DE1233344B - Hydraulic compensation transition for drill rods - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

E21b

German class: 5 a - 17/06

Number: 1233 344

File number: J 28279 VI a / 5 a

Filing date: June 3, 1965

Opened on: February 2, 1967

The invention relates to a hydraulic compensation transition for drill rods with an inner, connected to the drill string, hollow mandrel and an outer, the drilling tool supporting Casing tube, which is telescopically movable lengthways to the mandrel, but connected to it in a torsionally rigid manner is.

As is known, a drill string normally includes a drill bit or a fishing tool, a number of drill bit attached drill collars and one connected to the drill collars Drill string. When drilling, it is often desirable to use a leveling transition, which in this case consists of upper and lower, telescopically nested sections and usually its place between the drill pipe and the drill collars or within the Has drill collar; one or more drill collars, as required, can be be attached above the equalization transition. The drilling torque is passed through the drill pipe a turntable, a power flush head or the like. Imposed and through the entire compensation transition and drill collar set transferred to the base of the drill string where the drill bit or the Fishing tool is attached to the hole into the earth or the fishing work with the help of Liquid or gas carry down inside the string and out of the nozzles in the drill bit is pumped out. This flushing medium (air, gas, drilling mud or the like.) Is down through the Inside the drill string pumped down at high pressure, passes through the nozzles in the drill bit or the safety gear and returns upwards through the annulus at approximately ambient pressure between the drill string and the inner wall of the borehole. It is also possible the reverse To use circulatory technology by pumping such a flushing medium down into the annulus; the mud then flows through the nozzles in the drill bit into the interior of the drill string and returns to the surface within the drill string.

Because the mud fluid is pumped down the drill string under pressure and exits the drill string through nozzles in the drill bit to return to the surface at atmospheric pressure, there is a pressure differential between the inside of the string and the outside. Differential pressure also exists when the reverse circuit is used; for the purpose, however, of the desired construction and operation of the present invention to be-Hydraulic compensation transition for
Drill pipe

Applicant:
5

Joy Manufacturing Company,

Pittsburgh, Pa. (V. St. A.)
Representative:

ίο Dipl.-Ing. M. Licht, Dr. R. Schmidt,
Dipl.-Wirtsch.-Ing. A. Hansmann
and DipL-Phys. S. Herrmann, patent attorneys,
Munich 2, Theresienstr. 33

Named as inventor:
Charles Drovil Crickmer,
Houston, Tex. (V. St. A.)

Claimed priority:

V. St. v. America June 5, 1964 (372 856)

write, the flushing fluid should be viewed as if it were being pumped down within the drill string will. The equalization transition of the present construction, the one inside with the drill string Connection is influenced by the above-mentioned diflerential pressure and works thanks to the sealing Arrangement between the telescopic sections in the manner of a hydraulic jack. For example, if a differential pressure between the inside and the outside of such a balance transition is larger on the inside, it gives rise to expansion (increase in length) and to application a downward force on the drill bit equal to the internal cross-sectional area of the telescopic Sections times the differential pressure; in the following this will be referred to as the differential pressure expansion force explained. Such a differential pressure expansion force that seeks to reduce the Lengthening the balance transition also places an upward reaction force on the bottom of the drill string which builds up a longitudinal compressive stress in this. Such tension is extreme undesirable because it tends to warp or bend the drill pipe. Warped or bent Because of its "crankshaft-like" shape, drill pipe is quickly abraded if it breaks rotates in the borehole. This condition also leads to high levels

709 507/53

3 4

Bending stresses in the drill string and especially in the one another to slide in one direction and

Connectors or connections and often has to change the length of this drill string part; the

Failure of the material. telescopic sections close an axially

Since it is important that the chamber running downwards is sandwiched between shoulders that are attached to the

the force on the drill bit remains constant (one of the pieces is equal to 5; a blocking ring underneath

the weight of the drill bit and the proportion of the chamber divided into upper and lower chamber parts,

attached collars), the purpose of use is attached to one of the pieces and stands with

a compensation transition, the transfer to the other of the pieces in a sliding sealing

any part by weight of the drill string on the agitator; Passages connect the upper and

Drill bits during normal drilling work to io lower chamber parts with the inner and outer

impede. The above-described differential pressure chambers of the drill string, in such a way,

Expansion force increases the pressure differential across the bit that tends towards it

applied force; this is undesirable in that it acts to move the telescopic sections into one of the

a force on the bit causing the direction you just requested to slide in the opposite direction

