JPS63598B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to well drilling equipment, and more particularly to a stabilizer for a drill collar.

Drill collar stabilizers are used in directional drilling operations to adjust the angle of the borehole being drilled from the surface. By using drill collar stabilizers, it is possible to drill boreholes that extend at an angle to the vertical. The stabilizer can also be used to guide the drill string and drill bit when drilling vertically extending holes.

In order to extend the drill hole at an angle to the vertical, stabilizers are usually mounted between a series of drill collars. The drill color is
A heavy elongated tubular gathering member that can be bent in its longitudinal direction during excavation operations. The degree of flexion of the drill collar assembly is determined by the placement of the stabilizers with respect to the series of collars. The stabilizer leans against the wall of the perforation,
It acts as a fulcrum and allows the assembly of drill collars to flex around the fulcrum. that time,
The distance of the stabilizer on the drill collar is
Combined with the weight or force of the drill collar, it determines the degree of flexion of the drill collar assembly. The degree of flexure of the drill collar immediately adjacent to the drilling bit, as well as the degree of flexure of other drill collars located along the drilling hole, is determined as well.

It has become common for oil and gas to drill larger and deeper holes and at an angle to the vertical. Correspondingly, the methods and equipment required for drilling have become complex and varied, particularly for offshore drilling operations and equipment. For example, multiple holes can be drilled from an offshore drilling rig that is fixed at one particular location, with each hole extending in various directions. This is accomplished by drilling multiple holes oriented vertically or in various other directions. To allow multiple holes to be drilled from a single drilling rig location, each hole is placed relatively close together at the surface. As drilling progresses, the drilling angle of each hole is adjusted such that the drilling locations and depths span a relatively large area in a grid-like pattern. The drilling may also be directed into multiple formations at various depths and locations. In order to reach a plurality of different locations, it is necessary to adjust the drilling angle to have a very precise drilling angle. This is to ensure that the bottom of the borehole is within a few feet of the predetermined location. The location of the stabilizer along the assembly of drill collars and the weight of the drill collar adjusts the flexing of the assembly and thus the drilling angle. Therefore, in order to adjust the drilling angle, it is necessary to position the stabilizer at a plurality of different positions along the length of the drill collar. A computer is used to properly position the stabilizer on the drill collar assembly.

In order to adjust the drilling angle and direction of the borehole, a magnetic reading of the end of the borehole, i.e. a reading of the movement of the indication of the drilling angle by the earth's magnetic field, is carried out during the drilling, which depends on the depth at which the reading is taken. In combination with this, it can result in the determination of the spatial location of the perforation.

It is not uncommon to excavate to depths of 14,000 feet or more. The weight of the drill string is supported by the rig at the surface, while the drill bit is vertically loaded by the predetermined weight of the drill collars. Therefore,
Considerable forces are carried by the drill collar both during drilling operations and during raising and lowering the drilling string. For example, an axial force in the range of 200,000 ft is applied to the stabilizer during raising and lowering of the drill collar assembly, and a torque in the range of 60,000 ft is carried by the stabilizer during drilling operations. . During directional drilling, one stabilizer acts as a fulcrum between the wall of the borehole and the drill collar assembly. As a result, a huge torque is applied to the stabilizer. Drill collar stabilizers must therefore be made to withstand such forces and torques. In addition, the wear surfaces of the stabilizer must be made of hard materials such as steel, tungsten carbide, and the like.

U.S. Pat. No. 3,916,998 discloses a rigid stabilizer that can be slid over a segment of a drill collar and positioned axially at a desired location. The stabilizer has a main sleeve that is cylindrically shaped and has an axial passage for sliding over and axially positioning over the drill collar. Adjacent to the end of the main sleeve is a ring with a split. A covering sleeve slides over the collar segment and is screwed onto the end of the main sleeve. Tightening of the covering sleeve to the main sleeve, combined with the action of the split ring, allows the stabilizer to be connected to the collar. Significant torque must be applied to engage the stabilizer with the drill collar. When a stabilizer is used in combination with a magnetic device, the stabilizer must be of non-magnetic material. Because of this high torque requirement, the stabilizer according to US Pat. No. 3,916,998 is subject to severe erosion during operation, even though it is made of non-magnetic material.

