GB2154001A - Line depth measurement apparatus for subterranean wells - Google Patents

Abstract

Apparatus for continuously measuring the movement of a line L or other rod-like member insertable into a subterranean well comprises a base 11 attached to a lubricator assembly 4 or other rigid structure, a primary support 15 carrying a guide roller 31, a secondary support 20 carrying a measuring roller, resilient means 24 for holding the measuring roller against the line, means for counting the rotations of the measuring roller eg permanent magnets 33 and a pick- off 35, and a connection between the base 11 and the support 15 comprising an elongated flexible element 13 which allows lateral movement of the supports 15, 20 relative to the base 11. <IMAGE>

Description

SPECIFICATION Line depth measurement apparatus for subterranean wells In the completion and workover of subterranean oil or gas wells, it is common to employ wireline supported tools. It is very important to know the depth at which the tool is positioned and this has customarily been accomplished by measuring the length of wireline or sandline run into the well.

Well completion operations are generally accomplished by drilling rigs which are well equipped for continuously measuring the length of a wireline that is run into the well, and thus indicate the depth of the tool. In fact, most drilling rigs are equipped with permanent apparatus adjacent to the cable reel on which the wireline supply is stored.

Hand held depthometers are also available.

Accordingly, there is no problem in training the wireline over a measuring pulley and maintaining the path of the wireline as it passes over the pulley in a substantially constant position, thereby eliminating any inadvertent slippage of the wireline relative to the pulley.

In workover operations, however, such luxuries are not available or affordable. A lubricator assemblage is generally connected to the top of the Christmas tree mounted on the well head and the tool carrying wireline or sandline is fed through the lubricator by a portable crane or derrick. Since there are literally hundreds of designs of portable cranes and derricks, it is not surprising that a wireline depth measuring device has not heretofore been developed which is applicable to any type of workover rig. Furthermore, it must be remembered that any wireline measuring device must be assembled in cooperative relationship to the wireline in the field and hence, is subject to very rough handling.There is, therefore, a definite need for a wireline depth measuring apparatus which may be attachable in the field to any type of workover rig, preferably utilising a lubricator assemblage and capable of supplying highly accurate depth measurements of tools that are run into the well on a wireline or sand line by the workover rig.

According to the invention apparatus for continuously measuring the movement along a path of a rod-like member insertable into a subterranean well comprises a base attachable to a rigid structure adjacent the path, a measuring roller support straddling the path and disposed in spaced relation along the path relative to the base, a measuring roller journalled in the support, resilient means for holding the periphery of the measuring roller in engagement with the rod-like member to rotate the measuring roller, means responsive to the rotation of the roller for indicating movement of the rod-like member as it passes the measuring roller, and connecting means by which the said support is connected with the base and that include an elongated flexible element for absorbing lateral deviations of the rod-like member relative to the rigid structure.

The rod-like member is generally a wire or line carrying a tool, preferably a sand line that can be inserted in a workover rig in to a subterranean well. preferably the rigid structure is a lubricator assembly. The apparatus conveniently is used to indicate the length of the wire, and thus the depth of the tool carried by the wire. The means responsive to the rotation of the roller for indicating movement of the wire or other rod-like member generally comprises means for counting the rotations of the roller.

The invention therefore can provide a wireline or sandline depth measuring device which is conveniently attachable to a rigid well structure adjacent to. or surrounding the path of the wireline as it is run into the well. Preferably, the depth measuring apparatus is mounted on the top portions of a lubricator assembly. A preferred location for the depth measuring apparatus is on the oil saver device which is conventionally provided on the top of the lubricator assemblage to wipe oil adhering to the line as it is withdrawn from the well and direct the wiped oil through a pipe to a storage tank.

The line depth measuring apparatus may comprise a base element which is attachable to the top portion of the lubricator assemblage and a pulley mounting portion which is axially spaced from the base portion in the direction of the path of the wireline. The pulley mounting portion may comprise two brackets which are pivotally interconnected, and at least one of the brackets straddles the path of the line.

Adjustable springs may be provided between the pivoted brackets to urge both of the brackets toward the line. Each bracket may carry at least one pulley. One of the pulleys functions as a guide pulley and is provided with a notched periphery to engage the line.

Another pulley functions as a measuring pulley or roller and has a cylindrical surface engagable with the wireline or sandline. The measuring pulley or roller may carry means for counting its rotations, such as one or more permanent magnets mounted on the measuring pulley to move in a rotational path, proximity switches, or Hall effect elements. Conventional pickup coils can be mounted on the bracket supporting the measuring pulley and the signals generated in such pickup coils are transmitted to a conventional logic circuit for converting the signals received by the passage of the permanent magnets past the pickup coils into indications that correspond to the depth of the tool being run into the well by the line. Proximity switches or Hall effect elements can function in a similar conventional manner.

Since it is known that the wireline or sandline tends to randomly laterally shift from its normally vertical axial path into the lubricator assemblage, an elongated, laterally unconstrained flexible element is provided for mounting the pulley support brackets to the base which is rigidly secured to the top portion of the lubricator assembly. Thus, lateral deviations of the wireline can be accommodated by this flexible mounting of the pulley support brackets and the possibility of error due to inadvertent slippage of the measuring pulley relative to the wireline is greatly diminished. The additional flexibility also protects the device from damage during mounting or handling.