Exceeds amount, damage to drill bit or leave in 15.

consequent increase in drilling progress and the associated one feature of the invention it also corresponds to the Excessive torque required to twist the differential pressure for expanding movement out of the drill string can cause; the end result are set cross-sectional areas essentially the same then fishing work with the associated time and cross-sectional area of the telescopic parts Loss of money. 20, which correspond to the differential pressure for

Compensation transitions according to the prior art is exposed to pulling movement.

fulfill their purpose under certain conditions; The invention and its advantages will be

however, when conditions occur such as B. Pay more attention to the following description and drawing

Pump pressures, nozzle bits, deeper boreholes are easier to see.

and drilling work from the floating sea craft 25 Figs. la, lb, lc and ld illustrate

out, the problem of differential pressure, composed of a longitudinal center section, pushes itself through

expansion of the equalization transition to. an inventive balance transfer. the

According to the invention, this object is achieved by the representation produced by assembling the

an annular chamber between the mandrel and the casing- F i g. 1 a, 1 b, 1 c and 1 d when covering line AA

tube, holes for admitting the flushing medium from 30 with the line A'-A ', ie Fig. la above and

the hollow mandrel into the chamber, one below Fig. 1b below it, and in a similar manner

of the bores on the mandrel clamped and sealed when the line BB is aligned with the line B'-B ' and

tend to cooperate with the chamber wall when the line CC coincides with the line CC.

Ring which divides the chamber into an upper section F i g. Fig. 2 is a cross-sectional view substantially on

and subdivided a lower portion, each 35 of the line 2-2 of Fig. Ic taken and the through

at its end is seen through the direction indicated by the arrows narrowed at this point.

Inside diameter of the jacket pipe are limited, the drawings represent an oil-sealed design

wherein the cross-sectional area of the chamber in the upper junction 10 represents, according to the outline

Section is coextensive with a circle, which this invention is constructed and preferred

Diameter equal to the bore of the jacket pipe 40 pattern is illustrated. It should be made clear that

is at the lowest end, and holes in the although the compensation transition 10 is oil-sealed, the

Jacketed pipe, which covers the lower section of the Kam Invention Basics in the same way on

mer with the borehole. transitions without oil seal or with open ones

The present invention solves this problem of spline gears as well as other axially

by creating a leveling transition employing under 45 expandable elements of a drill string

do not leave any circumstances in the manner of a hydraulic one. The equalizing transition 10 takes when it is in

Jack works. The present solution this one drill string is used, usually the

Problem is based on the creation of a ring-represented space. The F i g. 1 a represents the upper

shaped piston cross-section, which is the differential part of the compensation transition 10 and the F i g. 1 d that

pressure is subjected in a manner that represents a force 50 foot end, while the FIG. 1b and 1c top

with the endeavor brings about the compensation or lower intermediate parts of the compensation transition

Shorten transition; this power comes into the 10 illustrate. In the illustration, the

Equilibrium with the difference balance transition described above 10 an elongated, hollow,

compressive expansion force, which strives to the generally cylindrical mandrel 12, which has a stepped,

to extend the crossover. 55 has a cylindrical outer surface. The mandrel 12 runs

According to the invention, a rotary drilling device is designed in such a way downwardly as the through element of FIG. 4 that it contains a piece with telescopically in the part of the compensation transition 10, which at the top contains sections nested in one another; this F i g. 1 a can be seen, up to the part of the equalization forming a component of the drill string and ent- transition 10, which can be seen in the middle of Fig. Id hold on the one hand an elongated hollow piece, which is ^6o . The mandrel 12 can slide longitudinally by being rigidly connected to a drill string, in that it can be enclosed within a longitudinally extending central bore 14 of a casing tube 16 of the hollow piece; this is taken up in transition with that which is offset in the Dar rotation and serves to carry a work position from the middle part of FIG. 1 a stuff; the sliding engagement of these pieces is extended through 65 through FIGS. The head end of the dome 12, which is exposed to the differential pressures with the endeavor, is designed accordingly, the telescopic sections are relative to a drill rod to grasp; this construction

contains in the representation a standardized socket end see the upper middle element 26 and the

17 with a matching internal thread around the mandrel 12. The upper annular space Spigot end engages around a rod length. A 34 has to be connected to the outside of the jacket pipe Part 13 of the dome 12 with a stepped diameter 16 through a plurality of radial bores 37 in the manner immediately below the socket end 17 with full 5 connection that within the annular space 34 of the Diameter is sliding in the central bore 14 pressure is always equal to that of the environment. However Jacket tube 16 added; another part within the annular space 34 and in sliding