In US Pat. Nos. 4,001,918 and 3,945,446, the drill collar is contractively mounted on the mating outer conical surfaces. A stabilizer having a conical inner surface is disclosed. The stabilizers of these patents only fit onto the drill collar at the location of the outer conical surface, since the retractive mounting of the stabilizer on the drill collar requires threaded engagement with the segment of the drill collar. must be placed.

US Patent Nos. 3410613, 3933203, 3894779,
Nos. 3,894,780, 3,528,490, and 2,813,697 disclose devices used to protect, support, or guide drilling or production strings. Each of these is made of a polymeric material and therefore generally cannot be suitably used as drill collar stabilizers. No.
No. 3410613, No. 3894780, No. 3164216 and No.
The device according to No. 2,813,697 is made of two semi-cylindrical pieces, whereas those according to Nos. 3,933,203, 3,894,779 and 3,528,499 are split and closed by a pin or bolt member. In some of these patents, the pipe or rod is adapted to rotate with respect to the device.

Another multi-piece device is disclosed in US Pat. No. 3,292,708. The tubular centralizer described in this patent is for production strings and has two clamping sections that are hinged together at one end and bolted together at the other end. held by the tightening portion;
A radially extending wing is adapted to engage the casing of the production well.

The two or more split piece devices are adapted to break and fall into the borehole. The segmented device made of polymeric material is also adapted to be able to be separated from the drill collar due to the elastic nature of the device.

The object of the invention is to provide a stabilizer device that can be placed in any desired position on the drill collar.

It is an object of the invention to
The object is to provide such a stabilizer that can be clamped onto the outer surface of the drill collar.

The object of the present invention is to create such a stabilizer that can provide adequate stabilization without increasing the sag bond in the drilling string. The object of the invention is to create a stabilizer that can be quickly placed and repositioned on a drill collar.

Another object of the invention is to provide a stabilizer made of non-magnetic material such that the stabilizer is free from interference with the magnetic information at the bottom of the borehole.

These and other objects of the invention are accomplished by a single split stabilizer.
The stabilizer includes a hollow, generally cylindrical body having a gap extending along its length. The stabilizer rotatably drives the drilling bit into an aperture extending therethrough.
It is adapted to accommodate an elongated tubular member. On the outer part of this hollow body, means are arranged for leaning on the inner surface of the borehole, so as to stabilize the elongated cylindrical assembly. It also includes means for clamping the stabilizer to the tubular assembly to prevent components of the means from separating from the stabilizer during use. In one feature of the invention, the stabilizer is made of non-magnetic material.

According to the invention, a stabilizer is used for an elongated cylindrical assembly that rotationally drives a well drilling bit during drilling. and the stabilizer comprises a hollow cylinder of rigid pliable material extending centrally throughout its length and having an opening substantially corresponding to the external cross-sectional dimensions of said elongated cylindrical assembly. It has a main body.
The opening is adapted to receive therein a longitudinal portion of an elongated tubular assembly. The hollow cylindrical body has an open gap extending along its length, the gap extending from the outer portion of the hollow cylindrical body to the inner opening. Means made of a rigid material are arranged on the outer part of the hollow cylindrical body and rest against the inner surface of the borehole to stabilize the elongated cylindrical assembly within the borehole during rotational drive of the drilling bit. I'm starting to let them do it. a clamping engagement on the outer surface of the cylindrical assembly adjacent one side of the gap to engage the hollow cylindrical body and extending across the gap to engage the other side of the gap and tightening and extending the cylindrical body; Means is provided for causing the matching. This is adapted to counter the torque and linear forces applied to the stabilizer in response to engagement of said leaning means with the inner surface of the bore.

The hollow cylindrical body has a relatively small wall thickness relative to the outer transverse diameter of the body, which allows the rigid flexible material to be deflected by the tightening means. , the stabilizer is tightened in the longitudinal direction of the elongated cylindrical assembly.

The open gap of the hollow cylindrical body extends over its entire length in some embodiments and is substantially parallel to the longitudinal axis, while in other embodiments it extends substantially parallel to the longitudinal axis. Stretch at an angle. In selected embodiments, the longitudinally extending open gap is substantially wedge-shaped.

