US2906493A - Washover pipe fluid by-pass sub - Google Patents

Description

Sept. 29, 1959 J. w. wHlTENER WASHOVER PIPE FLUID BY-PASS SUB Filed Dec. 16, 1957 United States Patent O f WASHOVER PIPE FLUID BY-PASS SUB James W. Whitener, Kingsville, Tex., assignor, by mesne assignments, to Jersey Production Research Company, Tulsa, Okla., a corporation of. Delaware Application December 16, 1957, Serial No. 702,922

4 Claims. (Cl. 251-346) ving mud by the drill pipe. When a washover pipe is lowered as the bottom section of the drill pipe, this situation is aggravated because of the very small clearance between the sides of the borehole and the exterior of the washover pipe. The drilling mud so ejected may overflow frompthe topmost drill pipe to the rig oo'r; manifestly, this is a very undesirable condition. To prevent rnud spillage, it has been the custom to plug the topmost section of drill pipe with a so-called surface plug. Not only is this a rather cumbersome practice but also it has been found to be not always effective.

Briefly described, the present invention contemplates the use of a pair of coupling members for coupling together lengths of drill pipe, preferably lat a joint near the bottom of the drill pipe being lowered into a borehole. The coupling members may be provided with male and female sections having tapered screw-threaded portions, with at least one radial port in the male section to permit uid communication between the inside and outside of the coupling member. The tapers ofthe screw-threaded portions are such that the two coupling sections can be readily brought together in a position to screw-threadedly engage each other. The two coupling members are loosely connected together by a mandrel connected to one of the members and engaging an internal shoulder on the other of the members so that the lowermost section of drill string can hang therefrom. Sealing means, such as an -ring seal, may be provided on the male section to engage the female section so as to seal oif the fluid by-pass ports when the two sections are screw-threaded together.

A more complete understanding of the invention may be obtained from the following description thereof when considered in connection with the accompanying drawing, wherein:

Fig. 1 is an elevational view, partially cut away, showing the invention in a typical operating locale, here shown as a iishing operation within a borehole;

Fig. 2 is a more detailed cross-sectional side view showing the details of the invention in a more perspicuous form wherein the components are shown in the relative positions that they will assume for equalizing pressure within and without the drill string; and

Fig. 3 is a showing similar to Fig. l with the components in an engaged position for drilling or fishing operations.

With reference now to Fig. l, there is shown a borehole 1 within which it has been assumed that a iish 41 has been lodged. A washover pipe 39 is shown as sur- Patented Sept.-29,-19'59 ICC rounding the uppermost portion of the lish immediately prior to inauguration of washover operations. A section of drill string 3 is coupled to the washover pipe 39 by means of coupling members 4, 5, 31, and 37.

With reference now to Fig. 3, the details ofthe coupling members 4, 5, 31, and 37 and certain component parts not shown in Fig. l are depicted. Coupling member 5 is screw-threadedly aiiixed at its upper end to the bottom of coupling member 4 which is attached to drill pipe 3. At its lower end, coupling member 5 is of reduced diameter and includes a section 9 of relatively uniform diameter terminated in a screw-threaded section 15. Screw-threaded section 15 engages matching internal screw threads 29 within coupling section or collar 31. The threads are tapered so as to facilitate the engagement of threads 15 in threads 29. Assuming that the lower section of drill pipe or washover pipe 39 is abutting against the bottom of the borehole or against a bridge of earth or rock around a fish so that rotation thereof will be resisted, after coupling sections 5 and 31 have been brought together clockwise rotation of the upper section of drill string will cause the two threaded sections to threadedly engage.

The section 9 is of relatively uniform diameter and contains a plurality of ports 13 which provide uid communication between the interior and exterior of coupling section 5. A sealing member, shown here as an O-ring 11, is provided between the ports 13 and the shoulder 10. The diameter of section 26 of collar 31 is only slightly greater than the diameter of section 9 of couplingmember 5 so that the lowermost male section of coupling member 5 and the upper portion of collar 31 will matingly engage. As section 26 slides over section 9, it will engage O-ring 11 to effectively seal ports 13 to prevent uid communication between the interior and exterior of the pipe through the ports.

The lower portion of collar 31 is provided with an internal shoulder 35. A matching external shoulder 33 is provided on mandrel 19, which mandrel 19 is vscrewthreaded at its upper end into the interior of coupling section 5 at the lower end thereof. While the drill string is being lowered into the borehole as lshown in Fig. 1, the lowermost section of drill string or washover pipe 39 will hang on mandrel 19 as more 'specifically shown in Fig. 2. One or more pressure equalizing ports 27m-ay -also be provided within mandrel 19 to serve the same function as ports 13. Collar 31 is coupled to drill pipel or washover pipe 39 by means of an auxiliary coupling member 37.