18 with a stepped diameter directly in contact with the part 33 of the dome 12 and also the part 13 is located with a suitable sealing packing with the central bore 14 of the jacket tube 16 20 of a known type provided in order for sealing io itself a distributor ring 40, which slides in sealing tang between the mandrel 12 and the jacket tube 16 contact on both the mandrel 12 and the jacket care for. The transition between the full pipe 16 rests in order to equalize pressure within the Diameter of the socket end 17 and the ab- chamber 34 on the opposite sides of the set diameter of part 13 forms a ring-shaped distributor ring to allow and lubricant that shaped shoulder 15, which sits in the fixed stop 15 in the upper part of the chamber 34, before Vergegen a head cover surface 19 of the jacket pipe 16 to preserve contamination by drilling mud when can put to the upward migration of the latter of the mandrel 12 with respect to the jacket tube 16 in with respect to the cathedral 12; the purpose of a way wanders up and down that in itself is related to will be explained later. Interacting internal and oil-sealed compensating transitions dealt with the exterior Wedges 22 on the jacket pipe 16 or on 20 communicate is completely familiar. According to the invention ver-thorn 12 ensure the transmission of rotational forces, the annular chamber 36 runs downwards inside or moments from the mandrel 12 onto the jacket tube 16, halfway through the lower middle element 28 from the foot however, in between a longitudinal movement of the end of the upper middle member 26 to the head such that that the jacket tube 16 ends free to move the lowermost element 30. Close above the up or down with respect to the mandrel 12, 25 lowermost element 30 has the annular chamber while rotational forces differ from a drill pipe, 36 with the external environment of the balance engages in the socket end 17, via the jacket transition 10 via several bores 42 connecting pipe 16 up to a strand of collars (not manure for the purpose of putting pressure on the lower end shown) to maintain the at the lower end of the annular chamber 36, the Casing 16 for the purpose of rotating a drill bit 30 equal to the diameter of any, the balance is connected in a known manner. transition 10 surrounding fluid is. Close above

The jacket tube 16 is composed of several (in the Dar- half of the upper end of the lowest element 30 is in position four) elongated tube elements 24, 26, 28 the exterior of the part 33 of the dome 12 a block and 30, the uppermost one upper ring 43 fixed, but detachably attached, middle, a lower middle or a lower 35 holds against fluid with respect to the dome 12 form a tight element and fixed, but detachable with the help and is forced to wanpassender interior together with this and male threads are connected; the uppermost element 24 appears in FIGS. 1 a and snap rings 44 and 46, respectively; the blocking ring 43 Ib, the upper middle element 26 in Fig. Ib also has a double set of sealing packs and Ic, the lower middle element 28 in Fig. 48 attached to it and shown in sliding Fig. 1 c and the lowermost element 30 in FIGS. 1 c sealing the inner surface of the central bore 14 and 1 d. The uppermost element 24 extends downwards touching an annular piston element bil inside the upper middle element 26 so that the lower end of the uppermost element 24 can slide axially in the lower annular chamber. The blocking ring 43 is so shaped to lay shoulder 32 within the upper middle 45 that when the shoulder 15 makes contact with element 26; against this shoulder comes in the head cover surface 19, the bores 42 abutting contact a firm, but releasable contact is still located below it, so a central part of the dome 12 seated abutment bond between the lower part of the annular ring 35 (see Fig Ib), when the mandrel 12 is lifted upwardly pretensioned 50 through the space 36 and the outer environment of the off-action of the drill string 50 level transition 10 in all relative positions of the or while the casing tube 16 holds the mandrel 12 and the casing tube 16,
The dome 12 has a central bore 50 that is pulled down by chisels (not shown). goes through its entire length and has the purpose of still another part 33 with settled through flushing medium such as drilling mud from the drill pipe knife (see Fig. Ib and Ic) of the dome 12 extends 55 to guide the drill bit to work properly after this let down from part 18 to the lower end of the. The central bore 50 has with the upper mandrel 12 and forms in connection with the part of the lower annular chamber 36 via multiple central bore 14 of the jacket tube 16 within the rere bores 52 in the dome 12 just above the upper central element 26 an axially lower, blocking ring 43 at such an annular space 34 and within the un- 60 position connection that when the end 32 of the lower middle element 28 forms a similar, axially uppermost element 24 with the upper surface of the tapering annular space 36; the annular abutment ring 35 is in contact, the bores 52, shaped spaces 34 and 36 are separated from one another by below the lower end of the upper central one bore part 27 with a stepped diameter element 26. The bores 52 allow that of the upper central element 26 separately, the sliding 65 flushing medium from the central bore 50 to enter the upper part of the annular chamber 36 which is received on the exterior of the part 33, and with a suitable sealing packing 38 this becomes a hydraulic force between the blok- (see Fig. 1c) is provided to form a seal between the ring 43 and the lower end of the

