US3256660A - Vibration dampening well derrick frame - Google Patents

Description

June 21, 1966 R. cs. M MAKIN VIBRATION DAMPENING WELL DERRICK FRAME 2 Sheets-Sheet 1 Filed Aug. 2, 1963 INVENTOR ROBERT G.M MAK/N TTO N ES June 2l, 1966 R. G. M MAKIN 3,256,660

VIBRATION DAMPENING WELL DERRICK FRAME Filed Aug. 2, 1963 2 Sheets-Sheet 2 INVENTOR ROBERT a. MCMA K/N United States Patent 3,256,660 VIBRATIGN DAMPENING W ELL DERRICK FRAME Robert G. McMakin, 410 W. Ruby Drive, Piacentia, (lalif. Filed Aug. 2, 1963, Ser. No. 299,6(99 2 Claims. (Cl. 52-299) This invention relates to an oil-well derrick and more particularly to a novel derrick substructure which provides a practical means for substantially reducing the transmission of vibrations from the derrick and drilling equipment through the ground to the area surrounding the derrick.

The derrick used in conjunction with drilling of oil wells and in other oil-field operations is generally mounted on a substructure which includes concrete piers. The derrick legs are rigidly attached to these piers, either directly, or through posts, skid beams, or some other intermediate structure. Some large and heavy items of drilling equipment such as the rotary table, and sometimes the draw-works, may be located Within the confines of the derrick frame, but supported separately rather than supported by the derrick. In that case the supports for such equipment are generally rigidly connected to the ground.

In conjunction with a drilling operation, the derrick and drilling equipment are subjected to many shocks and varying forces from such sources. as acceleration and deceleration of the drill string during hoisting and lowering, rotation of the drill string during drilling, operation of engines, pumps, etc. These forces cause horizontal, vertical and torsional oscillations which result in severe vibration of the derrick and the drilling equipment. This vibration is transmitted to the ground through the rigid substructure and supports. In areas which are densely populated or which include industrial installations using highly sensitive instruments in their operation, the ground vibrations are highly objectionable and sometimes make drilling prohibitive. Prior to this invention no satisfactory means of reducing these vibrations had been found. Thus drillers were restricted as to the areas in which drilling operations could be carried out. This restriction often forced inefiicient development of an oil field result ing in high costs and reduced production.

Covers or enclosures have sometimes been placed over derricks to reduce the noise caused by vibrations in the derrick and by the engines and other operating equipment. Such enclosures, however, are of no benefit in reducing ground vibrations.

Individual pieces of equipment such as the crown blocks have sometimes been resiliently mounted on the derrick frame. The purpose of this was to reduce the stresses in the derrick frame rather than to reduce ground vibrations. Because of the numerous sources of derrick vibrations, it was not practical as a means of reducing ground vibration.

It is the general object of this invention to provide a novel means for reducing transmission of derrick and drilling equipment vibrations to the ground.

A more specific object of this invention is to provide a novel substructure and support system for a derrick and drilling equipment so as to reduce transmissions of vibrations to the ground.

Another object of this invention is the reduction of 3,25t5fi6fi Patented June 21, 1966 ground vibrations by providing novel structural means for transmitting the load of the rotary table to the corner supports of the derrick and resiliently supporting both the rotary table and the derrick at these corners.

A further object of this invention is to reduce ground vibrations by providing a novel arrangement of structural members for dampening a substantial portion of the rotary table vibrations, whether due to variations of vertical loads or due to horizontally directed or torsional forces, and for transmitting the rotary table load to the corners of the derrick where the members are resiliently mounted.

These and other objects and advantages of this invention will be apparent from the following detailed description of a typical preferred embodiment of the invention. Throughout this description, reference is made to the accompanying drawings in which:

FIGUREl is an elevation view of the derrick substructure and portions of the derrick.

FIGURE 2 is a plan view of the derrick substructure and portions of the derrick.

FIGURE 3 is a sectional view along lines 33 of FIGURE 2.

FIGURE 4 is a sectional View along lines 4-4 of FIGURE 3.

As shown in FIGURES 1 and 2, the particular embodiment described herein incorporates a portable oil well derrick with skid beams 1. The legs of the derrick frame 2 are connected to the skid beams 1 through standard connectors 3 which are bolted to plates 4, which in turn are welded to the skid beams. A short beam section 5 is located at each corner to provide sufficient surface for attachment of the derrick legs. The derrick is braced by angle members 6 and includes a fioor 7 and a series of floor support beams 8. Located near the center of the floor is the rotary table 9. All of the above described structure per se is old and forms a part of this invention only insofar as it cooperates with the novel substructure described below.

Due to the symmetry of the structure shown in the drawings, many similar elements are repeated at more than one location. For purposes of clarity the same reference numeral has been used for each of such similar parts in many instances.