Further advantages of the invention will be readily apparent to those skilled in the art from the following detailed description, taken in conjunction with the annexed sheets of drawings on which is shown a preferred embodiment of the invention.

Figure 1 is a schematic elevational view of a sandline supported by a derrick and entering a lubricator assemblage for workover operations in a subterranean well to which the lubricator assemblage is connected.

Figure 2 is an enlarged scale, vertical elevational view of the line depth measuring appartus embodying this invention which is mounted on the top portion of the lubricator assemblage of Figure 1.

Figure 3 is a sectional view taken on the plane 3-3 of Figure 2.

Referring to Figure 1, there is schematically illustrated a subterranean well 1 having a conventional Christmas tree 2 assembled at the surface of the well head. A conventional lubricator assemblage 3 extends upwardly from the Christmas tree 2 and a conventional oil saver device 4 is mounted on the top portions of the lubricator assemblage.

While the invention may be utilised with any type of wireline or sandline and can be used to measure the run-in depth of wireline tools during the completion of a well, it will be described and illustrated in conjunction with the reworking of a well by running in appropriate tools on a sandline L. Sandline L is supported and trained over a pulley (not shown) conventionally supported on the top of a portable derrick 5. Obviously, any type of portable crane may be utilised in place of the portable derrick 5. A line depth measuring apparatus 10 embodying this invention is then supported on the top of the lubricator assemblage 3, preferably by having a bracket or base portion 11 bolted to a cylindrical portion 4a of the oil saver device 4.

Referring now to Figures 2 and 3, it will be seen that the depth measuring device 10 comprises an upstanding tubular post 1 2 which is bolted to the outer end of the base or bracket portion 11. The tubular post portion 1 2 supports an upstanding, resiliently deformable column 1 3 which is here shown as a tightly wound compression spring, but may comprise a solid column of suitable resilient material.The important factor is that the resiliently deformable column 1 3 is laterally restrained and can defiect in any direction about the vertical axis of the support post 1 2. In another embodiment of the invention the sleeves 1 2 and 1 6 are in abutment and the spring 1 3 does not carry the weight of the upper assembly, however, lateral deflection is not significantly restrained by the abutting sieeves.

A primary pulley bracket 1 5 is provided with a depending hollow post or sleeve 1 6 which is bolted to the upper end of the resiliently deformable post 13. Primary pulley bracket 1 5 comprises two spaced apart paral lel plate portions 1 5a and 15b bolted to opposite sides of depending post 1 6 by bolts 15c. A secondary pulley bracket 20 having arm portions 21 and 22 straddling the path of the wireline or sandline L is provided, and is pivotally mounted to the primary bracket 1 5 by a pivot pin 1 7. Secondary pulley bracket 20 comprises two parallel plate portions 20a and 20b secured by bolts 20c and spacer tubes 20d.A pair of spring assemblies 23 and 24 are respectively mounted on each side of brackets 1 5 and 20. In the embodiment depicted herein, assemblies 23 and 24 provide an adjustable, resilient bias of the secondary bracket 20 toward the primary bracket 1 5. Tensioning devices 23 and 24 could, however, be replaced by conventional tensile coil springs.

The adjustable tensioning devices 23 and 24 are of identical configuration and comprise a yoke-shaped stamping 23a and 24a which has the single end thereof pivotally secured to a mounting pin or bolt 21a and 22a to the medial portions of the bracket arms 21 and 22 respectively. The other ends of the adjustable spring elements 23 and 24 are respectively mounted on adjustment screws 25 and 26 and are respectively journalled in bearing lugs 1 8 secured to bracket plates 20a and 20b. Screws 25 and 26 respectively thread through square nut elements 29 provided in the yoke-shaped portions 23a and 24a of the spring mounting yokes 27 and 28 for conveniently effecting the adjustment of the screws relative to the square nut 29, thus compressing springs 29a which are respectively mounted between such nuts and the outer closed ends of the yoke portions 23a and 24a.

Cable engaging pulleys 30 and 31 are respectively journalled on the secondary bracket 20 and the primary bracket 1 5 by shafts 20f and 15f. One pulley, for example, pulley 30, constitutes the line depth measuring pulley and is provided with a cylindrical external surface 30a. Another pulley 31 is provided with a notched, peripheral external surface 31a and engages the wireline or sandline L at two points to thus centralise the line L with respect to the cylindrical surface 30a of the measuring pulley or roller 30. An additional guide pulley identical to pulley 31 (not shown) can also be provided on the opposite side of the measuring roller.

From the foregoing description, it will be apparent that the adjustable bias imparted by the adjustable spring assemblages 23 and 24 effect a gripping engagement of the wireline or sandline L between the notched peripheral surface 31a of the guide pulley 31 and the cylindrical surface 30a of the measuring pulley 30.