Claims (1)

upper middle element 26 exerts so that the pressure has the tendency to the jacket tube 16 after to lift up with respect to the mandrel 12. The pressure in the bore 50 applied to the drill bit is applied, acts in the sense that a downward force on the jacket tube 16 with reference is exerted on the mandrel 12. This downward force is equal to the pressure difference between the pressure inside the bore 50 and any pressure outside the equalization junction 10 multiplied by the cross-sectional area of bore 114 of lower member 30. In a similar manner Thus, the force that tries to lift the jacket tube 16 is equal to the same pressure difference multiplied by the cross-sectional area of the chamber 36. Thus, when the cross-sectional area of the Chamber 36 is equal to the cross-sectional area of bore 114, the downward force acting on the Jacket pipe 16, which strives to stretch the compensation transition 10, equal to one opposite be on the jacket tube 16 upward force, which strives to the compensation transition to shorten, thus eliminating any tendency for pressure differential expansion. For certain purposes it may be desirable to have the cross-sectional area of the chamber 36 slightly larger or larger smaller than the cross-sectional area of the bore 114. On this relationship have such factors Influence such as the construction of the drill bit or fishing tool currently being used, the properties drilling mud and drilling progress. Such a departure from the equality of the Areas is considered as a possible, desirable modification within the invention, those in the framework of the basic idea of a balance of the applied at the balance transition Forces falls. In the event that the circuit is used in the opposite direction, so that the flushing medium in the annulus outside of the compensation transition 10 is pumped down and through the bores 14 and 50 returns upwards, the forces described above are reversed. As the above explained Forces but all reverse in the direction, the balance transition remains during such a transition Counter-cycle also in equilibrium. The operation of equalizing junction 10 is the same as that described in U.S. Patent No. 2996131 has been described, but with the exception of the compensation of the axial forces described here above. The advantages peculiar to the equalizing transition balanced according to the invention can be specified as follows: The inventive balance between the tendencies, the Making the compensation transition longer or shorter prevents the additive or subtractive deviation the pressure from the required downward pressure on the drill bit; rather, this is at the compensation transition of the present construction depends solely on the weight of the collars that are inserted between the lowermost end of the compensation transition 10 and the drill bit. These Downward force remains constant within very narrow limits as the bit progresses downward and brings the hole deeper. The use of the balanced transition 10 places ίο also in the latter itself the tensions among those Stresses that were caused in transitions according to the prior art when the Force of the pressure fluid is expressed in a force that strives to lengthen the transition and him to impart the effect of a hydraulic jack between the drill pipe and the collars. Such forces tend to twist the transition itself and, as a result, the To jam splines, so its useful value as a length adjustment member within the drill string to reduce and also the tendency of the drill string to wobble or tumble in the to increase the part lying directly above the equalization transition. It is known per se that compressive stresses which are applied lengthways to a drill string, increase its inclination when Turning to flutter or tumble. Claim: Hydraulic compensation transition for drill rods with an inner one on the drill rod connected, hollow mandrel and an outer casing tube carrying the drilling tool, which is telescopically movable lengthways to the mandrel, but is torsionally rigidly connected to it, characterized by an annular chamber (36) between the mandrel (12) and the jacket tube (16), bores (52) for admitting the flushing medium from the hollow mandrel (12) into the chamber (36), one below the bores (52) on the mandrel (12) clamped and sealing with the Chamber wall cooperating ring (43), which the chamber (36) in an upper section and a lower section divided, 4.5 which in each case at its end by the at this Place narrowed inner diameter of the jacket tube are limited, the cross-sectional area of the chamber (36) in the upper section has the same area as a circle, the diameter of which go equal to the bore (114) of the jacket pipe (16) is at the lowest end, and holes (42) in the casing tube (16), which the lower Connect section of the chamber to the borehole. Considered publications:
U.S. Patent Nos. 2,818,232, 2,996,131. 1 sheet of drawings