US2744725A - Crown block for multiple well drilling - Google Patents

Description

y 8, 1956 H. J. WOOLSLAYER ET AL 2,744,725

CROWN BLOCK FOR MULTIPLE WELL DRILLING Filed Jan. 28, 1954 4 Sheets-Sheet l IN VEN TORS ATTOEA/EYS,

y 1956 H. J. WOOLSLAYER ETAL 2,744,725

CROWN BLOCK FOR MULTIPLE WELL DRILLING Filed Jan. 28, 1954 4 Sheets-Sheet 2 HOMER cseu ENKJNS Pal/L 5. 502 By sewn/4cm? BELL wi fm Lbezr 4 7- TUBA/E Y's,

May 8, 1956 H. J- WOOLSLAYER ETAL 2,744,725

CROWN BLOCK FOR MULTIPLE WELL DRILLING Filed Jan. 28, 1954 4 Sheets-Sheet 3 O O O O a Z Z a IN VEN TORS.

HO 5/? 001.5 M J MX SLAYEI? PQUL E. 80 6 BY ERWI/V/LCHMPBEAL 14", Ww 7Mw May 8, 1956 H. .1. WOOLSLAYER ETAL 2,744,725

CROWN BLOCK FOR MULTIPLE WELL DRILLING Filed Jan. 28, 1954 4 Sheets-Sheet 4 IN VEN TORS HOME/2 J. wooLsLA YER CECIL JENKINS 01. E. y iww A. camPaeLL United States Patent CROWN BLOCK FOR MULTIPLE WELL DRILLING Homer J. Woolslayer, Cecil Jenkins, and Paul E. Borg, Tulsa, Okla., andErwin A; Campbell, Wexford, Pa., assignors to Lee C. Moore Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Application January 28, 1954, Serial No. 406,872 11 Claims. (Cl. 254-190) This invention relates to oil well derrick crown blocks, and more particularly to a crown block for use in drilling two or more wells only a few feet apart without moving the derrick.

In some locations it becomes desirable to drill a multiplicity of Wells without moving the drilling derrick. The derrick has a large enough base to accommodate the number of wells that it is desired to drill and they are usually arranged in a rectangular pattern. To position the crown block over each of the hole locations in turn, it is slid horizontally on the top of the derrick from one position to another. However, since it is desirable that the drawworks remain in the same location for all positions of the crown block, it has been necessary when moving the crown block parallel to the axis of the drawworks drum to have a rather complex crown block arrangement in order to obtain proper alignment with the fast line which extends from the crown block to the drawworks. The crown block has had to be partly disassembled and reassembled for such moves, and the lines must be reeved anew. 'Of course, this all takes a-material amount of time, which delays the drilling operations.

It is among the objects of this invention to provide a crown block for multiple well drilling, which does not require the lines to be restrung when it is shifted from one drilling position to anotheron a derrick, which always provides for a satisfactory flight angle between the fast line and the drawworks, and which involves only a minimum of disassembly and reassembly when it is shifted. I

In accordance with this invention a row of sheaves is mounted on a horizontal shaft that is adapted to be shifted axially on a derrick from a drilling position over a well to a position for drilling a second well. Means are provided for journaling a fast line sheave selectively in two different locations lengthwise of the shaft. bothof its two locations the fast sheave has a point on its side edge which is disposed in substantially the same predetermined position relative to the row of sheaves. Consequently, if the shaftis shifted axially a distance equal to twice the distance between a pair of vertical planes that are parallel to the sheaves on the shaft and that contain the center of the fast sheave in its two locations, a point on the fast sheave diametrically opposite the first point can be maintained in substantially the same vertical plane parallel to the sheaves on the shaft as it was in before the shift. Because of this arrangement, the flight angle between the fast line and the drawworks never becomes excessive.