Located at each of the four corners of the derrick and supporting the derrick via the skid beams 1 are vibration isolators 10. These may be any type of resilient supports which are strong enough to support the loads placed thereon and sufficiently resilient to dampen severe vibrations in all directions without substantially increasing the amplitude of derrick movement. In practice two sets of steel spring vibration isolators such as the Korfund Vibro-Isolators type SlW at each corner have proven satisfactory. These vibration isolators 10 are attached to plates 11 which are supported on the ground. Beams 12 are welded to each plate 11 to prevent buckling.

The rotary table 9 is normally supported on the ground by vertical posts. Although the vibrations from the rote ry table could be removed to some extent by resiliently mounting these posts on the ground, in the preferred embodiment shown in the drawings the rotary table is supported on the same vibration isolators 10 as is the derrick frame. This substantially reduces the differential movement between the derrick frame, the fioor 7, and the rotary table 9, thus reducing the stresses in these members and in equipment which may be connected to more than one of these members. An additional ad vantage is gained by carrying the rotary table load to the corners. The structure used to carry this load is arranged so as to act as a dampening system itself, to eliminate, both the vertically and horizontally directed components of a substantial portion of the rotary table vibrations before they reach the vibration isolators. Such an arrangement is utilized in the preferred embodiment shown in the accompanying drawings.

The structure for carrying the rotary table load may be described by first referring to FIGURES 1 and 2 wherein beams 13 and 14 are shown as supported at each of their ends on plates 4 and on extensions 15 of these plates. It is important that beams 13 and 14 be supported only near their ends, leaving a space 26 between these beams and skid beams 1. This permits horizontal and vertical flexing of beams 13 and 14 and thereby results in a dampening elfect. As can be seen in FIGURE 2, beam 13 extends along one side of the derrick and beam 14 extends along the opposite side. Beams 13 and 14 are stabilized against tipping about their longitudinal axis by angle members 38. Each member 38 is welded at one end to a skid beam 1 which runs transverse to beams 13 and 14, and at its opposite end to either beam 13 or 14 near the upper flange of the latter.

Near the upper left-hand corner of FIGURE 2, is shown an anchor beam 39. The dead end of the hoisting cable is attached to this anchor beam. The anchor beam is preferably securely anchored to skid beams 1 in order to transmit shocks from the hoisting cable to the skid beams. It will be noted that this leaves the mid portion of beam 14 unrestricted to flex in a horizontal plane as well as a vertical plane. Alternatively the anchor beam can be connected to beam 14 at one end, thereby transmitting a portion of the shock to that beam.

Supported on beams 13 and 14 are beams 16 and 17. These beams run in a direction transverse to beams 13 and 14 and are supported on each side of the center of beams 13 and 14. The means illustrated for attaching beams 16 and 17 to each of beams 13 and 14 are similar, so only the attachment of beam 16 to beam 13 shown in the left side of FIGURE 3 will be described. In the particular embodiment shown in the drawings, beams 16 and 17 are of such a height that the vertical distance between the ground and the derrick floor makes it necessary for a special connection to be constructed at the ends of these beams. Beam 16 is shown as having a section cut from the lower portion at its end. The beam is stiffened by plates 18 and 19. A plate similar to plate 19 is also attached on the opposite side of the web of beam 16. Plates 18 and 19 are welded to beam 16 and plate 18 is bolted to beam 13. Another vertical plate 20 is welded to the web of beam 13. A horizontal plate is welded at the top of plate 20. The lower flange of beam 16 is bolted to plate 21. This connection would vary with the beam sizes used in carrying out this invention, the purpose being to provide a sturdy and rigid connection between beams 13 and 16.

As is best shown in FIGURES 2 and 3, the rotary table rests on beams 22 and 23 which are supported on beams 24 and 25. As shown in FIGURE 4, a plate 27 is welded near each end of each of the beams 22 and 23. Each of these plates is also welded to either beam 24 or 25 as appropriate. Beams 22 and 23 each also extend beyond plates 27 and are welded to beams 24 and 25. An additional plate 41 is welded between the flanges of beams 24 and 25, at right angles to the webs of these beams as shown in FIGURE 4.

Beams 24 and 25 parallel beams 16 and 17 respectively. Attached beneath each of these beams is a plate 40. The

beams and plates are supported by beams 16 and 17 on a series of shims 31. Beams 24 and 25 also support the floor 7. If desired, the floor may also be supported,

either partially or wholly, at its periphery by attachment to the derrick frame. Beams 32, 33, 34 and 35 extend between beams 24 and 25 and are welded thereto in order to rigidify the structure against rotation about the longitudinal axis of beams 24 and 25. Likewise, cross braces 36 and 37 are welded to beams 16 and 17 at various points along their length to provide transverse rigidity.

