US3042377A - Oil well derrick crown block - Google Patents

Description

July 3, 1962 J. R. WOOLSLAYER ETAL 3,04

OIL WELL DERRICK CROWN BLOCK Filed Jan. 29, 1960 3 Sheets-Sheet 1 'Y" /2 \VI /2 m u 3 IN V EN TORS JOJZP/l 4?. IWOLSZAYER YC'EC/A J'IVK/IVS July 3, 1962 J. R. WOOLSLAYER EIAL 3,042,377

011. WELL DERRICK CROWN BLOCK Filed Jan. 29, I960 3 Sheets-Sheet 2 INVENTORS JOSEPH R. W-SZAYFR BY C'C/l JENKINS Z l v I; f p

July 3, 1962 J. R. WOOLSLAYER ETAL 3,042,377

011. WELL DERRICK CROWN BLOCK Filed Jan. 29, 1960 5 Sheets-Sheet 3 iii! IN VEN TORS JOS'P/l R. WSZAYER Y 666/! J'N/(l/VS 5, ArrQR/VEKS 3,042,377 H. WELL DECK ERUWN ELQCK Joseph R. Woolslayer and Cecil Jenkins, Tulsa, @klEL, assignors to Lee C. Moore Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Jan. 29, 196%, Ser. No. 5,448 3 Claims. (Cl. 254--19tl) This invention relates to crown blocks for oil well 'derricks, meaning conventional derricks and also portable masts. The invention pertains more particularly to a crown block that can be used in drilling three wells which are only a few feet apart, without moving the derrick.

In some locations it is desirable to drill two or more wells without moving the drilling derrick. In such cases the derrick is provided with a large enough base to accommodate the number of Wells that it is desired to drill. To position the crown block over each of the hole locations in turn, it is slid across the top of the derrick from one position to another. Since it is desirable that the drawworks remain in the same location for all positions of the crown block, the problem arises as to how to keep the fast line from making too sharp an angle with the drawworks drum when the crown block is in some of its positions. A way to solve the problem when only two wells are being drilled side by side is shown in Patent 2,744,725. In that patent a single fast line sheave is shifted to a different location relative to the rest of the sheaves of the crown block when the crown block is moved from one well location to the other. Due to such change in relative position of the fast line sheave, the flight angle between the fast line and the drawworks drum remains the same in both positions of the crown block. However, the arrangement shown in the patent is not suitable for drilling three wells spaced lengthwise of the drawworks drum.

It is among the objects of this invention to provide a crown block that can drill three wells without changing the position of the derrick, which always provides for a satisfactory flight angle between the fast line and the drawworks, in which the relative positions of the main sheaves in the crown block are not changed, and which is suitable for use with a mast that can be tilted backward and used as the boom of a crane.

In accordance with this invention a row of parallel sheaves is journaled in a crown block frame on a common axis. The frame is adapted to be mounted on top of a derrick, with the row of sheaves positioned over the location of one of the two or three uniformly spaced wells to be drilled. The frame is shiftable on the mast axially of the sheaves to position them over each of the well locations as desired. Two fast line sheaves are disposed substantially edge to edge on substantially parallel axes transverse to the common axis of the row of sheaves. Each of the fast line sheaves has a diameter approximately equal to the distance that they are moved radially when the frame is shifted on the mast from one well location to the next one. The frame may also support guide sheaves below and behind the fast sheaves for holding the line on a fast sheave when the crown block is mounted on a mast that is tilted for use as a boom. With this crown block, the fast line will leave the drawworks drum at substantially the same angle, regardless of which well is being drilled.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which FIG. 1 is a side view of a mast type of derrick supporting our crown block;

FIG. 2 is a fragmentary rear view of the mast and crown block;

FIG. 3; is a side view showing the mast leaning backward and serving as a crane boom;

ddllzfi'll Fatented July 3, 1 862 FIG. 4 is an enlarged rear view of the crown block;

FIG. 5 is a plan view thereof;

FIG. 6 is a side view; and

FIGS. 7, 8 and 9 are diagrams indicating the different positions of the crown block when drilling the three wells.