The invention is illustrated in the accompanying drawings, in which i I g Fig. 1 isa plan view of our crown block mounted on a derrick designed for drilling six holes;

Fig. '2 is'an end view of the crown block; 'Fig. 3 is a view of the drawworks side of the crown block taken on the line III-III of Fig. l;

2,744,725 Patented May 8, 1956 Figs. 4, 5 and 6 are views of a modification, corresponding to Figs. 1, 2 and 3, respectively; and

Fig. 7 is a diagram representing another arrangement.

Referring to Figs. 1, 2 and 3 of the drawings, a large oil well derrick has four upwardly converging legs 1 which are connected together at their top by a rectangular steel frame 2. Resting on the side members of the frame are the opposite ends of a pair of spaced parallel I-beams ice ' 3 and 4 forming the base of the crown block. Rigidly mounted on these beams is a pair of cross members 6. Mounted on the cross members midway between their ends are clamps 7, in which the opposite ends of a stationary crown shaft 8 are mounted. Journaled on this shaft are several sheaves S, the exact number being immaterial to this invention.

The crown block described this far is adjustable lengthwise of the derrick frame 2 and, with the derrick illustrated, beams 3 and 4 can be bolted to the frame in any one of three equally spaced positions. Cross members 6 are adjustable lengthwise of the beams and can be bolted thereto in either of two positions. With all of these adjustments, it will be seen that the center point of crown shaft 8 can be placed in six different locations, beneath each of which a well can be drilled. The locations of the wells areindicated bythe small circles a to f in Fig. 1.

At one side of the derrick the usual drawworks drum 10 is located, with its axis parallel to the crown shaft. To guide the fast line 11 from the drum to one of the sheaves on the crown block shaft, a fast sheave 12 is provided. This sheave is mounted in such a position that the line from the. drum passes over it for about and then down and preferably a short distance around one of the end sheaves on the shaft. The fast sheave is journaled in bearings 13 mounted on the ends of a pair of spaced parallel horizontal channels 14 supported above sheaves S by braced inclined legs 16 and 17 mounted on cross members 6. As shown in Fig. 3, the bearings are in a location such that a point on the side edge of the sheave adjacent the opposite end of the channels is in a position to direct the fast line downward in the planes of that sheave and the underlying end sheave to the latter sheave. The point just mentioned, from which the fast line leaves the fast sheave for the end sheave in a cluster, is called herein the outer point of departure to distinguish it from the other point of departure where the fast line leaves the fast sheave for the drawworks. In the specific embodiment illustrated, the fast sheave lies in a plane tangent to sheaves S.

The drawworks drum is located with its central radial plane substantially coinciding with a vertical'plane (indicated by the line-p in Fig. 1) containing the inner point of departure on the side edge of the fast sheave from which the fast line leaves for the drawwork's. Consequently, the angle between that plane and the fast line when at either end of the drum is not so severe as to wear the line unduly. To also reduce the flight angle between the fast sheave and the line extending down to the drawworks, the sheave is tilted backward-away from the drawworks side of the derricks, as shown in Fig. 2. The line from the fast sheave to the end sheave passes only a few degrees around the latter and then extends down to the traveling block 18 and back up and over the next sheave on the crown shaft and then down and up until it leaves the opposite end of the crown block and extends down to the bottom of the derrick, where it is dead ended at the drawworks side.

It is a feature of this invention that channels 14 are long enough to permit the bearings to be moved along them and fastened to the opposite end of the channels in an overhanging position, with the outer point of departure on the side edge of the fast sheave positioned above the same end sheave as before. This shift of position of the fast sheave is made only when all of the sheaves are moved lengthwise of beams 3 and 4 to the broken line position in Figs. 1 and 3, in order to locate the crown shaft above the point where another well e is to be drilled. The fast sheave and bearings are not slid along channels 14 from one end to the other, but are picked up by hoisting apparatus (not shown) mounted on top of the derrick. When the fast sheave is lifted free of the channels it is swung around a half turn and redeposited between them, whereupon the bearings are bolted to the opposite end of the channels. The effect of turning the sheave 180 in this manner, as it is being moved from one end of the channels to the other, is to leave the same point on its edge above the end sheave as before, thereby avoiding having to first remove the line from the fast sheave and then run it in the opposite direction around the sheave.

