Pipe wiper

April 3, 1956

2,740,480

H. J. COX

PIPE WIPER

Filed April 28, 1954

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INVENTOR.

Howard J. Cox

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2,740,480

Patented Apr. 3, 1956

United States Patent Office

2,740,480

PIPE WIPER

Howard J. Cox, Oklahoma City, Okla.

Application April 28,1954, Serial No. 426,206

Claims. (Cl. 166—170)

This invention relates to pipe wipers and more particularly to a structure for wiping the inside of a drill pipe or the like used in drilling wells as said drill pipe is removed from a well being drilled.

It is now common practice in the drilling of boreholes for oil and the like to use various kinds and specific gravities of drilling mud which is circulated in the borehole and tools during the drilling operations. This mud contains expensive chemicals including mild acids and caustics to provide better non-caving borehole conditions, better cooling of the drilling bit, and better control over gas blowouts, which could result in injury to the drilling crew and damage to equipment. A certain amount of this drilling mud always escapes on the rig floor when the drill pipe is being pulled from the borehole to change bits, causing a wet, slick floor condition where the crew is working and making up or breaking out the drill pipe in running in or out of the borehole. In freezing temperatures this wet floor freezes, making it even more slippery and dangerous for the drilling crew. While several types of outside drill pipe wipers are presently in use in the drilling industry to help solve this hazardous and wasteful problem, the inside of the drill pipe never drains completely due to the heavy mud weights and as a result the mud adhering to the inside of the drill pipe drips and runs onto the derrick floor as the pipe is being set back in the derrick and stored therein while the remainder of the drill pipe is being pulled from the borehole and is again run into the borehole. Also, the wet condition on the inside of the drill pipe due to the mud adhering thereto causes rust and corrosion to form in the inside of the pipe while not in use.

The objects of the present invention are to provide a pipe wiper for removing drilling mud from the inside of drill pipe and thereby keep the inside of the drill pipe clean and dry as it is withdrawn from the borehole whereby the above mentioned hazardous and wasteful condition is completely overcome; to provide a pipe wiper for the inside of drill pipe that combines a buoyant structure adapted to float in drilling mud with flexible wiping members supported on the buoyant member and extending above the level of the drilling mud whereby as the drill pipe is removed from a well the wiper remains at substantially the same elevation to wipe the inside of said pipe; to provide such a pipe wiper with an air chamber for buoyancy with a weighted lower end of suitable proportions relative to the specific gravity of the drilling mud whereby the air chamber provides buoyancy to retain the wiping members above the level of the mud and the weighted lower end prevents the friction between the flexible wiping members and pipe from raising the pipe wiper from the drilling mud as the pipe is removed from the borehole; to provide such a pipe wiper structure that will permit bypass of drilling fluid should it become necessary to circulate drilling mud in the borehole at any time while the pipe wiper is in service; and to provide a pipe wiper for the inside of drill pipe that is economical to manufacture, easily assembled and efficient in use for cleaning and drying the inside of drill pipe as it is being removed from a borehole.

In accomplishing these and other objects of the present invention I have provided improved details of structure the preferred forms of which are illustrated in the accompanying drawings, wherein:

Fig. 1 is an elevational view of the pipe wiper inside of a drill pipe in a borehole.

Fig. 2 is a vertical sectional view through the pipe wiper.

Fig. 3 is a transverse sectional view through the pipe wiper on the fine 3—3, Fig. 2.

Fig. 4 is a transverse sectional view through the pipe wiper air chamber on the line 4—4, Fig. 2.

Fig. 5 is a transverse sectional view through the weighted end of the pipe wiper on the line 5—5, Fig. 2.

Referring more in detail to the drawings:

designates a pipe wiper embodying the features of the present invention and adapted to wipe the bore 2 of drill pipe 3 as it is removed from a borehole 4. In the rotary drilling of oil wells and the like it is common practice to have a drill bit on the lower end of one or more drill collars with the uppermost collar connected to the lowermost joint of a string of drill pipe sections 3, the drill pipe sections being connected together by threaded joints as at 5. The upper section of the drill pipe is connected to a Kelly rod that extends through a turntable 6 suitably mounted in a derrick floor to rotate the Kelly rod and drill pipe connected thereto. It is common practice to pump drilling mud downwardly through the Kelly rod, drill pipe sections, drill collars and through the bit, the mud flowing upwardly in the borehole around the drill pipe and then through a suitable channel 7 to a collecting basin from which it is pumped in the circulation of the drilling mud. When it is necessary to change the bits or otherwise service the borehole the drill pipe is removed therefrom, the drill pipe being pulled upwardly through the turntable by suitable elevators and then the main string held while the sections are disconnected. During such operation the drilling mud tends to remain at substantially the same level, as at 8, both inside and outside the drill pipe.