Referring to FIGS. 1, 2 and 3 of the drawings, a wide oil well drilling mast is formed from two upwardly con verging box type legs 1 hinged at their lower ends to a suitable substructure Z and connected at their upper ends by l-beams 3. Spanning the front of the legs is a racking platform 4. The mast is held upright by a gin pole 5, also mounted on the substructure and against which the mast leans. Of course, the mast and gin pole are detachably connected together. Mounted on top of the mast is a crown block that supports lines 6, from which a traveling block 7 is suspended in the mast. The lines include the usual fast line 8 extending from the crown block down to a drawworks drum 9 behind the mast. hie drum remains in the same position on the substructure, regardless of which of the three wells, that the mast is designed to drill, is being drilled. Extended center lines of the three equally spaced wells have been indicated in FIGS. 2, 7, 8 and 9 by parallel broken lines referred to by the letters A, B and C. This mast is designed so that it can be used as a crane, by attaching a cable to its upper end and then disconnecting the gin pole from the base so that the mast can tilt backward as the line is payed out from a suitable anchor point. When that occurs, as shown in FIG. 3, the traveling block swings backward out of the mast and can be used for picking up material behind the substructure.

In accordance with this invention, the crown block includes a frame 12 mounted on the I-beams at the top of the mast. The frame can be secured to the beams in any one of three equally spaced positions along their length. The distance between those positions corresponds to the distance between the well locations. As shown in FIGS. 4, 5 and 6, the frame includes three laterally spaced beams l3, l4- and 15 rigidly connected at the front ends by a cross channel 16. The rear ends of the two outer beams extend beyond the center beam and are rigidly connected by a pair of laterally spaced cross beams 17 mounted thereon. Mounted on center beam 14 and outer beam 15 about midway between their ends are pedestals 18 that support a shaft 19, on which a plurality of parallel sheaves 20 are journaled. These sheaves support lines 6 that support the traveling block '7 In back of the center of shaft 19, a pair of pedestals 22 are mounted on cross beams 17 for supporting a shaft 23, on which a fast line sheave 24 is journaled between those beams. It is preferred that the axis of this sheave be substantially perpendicular to shaft 19 at a point midway between the ends of that shaft. At the opposite end of the cross beams they support another pair of pedestals 25, in which there is a shaft 2d of which a second fast sheave 27 is journaled. The adjoining edges of the two sheaves are located as close together as possible, but only one fast line sheave is used at a time as will now be explained.

In FIGS. 2 and 8 of the drawings, the crown block is shown in the position it occupies while the center well B is being drilled. It will be seen that the cluster of sheaves it} is located above the well being drilled so that the hook 28 of the traveling block will hang directly over the well. The drawworks drum 9 is mounted in such a position that its central radial plane substantially coincides with a vertical plane containing the inner edge of the first fast line sheave 24, so that when the fast line 8 extends from the center of the drum up to the sheave the line likewise will lie in substantially the same vertical plane. Consequently, when the line is at either end of the drum, the angle between the plane just mentioned and the fast line is not so severe as to wear the line unduly. The line from the drum passes over the top of sheave 24- and then extends down to the traveling block. From that block the line extends up to the cluster of sheaves in front of the fast sheave and then down and up until the line leaves the sheave cluster and is dead ended at a suitable point. Fast line sheave 27 is idle.

When either of the other wells A or C is being drilled, the crown block is moved either to the right or to the left of the central position shown in PEG. 2,. Thus, to drill well C, the crown block is moved across the top of the mast to the left as viewed from behind in FIG. 2 until the traveling block is directly above the new well location. The crown block is then resecured to l-beams 3. If nothing more were done, it will be seen that the fast line then would make quite an angle with the center of the drawworks drum, and a still greater angle as the line was wound around the right-hand end of the drum. To prevent such a situation from occurring and to make the maximum and minimum angles between the fast line and the drum substantially the same as when the center well was being drilled, the line is restrung so that the line extends from the drum up the right hand side of fast line sheave 24 and then over it and down to the traveling block before being reeved over the crown block. This arrangement is indicated in FIG. 7. In addition, to obtain the desired result it also is necessary that the diameter of the fast line sheave be approximately equal to the distance that the crown block is moved; i.e. the distance between adjacent wells. Some slight difference can be tolerated, however, depending on the height of the mast, without making any significant difference in the flight angle between the fast line sheave and the drum. This invention enables the relation of the fast line to the drum to be made exactly the same if desired, regardless of whether well B or well C is being drilled.

When it is desired to drill well A, the crown block is moved in the opposite direction across the mast for a distance equal to twice the spacing between two adjacent wells, whereupon the traveling block will hang directly over the new well location. While well A is being drilled, the first fast line sheave 24 is idle and the second fast line sheave 27 supports the line. In other words, without restringing the line, it is lifted from sheave 24 and hung over sheave 27 so that the fast line extends from the drum up to the left-hand side of the second sheave as shown in FIG. 9. Since both sheaves are substantially the same size and close together, and since the wells are equally spaced apart, the angle between the fast line and the drum can be the same in this drilling position as in the other two.