It is important to note that the crown shaft is moved axially from one drilling position to the other a distance substantially equal to twice the distance between a pair of imaginary vertical planes that are parallel to sheaves S and that contain the points where the center of the fast sheave is located at opposite ends of channels 14. In other words, when the distance between the proposed pair of wells b and e is known, the crown block should be so constructed that the fast sheave can be moved lengthwise of the crown shaft a distance that is substantially half of the distance between the well centers. As a result, the inner point of departure on the side edge of the fast sheave, where the fast line leaves it for the drawworks, remains in substantially the same location relative to the derrick, regardless of whether the crown shaft is above well b or well 6. That is, the fast sheave point just mentioned remains in plane p, so that it bears the same relation to the center of the drawworks drum whether well b or well e is being drilled. This highly desirable result is brought about without restringing the drilling line and with only a minor adjustment in connection with the fast sheave.

When the fast sheave is in a plane tangent to sheave S, as it is in the embodiment described thus far, it is adjustable in a line parallel to the crown shaft. The two different locations for bearings 13 on channels 14 therefore are spaced substantially the same distance from opposite sides of the plane of the end sheave with which the fast sheave cooperates. It also is true in such a case that the two different locations of the axis of the fast sheave are spaced apart a distance substantially equal to the diameter of that sheave. Consequently, when the crown shaft is shifted axially a distance substantially equal to twice the diameter of the fast sheave, the benefits of this invention are obtained.

However, the fast sheave does not need to be tangent to the other sheaves, nor do the two different locations of its axis have to be spaced equidistant from the plane of the same end sheave. The advantages of this invention are still available as long as the outer point of departure on the side edge of the fast sheave keeps the same relation to the same end sheave, and the distance between the two parallel planes referred to in the second preceding paragraph is half the distance that the crown shaft is to be moved. This can be understood better by reference to Fig. 7, which represents diagrammatically a fragmentary plan view of a modification. The crown shaft 8, an end sheave S and a fast sheave are shown in two dilferent locations, one in full lines and one in broken lines. It will be seen that in both positions the other point of departure at one edge of the fast sheave is in the same location relative to the end sheave, and the opposite point on the fast sheave lies in the same plane p parallel to the end sheave. This is because the distance between the center points of shaft 8 in its two different positions is twice the distance between a pair of vertical planes s and t that are parallel to the end sheave S and contain the center of the fast sheave in the two different locations (one shown in dotted lines) it can occupy relative to the crown shaft.

In the modification shown in Figs. 4, 5 and 6 the row of crown block sheaves S, their supporting shaft 25, the cross members 26 and the supporting beams 27 and 28 are all arranged as in the first embodiment, but the fast sheave 29 is mounted below the beams on a bridge 31 that is connected to beams 27. The bridge is formed from two parallel channels, on which are mounted the adjustable bearings 32 that support the fast sheave in two different positions along the bridge. In one position the fast line 33 is directed from an outer point on the side edge of the fast sheave upward around one of the end sheaves. The diametrically opposite point on the fast sheave is directly below a guide sheave 34 that is journaled in arms 36 projecting outward and downward from beam 27. The fast line from the drawworks 37 passes over this guide sheave and then down around the fast sheave and up to the end sheave on the crown shaft. From there it goes down to the traveling block 38 and then back up around the next crown block sheave and then successively around the upper and lower sheaves until the line is dead-ended at the side of the derrick opposite to the drawworks side. The central radial plane of the drawworks drum lies in the plane of guide sheave 34.

When the crown shaft and sheaves are shifted axially to the broken line position in Figs. 4 and 6 to drill another well, the fast sheave and bearings are picked up and turned and remounted on the bridge in a location spaced substantially the diameter of the fast sheave from the first location. The inner point of departure on the side edge of the fast sheave therefore remains below the guide sheave. A diametrically opposite point on the fast sheave is below and a little in front of the same end sheave S as before the shift, because the crown shaft was moved twice the diameter of the fast sheave. Consequently, excessive flight angles are avoided without restringing the lines or making any material change in the crown block.

