline cable, in accordance with certain embodiments. The diameter of wireline cablemay vary (e.g., about 8 to about 16 mm), for example, depending on, without limitation, the logging vendor. In an embodiment, cable insertsmay be matched to the diameter of wireline cableregardless of any variations in size or profile that might occur along the length of wireline cable. As previously mentioned, cable insertsmay comprise aluminum or silicon bronze, both may be softer than the plough steel of the wireline cablearmour. It is desirable to reduce the risk of damage to wireline cableduring installation of wireline standoff. By way of example, an accurate fit of cable insertson wireline cableand, in certain embodiments, the controlled torque of boltsduring installation may reduce the risk of damage to wireline cablefrom cable insertswhen boltsare tightened, pulling the two half shellstogether and cable insertsinto contact with wireline cable. A calibrated nut-runner may be employed to apply consistent torque to bolts.

In an embodiment, one or more of the wireline standoffsmay be used on a wireline cable. In embodiments, installation of a plurality of wireline standoffson wireline cablemay minimize wireline cablecontact over a selected zone(s) of an open-hole section. Wireline standoffsmay be installed on wireline cable, for example, to either straddle known permeable zones where differential sticking is a risk (e.g., eliminating cable contact 100%), or they may be placed at regular intervals along wireline cableto minimize key-seating, taking into account, for example, the dogleg severity of borehole. For boreholeswith higher dogleg severity, the spacing between wireline standoffson wireline cablemay be reduced. In certain embodiments, the spacing of wireline standoffson wireline cablemay be from about 10 feet to more than about 175 feet, alternatively from about 10 feet to about 175 feet, and alternatively from about 25 feet to about 175 feet. Such spacing may be dependent on the requirements for the particular boreholebeing logged. In an embodiment, the spacing of wireline standoffson wireline cablemay be from about 25 feet to about 175 feet. In some embodiments in casing in a pure vertical hole, the spacing of wireline standoffson wireline cablemay be from about 200 feet to about 250 feet.

illustrate an embodiment of a generic logging operation that includes a plurality of wireline standoffscoupled to wireline cable. As illustrated, a plurality of wireline standoffsmay be clamped onto wireline cable. Wireline cablemay be, for example, stored on wireline drumand spooled into the well by a winch driver and logging engineer in logging unit. In the illustrated embodiment, logging unitis fixed to the drilling rig or platform, and wireline cableis deployed through the derrick via two or three sheaves,to the maximum depth of the well. Boreholemay have a cased-hole sectionand an open-hole section. As illustrated, wireline standoffsmay be installed on wirelinein open-hole section. A logging toolmay be connected to the lower end of wireline cableto take, for example, the petro-physical measurements or fluid or rock samples in open-hole sectionof borehole. The number of wireline standoffs, and their positions on wireline cablemay be determined by a number of factors, including for example, the length of open-hole section, the location of sticky, permeable, or depleted zones, and the overall trajectory of the well, which may be deviated or directional in nature.is a close-up view illustrating attachment of wireline standoffto wireline cabletaken along circle. In the illustration of, wireline standoffmay be seen in relation to wireline cable, borehole wall, and borehole.

illustrates an embodiment of one of the opposing assemblies. As illustrated, assemblyincludes half shellwith cable insertdisposed therein. In an embodiment, half shellincludes front portion, rear portionand middle portionthat interconnects front portionand rear portion. In the illustrated embodiment, front portionand rear portionare each in the shape of a conic section with middle portionbeing generally cylindrical in shape. In the illustrated embodiment, half shellfurther includes holesthrough which fasteners (e.g. boltsshown on) may be inserted that secure half shellsto one another clamping cable insertsonto wireline cable. Opposing assemblymay further contain finsthat extend along the length or a portion of the length thereof. As illustrated, each of finsmay in the shape of an arch that spans across at least a portion of middle portion. Accordingly, there may be a gapbetween finsand middle portionwith either end of finsattached to half shell. In addition, finsmay be spaced around middle portionso that there is a gapbetween each fin.

illustrates an embodiment of opposing assembly. In the embodiment illustrated, half shellfurther includes dowel pinssized to fit into corresponding holes in other half shell(not illustrated in). In one particular embodiment, half shellincludes four dowel pins. In certain embodiments, dowel pins, in conjunction with bolts(shown, e.g., on), may, for example, couple half shellstogether. As previously mentioned, dowel pinsmay assist wireline standoffin resisting shear stresses.

illustrate exploded views of embodiments of wireline standoff. As illustrated, wireline standoffincludes opposing assembliesthat each comprises half shell, cable insert, and a plurality of fins. In the embodiment illustrated in, dowel pinsare included in one of half shellsfor insertion into corresponding holes (not illustrated) in the other half shell. As illustrated, each of cable insertsmay be in the general shape of a hollow, half cylinder. Each of cable insertsmay have first flanged endand second flanged end. As illustrated, first flanged endand second flanged endmay be tapered. In an embodiment, when assembled, first flanged endand second flanged endeach may extend beyond half shellsthat encase at least a portion of cable inserts. In embodiments, cable insert flangesmay be disposed over at least a portion of middle portionof each cable insert. In an embodiment, cable insert flangesare integral with cable inserts. In an embodiment, cable insert flangesare not integral with cable inserts. Anti-rotation spigotmay be formed in one or more of cable insert flanges. As illustrated, each of half shellsincludes a through passagewayhaving an inner wall. In general, through passagewayin each half shellis sized to receive a corresponding cable insert. In one embodiment, inner wallof through passagewayin each of half shellsmay have a cut outthat receives corresponding cable insert flangepreventing axial movement of wireline standoffwhen installed. In addition, protrusionmay extend from the inner wall in cut outwith protrusionbeing sized to fit into anti-rotation spigotto prevent rotation of wireline standoff. In this manner, cable insert flangesand anti-rotation spigotmay lock half shellsand cable inserts.

illustrates an embodiment of cable insert. As illustrated, each cable insertincludes first flanged end, second flanged end, and middle portion. As further illustrated, cable insertincludes cable insert flangedisposed over middle portionof cable insert. In the illustrated embodiment, cable insert flangeseach include anti-rotation spigot. In one embodiment, fasteners, such as small cap head screws, may be used to retain cable insertsin half shells. As illustrated, fastenersmay be received by openingsin cable insert flange. For example, through holes may be formed in each half shellthat extend through the wall of cutoutin through passagewayfor receiving fasteners.

illustrates a cross section of an embodiment of wireline standoffinstalled on wireline cable. As illustrated, wireline standoffincludes opposing assembliesthat each comprise half shell, cable insert, and a plurality of fins. Half shellseach comprise holesthat may be used, for example, to connect wireline standoffto a lanyard during installation. In the illustrated embodiment, cable insertis in contact with wireline cable. As further illustrated, each cable insertincludes first flanged end, second flanged end, and middle portionwith cable insert flangesdisposed over middle portion. In the illustrated embodiment, first flanged endand second flanged endeach extend beyond half shells. As illustrated, cable insert flangesmay fit into corresponding cut outsin half shells. In one embodiment, protrusionin cutoutsfits into anti-rotation spigotof cable insert flanges. As further illustrated, fastenersextend through half shellsand into cable inserts.

Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations may be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Although individual embodiments are discussed, the invention covers all combinations of all those embodiments.