. The pipe wiper 1 is adapted to be inserted in the drill pipe bore 2 when the Kelly rod is removed from the uppermost section of the drill pipe. The pipe wiper 1 has a weight portion 9 at the lower end of a buoyant chamber 10 and a plurality of flexible wiping members 11 suitably supported above the buoyant chamber 10. In the illustrated structure there is a tubular shell 12 of smaller diameter than the smallest portion of the bore through the drill pipe section. The lower end of the shell is closed by a plug 13 of suitable metal or the like to provide sufficient weight to cooperate with the buoyant chamber 10 whereby the entire structure will float in the drilling mud and the weight will overcome the friction between the wiping members 11 and the inside of the walls of the drill pipe. The plug 13 has a threaded upper portion 14 which is screwed into the lower portion of the shell with a portion of the plug extending from the shell having a tapered or curved contour defining a substantially pointed lower end 15. A plurality of longitudinal grooves are spaced around the periphery of the lower end of the plug 13 to serve as bypasses for the drilling mud as later described.

The upper end of the shell 12 is secured to a closure member 17 provided with a stem IS extending therefrom substantially coaxially of the shell 12. In the illustrated structure the closure 17 is in the form of a pipe reducer bushing, having an externally threaded portion 19 threaded into the upper end of the shell 12 with an internally threaded boss 20 extending upwardly therefrom.

2,740,480 member having a relatively heavy weighted tapered end, said chamber member being smaller in external diameter than the smallest bore of drill pipe in which the wiper is to be used, an extension member smaller in diameter than the buoyant chamber member arranged axially of said chamber member and extending therefrom at the end opposite the weighted tapered end of the buoyant chamber, a plurality of flexible wiping members sleeved on the extension member, said wiping members being of suitable size with slits in the peripheral portion thereof whereby said peripheral portion resiliently and wipingly engages the interior of a drill pipe, means spacing the flexible wiping members on the extension member, and means on the extension member for retaining the wiping members and spacing means against axial movement on the extension, said buoyant chamber and weighted end being proportioned whereby the weight overcomes the friction between the wiping members and drill pipe to effect gravitational movement thereof downwardly in the drill pipe and the buoyancy of the chamber member in the drilling fluids causes said chamber member to float and maintain the wiping members above the fluid level.

2. A pipe wiper for wiping mud and drilling fluids from the inside of well drill pipe as said pipe is removed from a 25 borehole comprising, an elongate substantially cylindrical shell, a plug member secured to one end of the shell in closing relation thereto, a substantially conical extension on said plug member having longitudinal grooves in the exterior thereof, an extension of smaller external diam30 eter than the shell arranged at the other end of said shell in closing relation thereto to define a buoyant chamber in the shell, a plurality of spaced flexible wiping members sleeved on the extension, spacing means sleeved on the extension between the wiping members to maintain said 35 wiping members in spaced relation, and means on the extension for retaining the wiping members and spacers against axial movement on the extension, said wiping members being of such size that the peripheral portions thereof resiliently and wipingly engage the interior,of the drill pipe, said shell, extension and plug being proportioned whereby the plug forms a weighted end on the shell and the weight thereof overcomes the friction between the wiping members and drill pipe to effect gravitational movement thereof downwardly in the drill pipe and 45 the buoyancy of the chamber defined by the shell causes the pipe wiper to float in the drilling fluids with the wiping members above the fluid level.