As the drill string is lowered into the well, the component parts of the coupling system above described will be as shown in Fig. 2. Fluid entering the bottom of washover pipe 39 and displaced upwardly will flow outwardly through ports 13 and 27 to provide a pressure relief for uid within the pipe. When the lowermost member (or washover pipe) 39 of the drill string has engaged the bottom of the borehole and the teeth 43 thereof havedug into the earth, the upper section of drill string 3 and coupling member 5 are lowered and rotated clockwise until the component parts thereof assume the positions shown in Fig. 3. The ports 13`and 27 will be sealed so that drilling uid may be circulated down through the drill string in the customary manner. i

As will be evident from the above description, this invention has the advantage of extreme simplicity and rugged reliability. It has been found that suicient drilling mud will invariably flow through the pressure equalizing ports 13 and 27 to prevent spillage of drilling mud to the rig floor from the topmost section of drill pipe. The connection provided by the invention is positive and sufficiently strong to enable normal drilling operations. The seal provided when the coupling members are screwthreaded together as shown in Fig. 3 will be found to be quite effective.

The invention is not to be restricted to the specific structural details, arrangements of parts, or circuit connecti'ons herein set forth, as various modifications thereof may be effected without departing from the spirit and scope of this invention.

What is claimed is:

1. A by-pass joint for coupling a string of drill pipe toa washover pipe including: a first pipe section adapted to be coupled to the string of drill pipe, said first pipe section having a lower portion of reduced outer diameter, said lower portion having a tapered threaded lowermost section and a plurality of radial openings between the inner and outer walls thereof; a second pipe section adapted to be coupled, to the washover pipe having tapered internal threads adapted to threadedly engage the tapered threaded section of said first pipe section, and a section above said tapered internal threads adapted to matingly engage said section of reduced diameter to seal said radial openings; and a pipe section threadedly engaging said first pipe section internally thereof and having an external shoulder near its lower end adapted to engage an internal shoulder within said second pipe section to limit separation of said first and second pipe sections; said external shoulder being positioned below said internal shoulder and projecting outwardly beyondv the inner wall of said internal shoulder.

2. A coupling for two sections of drill pipe comprising: a first coupling pipe adapted to screw-threadedly engage the upper of the two sections of drill pipe; a second coupling pipe adapted to screw-threadedly engage the lower of the two sections of drill pipe; said first coupling pipe having a section of reduced diameter terminated at its lower end in a tapered threaded portion adapted to engage tapered internal threads within said second coupling pipe; a plurality of radial openings in said section of reduced diameter above said tapered threaded portion for providing fluid communication between the interior and exterior of said first coupling pipe; annular sealing means above said radial openings on said reduced section; and means coupled to said first coupling pipe for supporting said second coupling pipe when said iirst and second coupling pipes are not screw-threadedly engaged, said second coupling pipe having a portion above said tapered intern-al threads, having a slightly greater diameter than the diameter of said section of reduced diameter so as to slide over` said section of reduced diameter to engage said sealing means when said first and second coupling pipes are screw-threaded together,

3. Apparatus for coupling together two sections of drilling string comprising: rst and second coupling pipe members adapted to be connected to the two sections of drilling string, said first coupling pipe member having an end section of reduced outer diameter adapted to matingly engage an end section of increased inner diameter of said second coupling pipe member, said end sections having tapered threaded portions adapted to threadedly engage each other, the taper thereof being sufiicient to facilitate the location of the male threaded portion in the female threaded portion; at least one radial port in the male end section to permit tiuid communication between the interior `and exterior thereof when said end sections are not screw-threaded together; means for sealing said at least one port when said end sections are screwthreaded together; and means connected to one of said two coupling pipe members to support the other of said two coupling pipe members when said tapered threaded portions are disengaged.

4. Apparatus for coupling together first and second lengths of drill pipe to permit egress of drilling uid laterally from the interior of the drill pipe while the drill pipe is being lowered into a borehole, comprising: first and second coupling pipe members respectively adapted to screw-threadedly engage the first and second lengths of drill pipe, said first and second coupling pipe members respectively having mating male and female sections with tapered screw-threaded portions adapted to screwthreadedly engage; an annular internal shoulder within said second4 coupling pipe member; an annular mandrel screw-threadedly engaging the interior of the male section of said first coupling pipe member and having an annular external shoulder adapted to engage said internal shoulder of said second coupling pipe member; at least References'Cited in the file of this patent UNITED STATES PATENTS 2,531,942v Lee Nov. 28, 1950

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