An advantage of this last embodiment of the invention is that guide sheave 34 prevents any change in the flight angle between the fast line and the fast sheave when the crown block is moved toward or away from the drawworks side of the derrick for drilling the other four wells. According to the provisions of the patent statutes, we have explained the principle of our invention and have illustrated and described what We now consider to represent its best embodiment. However, we desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

We claim:

1. An oil well derrick crown block for use in drilling a pair of closely spaced wells, comprising a horizontal shaft shiftable axially on a derrick from a drilling position over a well to a position for drilling a second well, a row of sheaves on the shaft, a fast line sheave, and supporting means for journaling the fast sheave selectively in two different locations lengthwise of said shaft with the outer point of departure at the same edge of the fast sheave in both of said locations remaining in substantially the same predetermined position relative to said row of sheaves, whereby if said shaft is shifted axially a distance equal to twice the distance between a pair of vertical planes that are parallel to the sheaves in said row and that contain the center of the fast sheave in said two locations, a point on the fast sheave diametrically opposite said first-mentioned point can be maintained in the same vertical plane parallel to the sheaves in said row as it was in before the shift.

2. A crown block in accordance with claim 1, including a guide sheave journaled on an axis parallel to said shaft inja position 'to direct the fast line from a point on the guide sheave to said diametrically opposite point 'on the fast sheave, the axes of the guide sheave and said shaftlying in horizontal planes on the same side of the fast sheave.

3. A crown block in accordance with claim 1, in which said fast sheave is at a lower level 'th'an said row of sheaves, and a guide sheave is journaled on an axis parallel to said shaft in a position to direct the fast line from a point on the guide sheave downward to said diametrically opposite point on the fast sheave.

4. An oil well derrick crown block for use in drilling a pair of closely spaced wells, comprising a horizontal shaft shiftable axially on a derrick ,from a drilling position over a well to a position for drilling a second well, a row of sheaves on the shaft, a fast line sheave, and supporting means for journaling the center of the fast sheave selectively in two different locations spaced substantially the same distance from opposite sides of the plane of an end sheave in said row, the fast sheave in both of said locations being positioned to direct a fast line from a point on its same side edge to and part way around said end sheave, whereby if said shaft is shifted axially a distance equal to twice the distance between said two locations, a point on the fast sheave diametrically opposite said first-mentioned point can be maintained in the same location it was in before the shift.

5. An oil well derrick crown block for use in drilling a pair of closely spaced wells, comprising supporting means adapted to be mounted on top of a derrick, a horizontal shaft mounted on said means and shiftable axially thereon from a drilling position over a well to a position for drilling a second well, a row of sheaves on the shaft, a fast line sheave, supporting means for journaling the fast sheave selectively in two different locations lengthwise of said shaft with the outer point of departure at the same edge of the fast sheave in both of said locations remaining in substantially the same predetermined position relative to said row of sheaves, whereby if said shaft is shifted axially on said supporting means a distance equal to twice the distance between a pair of vertical planes that are parallel to the sheaves in said row and that contain the center of the fast sheave in said two locations, a point on the fast sheave diametrically opposite said first-mentioned point can be maintained in the same vertical plane parallel to the sheaves in said row as it was in before the shift, and a guide sheave rotatably supported by said supporting means with its axis parallel to said shaft, the guide sheave being located substantially in said last-mentioned plane for directing the fast line to said diametrically opposite point on the fast sheave.

6. An oil well derrick crown block for use in multiple well drilling, comprising a horizontal shaft shiftable axially on a derrick from a drilling position over a well to a position for drilling a second well, a row of sheaves on the shaft, a fast line sheave in a plane tangent to said row of sheaves, and supporting means for journaling the fast sheave selectively in two ditferent'horizontally spaced locations in said plane, the distance between the two different locations of the axis of the fast sheave being substantially equal to the diameter of that sheave, and the fast sheave in both of said locations having its outer point of departure on its same side edge remaining in substantially the same predetermined position relative to said row of sheaves, whereby a diametrically opposite point on the fast sheave can be maintained in substantially the same location relative to the derrick when said shaft is moved axially a distance equal to substantially twice the diameter of the fast sheave.