Two widely spaced wells can be drilled, if desired, by omitting center well B and drilling only wells A and C. In that case the arrangement shown in FIG. 8 could be used as the tilting crane position.

Another feature of this invention, which is not applicable When a standard four legged derrick is used, is that in case it is desired to employ the mast as a crane boom as shown in FIG. 3, the angle of the fast line sheaves with the ground when the mast is tilted will not cause the portion of the line that extends from the active fast line sheave down to the traveling block to slip off that sheave. This is because two small guide sheaves 31 and 32 are mounted at the back of the crown block frame below and behind the fast line sheaves. One of the guide sheaves 31 is below the right-hand side of the first fast line sheave 24, where it is journaled on a shaft 33 projecting from one end of a tube 34 extending laterally along the frame through frame beam 15, in which the tube is rigidly mounted as shown in FIG. 4. The other guide sheave 32 is below the point where the sides or edges of the fast line sheaves nearly touch, and it is slidably mounted on a shaft 35 secured in tube 34 and another tube 36 projecting from beam 13. When the crown block is in the central position shown in FIG. 2 and the mast is tilted as in FIG. 3, the line extending down from the fast line sheave will engage the front of the right-hand guide sheave 3i and then extend down to the traveling block. Consequently, the line will not slip off the fast sheave. When the crown block is in position C and the mast is tilted, the line extending between the fast line sheave and the traveling block engages the front of the other guide sheave 32, which at that time is in its right-hand position on shaft 355. If the crown block is in its right-hand position shown in PEG. 9 and the mast is tilted, the line between the second fast line sheave 2'7 and the traveling block will engage the front of the guide sheave 32 in its left-hand position on its shaft.

By having shaft 19 extend crosswise of frame 12, lines 6 clear rear beam 3 at the top of the mast when tilted, as shown in FIG. 3. If the mast is not to be tilted, shaft 19 could just as well extend from front to back of the frame.

If a rare case should arise where the three wells are not to be uniformly spaced, the two fast sheaves should not have the same diameter. For wells having the spacing of wells B and C, sheave 24 would remain the size indicated in the drawings, but for a different spacing between wells A and B, the diameter of sheave 27 would be changed accordingly. its diameter, as before, should be approximately equal to the distance it would be moved radially when the frame is shifted in a direction toward sheave 2-4 to move the traveling block from above well B to a point above well A. However, if that distance is greater than shown in FIGS. 8 and 9, sheave 27 would be made larger than sheave 24. If the distance is less, sheave 27 would be made smaller.

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. Oil well drilling apparatus comprising a derrick having a front and back and two sides and having top beams forming its upper end, a crown block frame adjustably mounted on said top beams, means for detachably connecting the frame to the beams in any one of three different predetermined positions along a line extending from side to side of the derrick, said positions consisting of two side positions and an intermediate position, a row of parallel sheaves journaled in the frame on a common axis, a first fast line sheave iournaled in the frame directly behind said row of sheaves on an axis extending from front to back of the derrick, a second fast line sheave journaled in the frame beside the first fast line sheave and in substantially the same plane, the two fast line sheaves being disposed substantially edge to edge, the first fast line sheave having a diameter approximately equal to the distance between said intermediate position of the frame and its side position at the side of the derrick adjacent the second fast line sheave, and the second fast line sheave having a diameter approximately equal to the distance between said intermediate position of the frame and its other side position.

2. Oil well drilling apparatus comprising a tiltable mast having a front and back and two sides and having top beams forming its upper end, a crown block frame adjustably mounted on said top beams, means for detachably connecting the frame to the beams in any one of three different substantially uniformly spaced predetermined positions along a line extending from side to side of the derrick, said positions consisting of two side positions and an intermediate position, a row of parallel sheaves journaled in the frame on a common axis extending from side to side of the mast, a pair of fast line sheaves with substantially equal diameters mounted in the frame substantially edge to edge behind said row of sheaves on substantially parallel axes transverse to said common axis, the axis 'of one of said fast line sheaves being located substantially midway of said row of sheaves, said fast line sheave diameter being approximately equal to the distance between said intermediate position of the frame and either of its side positions, and a guide sheave journaled in the frame behind said fast line sheaves on an axis substantially parallel to said common axis, the front edge of the guide sheave being located below the fast line sheaves Where they are edge to edge.

References Cited in the file of this patent UNITED STATES PATENTS 1,673,346 Bennett June 12, 1928 1,797,406 Erlewine Mar. 24, 1931 2,744,725 Woolslayer et al May 8, 1956

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