It is to be noted that beams 16 and 17, like beams 13 and 14 are supported only near their ends. Flexing of these beams is important in obtaining the desired dampening effect of the beam system. In order to obtain this dampening effect of the beams it has been found in practice that 36 WP 300 beams for beams 13 and 14, 33 WP beams for 16 and 17 and 20" I beams for 24 and 25 give the result desired. These sizes would, of course, necessarily be varied for different loadings.

The particular embodiment of the invention shown and described herein is used with a portable derrick which is mounted on skid beams. Although this embodiment is preferred because of the extensive use of portable derricks, the invention is also readily adaptable to permanent derrick structures. In the preferred embodiment disclosed herein, only one item of drilling equipment, i.e., the rotary table, located within the confines of the derrick has its own supporting system. to carry its load to the resilient supports located at the corners of the derrick. It should be understood that the term rotary table as used herein may include an engine for driving the rotary table in those instances where the rotary table is driven by its own engine rather than by the hoisting engine. It should also be understood that in those instances where the draw-works or other heavy equipment is located on the derrick floor, a support system similar to that used for the rotary table can be used. It is apparent that these and many other modifications can be made within the teachings of the above disclosure. It is therefore desired that the described exemplary embodiments of this invention be accepted as illustrative and not limiting, and that the scope of the invention be limited only by the definitions of the appended claims.

I claim:

1. Apparatus for use in drilling oil wells comprising an upright derrick frame, a rotary drilling table within said derrick frame, first and second elongated resilient members each supported solely at the ends thereof and together supporting said rotary table near their longitudinal centers to permit free flexural movement of the central portions of said members under vibratory load from said rotary table for dampening vibrations transmitted from said rotary table, means for supporting said first and second members comprising, third and fourth elongated resilient members each supported solely at the ends thereof and each connected to an end of said first and second members near the longitudinal center of said third and fourth members to permit free flexural horizontal and vertical movement of the central portions of said third and fourth members under vibratory load from said first and second members for dampening vibrations transmitted from said first and second members, and ground supported resilient means supporting the ends of said third and fourth members for dampening vibrations transmitted from said members.

2. A portable oil well derrick comprising a four-sided upright rectangular frame, horizontal skid beams at the lower end of said frame and supporting said frame at its four corners, a horizontal floor within said frame, a rotary table located in the central portion of said floor, elongated resilient horizontal means for supporting said rotary table and said floor and for dampening vibrations transmitted thereto from said rotary table and said floor, first and second horizontal members transverse to said horizontal means and supporting said horizontal means near the ends of said horizontal means and near the central portion of said first and second members, plates beneath the ends of said first and second members supporting said members on said skid beams and spacing said members from said skid beams, said horizontal means and said first and second horizontal members being supported solely at the ends thereof all but the end portions of said first and second members being free for horizontally and vertically directed flexing movement to dampen vibrations transmitted thereto from said horizontal means, and resilient means for supporting said skid beams beneath the corners of said frame for substantially reducing the transmission of vibrations from said frame and said first and second members to the ground.

References Cited by the Examiner UNITED STATES PATENTS Rhodes 52633 McEwen 52299 Tobin 52143 Johansen 175l95 X Steinbach 2482O X

Claims (1)

1. APPARATUS FOR USE IN DRILLING OIL WELLS COMPRISING AN UPRIGHT DERRICK FRAME, A ROTARY DRILLING TABLE WITHIN SAID DERRICK FRAME, FIRST AND SECOND ELONGATED RESILIENT MEMBERS EACH SUPPORTED SOLELY AT THE ENDS THEREOF AND TOGETHER SUPPORTING SAID ROTARY TABLE NEAR THEIR LONGITUDINAL CENTERS TO PERMIT FREE FLEXURAL MOVEMENT OF THE CENTRAL PORTIONS OF SAID MEMBERS UNDER VIBRATORY LOAD FROM SAID ROTARY TABLE FOR DAMPENING VIBRATIONS TRANSMITTED FROM SAID ROTARY TABLE, MEANS FOR SUPPORTING SAID FIRST AND SECOND MEMBERS COMPRISING, THIRD AND FOURTH ELONGATED RESILIENT MEMBERS EACH SUPPORTED SOLELY AT THE ENDS THEREOF AND EACH CONNECTED TO AN END OF SAID FIRST AND SECOND MEMBERS NEAR THE LONGITUDINAL CENTER OF SAID THIRD AND FOURTH MEMBERS TO PERMIT FREE FLEXURAL HORIZONTAL AND VERTICAL MOVEMENT OF THE CENTRAL PORTIONS OF SAID THIRD

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