Measuring pulley 30 is provided with electronic means for counting the revolutions of the measuring pulley as schematically indicated by two peripheral targets comprising spaced permanent magnets 33 which are suitably mounted adjacent the periphery of the measuring wheel 30 and thus move in a rotational path. A position sensor pickup coil or sensing device 35 is provided adjacent the rotational path of the targets 33 and is of conventional construction designed to produce signals each time that one of the permanent magnets 33 passes by the pickup coil 35.

Such signals are transmitted by appropriate electric conductors 35a to conventional circuitry (not shown) provided on ground level and including a logic circuit which converts the pulsating signals induced by the permanent magnets 33 into indications of the length of the wireline or sandline L passing over the periphery of the measuring pulley 30. Other conventional sensor means, such as Hall elements, can be used to detect rotation.

An important feature of the above described apparatus is the fact that the measuring apparatus 10 is not adversely affected by a substantial lateral deviation of the wireline or sandline L from a true vertical position. Any such lateral deviation, in any direction, will be absorbed by the flexible, laterally unrestrained, support element 1 3 and thus the frictional engagement between the wireline or sandline L and the cylindrical surface 30a of the measuring pulley 30 is undisturbed. In fact, it is common in workover operations to assemble the desired tool on the sandline L within the lubricator assembly 3 while the lubricator assembly is in a horizontal position on the ground, and then elevate the lubricator assembly to the illustrated vertical position by raising the upper end of the lubricator assembly by the sandline L.This obviously would impose a substantial force on the measuring appartus 10 and cause damage thereto if it were not resiliently supported by the laterally unrestrained flexible support element 13.

Those skilled in the art will recognise that the aforedescribed apparatus provides a simple, economical but yet extremely reliable wireline or sandline depth measuring instrument which is attachable to any well for completion or workover purposes by securement to the top of a lubricator assemblage or to any other member which is disposed laterally adjacent to the path of the wireline L.

The depth measuring indications are not affected by lateral deflections of the wireline or sand line relative to the entry portion of the well. Moreover, the apparatus can be conveniently mounted on the top of any lubricator assembly and thus is ready for usage without requiring the fabrication of special mounting brackets to mount the same on a boom or derrick.

Although the invention has been described in terms of specified embodiments which are set forth in detail, it should be understood that this is by illustration only since alternative embodiments and operating techniques will be apparent to those skilled in the art in view of the disclosure. For example, the apparatus described herein can be employed to measure the length of other rod-like elements, such as coil tubing, insertable into a subterranean well in addition to measuring a sandline or wireline. Furthermore, it will be appreciated that the apparatus can be easily adapted to measure speed as well as distance as the tubular member is inserted or withdrawn from the well.

Claims (10)

1. Apparatus for continuously measuring the movement along a path of a rod-like member insertable into a subterranean well and comprising a base attachable to a rigid structure adjacent the path, a measuring roller support straddling the path and disposed in spaced relation along the path relative to the base, a measuring roller journalled in the support, resilient means for holding the periphery of the measuring roller in engagement with the rod-like member to rotate the measuring roller, means responsive to the rotation of the roller for indicating movement of the rod-like member as it passes the measuring roller, and connecting means by which the said support is connected with the base and that include an elongated flexible element for absorbing lateral deviations of the rod-like member relative to the rigid structure.

2. Apparatus according to claim 1 in which the rod-like member is a wire carrying a tool and the measuring roller is constructed to indicate the length of wire that has passed the roller, the apparatus thereby continuously measuring the depth of the tool.

3. Apparatus according to claim 1 or claim 2 in which the means responsive to the rotation of the roller comprise means for counting the rotations of the roller to indicate the length of rod-like member passing the roller.

4. Apparatus according to any preceding claim in which the means responsive to the rotation of the roller comprise at least one magnet mounted on the measuring roller to move in a rotational path and at least one pick-up coil mounted on the support adjacent the rotational path of the magnet.

5. Apparatus according to any preceding claim in which the elongated flexible element comprises a laterally unconstrained compression spring.

6. Apparatus according to any preceding claim in which the resilient means holding the periphery of the measuring roller in engagement with the rod-like member comprises at least one guide pulley journalled on the opposite side of the rod-like member relative to the measuring roller and adjustable resilient means urging the roller and pulley into engagement with the rod-like member.

7. Apparatus according to any preceding claim comprising a first pulley support bracket disposed in axially spaced relation to the base, a first pulley journalled in the first pulley support bracket and engageable with the rod- like member, a second roller support bracket having arm portions straddling the path and pivotally mounted on the first pulley support bracket, and a second roller journalled in the second roller support bracket and engageable with the rod-like member in diametrically opposed relation to the first pulley, and in which one of the pulley and the roller serve as the measuring roller and in which the resilient means urge the pulley brackets towards the rod-like member thereby maintaining frictional engagement of the rollers with the rod-like member.

8. Apparatus according to any preceding claim attached to a rigid structure.

9. Apparatus according to claim 8 in which the rigid structure is the lubricator assembly of a workover rig and the rod-like member is a sand line.

10. Apparatus according to claim 1 substantially as herein described with reference to any of the accompanying drawings.