7. An oil well derrick crown block for use in drilling a pair of closely spaced wells, comprising a pair of horizontally spaced parallel beams adapted to be mounted on top of a derrick with the locations of said well spaced lengthwise of the beams below the space between them,

a pair of horizontally spaced parallel cross members having their ends resting on said beams, means for fastening said cross members to the beams selectively in two different positions with the space between the cross members above either of said well locations, a horizontal shaft supported by said cross members transversely thereof, a row of sheaves on the shaft, a fast line sheave, and supporting means-for journaling the fast sheave selectively in two different locations spaced lengthwise of said beams a distance equal to substantially half the distance between said two different positions of said cross members, and the fast sheave in both of said locations having its outer point of departure on its same side edge remaining substantially the same predetermined position relative to said row of sheaves, whereby a diametrically opposite point on the fast sheave can be maintained in substantially the same location lengthwise of said beams regardless of which position said cross members are m.

8. A crown block in accordance with claim 7, in which said fast sheave supporting means is suspended from one of said beams, and a guide sheave is rotatably supported by said one beam or an axis parallel to said shaft.

9. An oil well derrick crown block for use in drilling a pair of closely spaced wells, comprising a horizontal shaft shiftable axially a predetermined distance on a derrick from a drilling position over a well to a position for drilling a second well, a row of sheaves on the shaft, a fast line sheave, and supporting means for journaling the fast sheave selectively in two different locations lengthwise of said shaft, the center of the fast sheave in said locations being disposed in vertical planes that are parallel to an end sheave in said row and are spaced apart a distance equal to substantially half said predetermined distance, the fast sheave in both of said locations being positioned to direct a fast line from a point on its same side edge to and part way around said end sheave, whereby when said shaft is shifted said predetermined distance a diametrically opposite point on the fast sheave can be maintained in substantially the same vertical plane parallel to said end sheave as it was in before the shift.

10. An oil well derrick crown block for use in drilling a pair of closely spaced wells, comprising a horizontal shaft shiftable axially a predetermined distance on a derrick from a drilling position over a well to a position for drilling a second well, a row of sheaves on the shaft, a fast line sheave, means supporting the fast sheave rotatably in a first location with a point on its edge in a position to direct a fast line therefrom to and part way around an end sheave in said row, and means for supporting the fast sheave rotatably in a second location spaced lengthwise of the shaft from said first location but with said point in substantially said lastmentioned position, said supporting means being disposed to locate the center of the fast sheave in two vertical planes parallel to said end sheave spaced apart a distance equal to substantially half the distance said end sheave is moved when said shaft is shifted said predetermined distance, whereby a point on the fast sheave diametrically opposite to said first-mentioned point can be maintained in substantially the same vertical plane parallel to said end sheave as it was in before the shift.

11. An oil well derrick crown block for use in drilling a pair of closely spaced wells, comprising a horizontal shaft shiftable axially a predetermined distance on a derrick from a drilling position over a well to a position for drilling a second well, a row of sheaves on the shaft, a fast line sheave in a plane tangent to an end sheave in said row and having a diameter equal to substantially half the distance said shaft is to be shifted, and supporting means for journaling the fast sheave selectively in two different horizontally spaced locations in said plane, the distance between the two different locations of the axis of the fast sheave being substantially equal to the diameter of that sheave, and the fast sheave being positioned to direct a fast line from a point on the fast sheave to and part Way around said end sheave, whereby a diametrically opposite point on the fast sheave can be maintained substantially midway between the two locations of said end sheave produced by shifting said shaft from one of its said positions to the other.

References Cited in the file of this patent 7 UNITED STATES PATENTS Goes'er Sept. 14, Henry Sept. 7, Clifford Apr. 17, Woolslayer et a1. Nov. 20, Roberson July 21,

OTHER REFERENCES Oil & Gas Journal, pp. 82-83, of January 18, 1954.

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