3. A pipe wiper for wiping mud and drilling fluids from the inside of well drill pipe as said pipe is removed from 50 a borehole comprising, an elongate substantially cylindrical shell, a plug member secured to one end of the shell in closing relation thereto, a substantially conical extension on said plug member having longitudinal grooves on the exterior thereof, a tubular extension of smaller 55 external diameter than the shell arranged at the other end of said shell, means closing the end of the tubular extension remotely from the shell, means connecting the adjacent ends of the shell and tubular extension whereby the shell and extension cooperate to define a buoyant 60 chamber, a plurality of spaced flexible wiping members sleeved on the tubular extension, and means on the tubular extension for retaining the wiping members against axial movement on the tubular extension, said wiping members ana men me ^{being of such size that the} peripheral portions thereof [ _{whsn the} 65 resiliently and wipingly engage the interior of the drill pipe, said shell, tubular member and plug being proportioned whereby the plug forms a weighted end on the shell and the weight thereof overcomes the friction between the wiping members and drill pipe to effect gravi'f 70 tational movement thereof downwardly in the drill pipe and the buoyancy Of the chamber defined by the shell causes the pipe wiper to float in the drilling fluids with the wiping members above the fluid level.

4. A pipe wiper for wiping mud and drilling fluids from ⁷⁵ the inside of well drill pipe as said pipe is removed from

The.shank 18 is preferably tubular for lightness in weight and has a lower end threaded into the internally threaded boss 20 of the reducer bushing or closure 17. The upper end of the tubular shank 18 is suitably closed as by a pipe plug 21. While the closures of the air chamber formed by the shell 12 and tubular shank 18 are provided with threaded connections it is obvious welding or other suitable connections may be used that will make water tight joints.

The wiping members 11 are preferably of neoprene or 1 other suitable flexible material and are preferably circular disks with bores 22 therein for sleeving the disks on the shank 18. Suitable spacers 23 are sleeved on the shank between the flexible wiping disks to provide suitable spacing therebetween. The wiping disks and spacers are held on the shank 18 by a nut 24 threaded on the upper end of the shank 18, said nut being tightened to prevent any endwise movement of the wiping members or spacers. The wiping disks are preferably provided with a plurality of spaced notches or cuts 25 arranged around the : periphery .thereof to facilitate the bending of the edges of the wiping disks whereby they will conform to the interior or bore of the drill pipe and provide proper wiping contact therewith. The wiping disks may be made in various thicknesses and sizes for best wiping action on various size drill pipe and also may be any suitable number whereby the wiping will clean the bore of the drill pipe.

In using a pipe wiper constructed and assembled as described, the Kelly rod is removed from the uppermost sec tiOn,.of drill pipe and the pipe wiper inserted into the bore of said drill pipe with the weighted end 9 inserted foremost in said drill pipe. The weight of the plug and •sheik will cause the pipe wiper assembly to move downwardly in . the drill pipe and into the drilling mud and then the buolancy provided by the buoyant chamber 10 will cause the structure to float in the drilling mud with the pipe wipers 11 above the level of said mud, as illustrated in Fig. 1. Then the drill pipe is pulled from the borehole in the customaiy manner. As the drill pipe is .elevated the pipe wiping apparatus remains substantially in the same position relative to the level of the drilling mud, the wipers wiping the drilling mud from the bore of lire drill pipe as said drill pipe is elevated.

In the event the drill pipe should become stuck or for other reason it is necessary to circulate the drilling mud in the drill pipe and borehole, the discharge of the mud pump is connected to the drill pipe and the mud pumped downwardly therein. The pump pressure acting on the pipe wiper will force said pipe wiper downwardly of the drill pipe until the buoyancy of the pipe wiper in the drilling mud is such that the pump pressure can force the drilling mud by the pipe wipers 11. However, in most instances the pump pressure will force the pipe wiper assembly downwardly in the drill pipe until the plug 13 engages the bore of the uppermost drill collar, which bore is substantially smaller than the bore of the drill pipe. While the plug 13 would tend to close the bore in the drill collar, the grooves 16 provide passages for the drilling mud to permit the circulation of the drilling mud in the borehole. After the circulation of the drilling mud is stopped and the pump disconnected the buoyancy of the pipe wiper structure will cause it to rise to the surface of the drilling mud in the drill pipe and then the drill pipe pulling operations may be resumed. ,....... .— lowermost section of the drill pipe is disconnected from the uppermost drill collar the pipe wiper is removed from the lower end of said lowermost drill pipe section.

It is believed obvious that I have provided a simple, efficient pipe wiper structure for cleaning the inside of drill pipe as it is removed from boreholes.