Means made of a rigid material disposed on the outer portion of the hollow cylindrical body includes a plurality of elongated blades spaced apart from each other and extending substantially in the direction of the longitudinal axis of the hollow cylindrical body. Each blade is shown having an outwardly facing ridge for resting on the inner surface of the borehole and forming a groove with the adjacent blade. The groove is suitable for providing a passageway for drilling fluid between the hollow cylindrical body and the inner surface of the borehole.
Preferably, the open gap extends along the length of one blade. The surface of the end of each blade preferably includes a wear-resistant material. In one example, the extension of each blade is substantially parallel to the longitudinal axis of the hollow cylindrical body, and in another example, the extension of each blade is substantially parallel to the longitudinal axis of the hollow cylindrical body. It is shaped like an angle. In another example, the extension of each blade is substantially helical.

In the disclosed embodiments, the fastening means suitable for engaging the hollow cylindrical body includes a fastener device, which in selected embodiments includes a plurality of threaded bolts and a plurality of engagement bolts. a nut and a plurality of pairs of alignment holes disposed adjacent the gap. This bolt preferably has a fitted head, and the opening is
Preferably with a pick-up hole, each nut and snap-head bolt are respectively arranged in an opening with a pick-up hole.

In order to retain the nut in the aperture with the pick-up hole, an interference fit is preferably formed between the outside of the nut and the inside of the aperture, so that tightening the bolt will force the nut to is drawn into and engaged therein with an opening having a pick-up hole. The nut is thus held in the opening with the receiving hole independently of the bolt connection. Similarly, a flexible retaining member is placed in the pick-up hole adjacent the bolt head to retain the bolt in the opening independent of the connection to the nut. The retaining member is then engaged in the aperture with the pick-up hole in such a way that the bolt head cannot axially leave the aperture.

These and other features of the invention will become more apparent from the following description of selected embodiments, when considered in conjunction with the accompanying drawings and claims.

Although the present invention will be described with reference to embodiments, it is not limited by the shapes in the accompanying drawings.
Also, the same instruction number shall indicate the same part.

Next, the drawings will be explained in detail. A surface drilling rig 10 (FIGS. 1 and 2) is supported at an offshore location and is adapted to drill a plurality of boreholes 12. Hole bottom positions 14A and 14B are located in oil zones, or oil layers A and B, respectively, and the depth of the oil layer changes as the depth of the bottom of the borehole changes. One of the perforations 12' is a vertically extending perforation, while the remaining perforations extend at an angle to the vertical. The bottom locations of each borehole are arranged in a grid pattern and extend over a square area of approximately 4 square miles, or 10,000 feet on each side. In order to orient the bottom position of the perforations to various positions, the angle of each perforation is different and adjusted by the use of stabilizers.
While the depth of the water is several hundred feet or more,
It is noted that the depth of oil layer B is 14,000 m or more.

The drill string shown in FIG. 3 consists of an interconnected drill collar 20 and a drill bit connected to the lowermost drill string member. Each drill collar is, for example, 30 feet long, has an outside diameter of approximately 8 inches, an inside diameter of approximately 2 inches, and a weight of approximately 5000 degrees. Since the depth of the borehole is up to 14,000 feet or more, the weight of the drill collar is supported at its top, since it would otherwise destroy the drill string. That is, a predetermined weight corresponding to the weight of the drill collar is supported by the drilling bit. All but a small portion of the drill collar remains in tension. A number of drill collar segments, for example 20, are supported by the drilling bit and provide the necessary weight for drilling. Neutral point 24
defines where the tension ends. Below the neutral point, the drill collar is loaded in compression.

The angle at which the borehole is drilled is determined in part by the weight of the drill collar, which causes the bending to occur. The angle is also determined by the position of the stabilizer 26 on the drill collar. As the stabilizers are placed closer together along the drill collar assembly, the flex of the drill collar increases and an increased angle in the drilling direction is achieved. According to the invention, the stabilizer includes:
It can be placed at any position on the drill collar so that a precise angle for drilling can be obtained.

FIG. 4 shows how the stabilizer determines the bending of the drill collar and therefore the drilling angle. In the distance L1 between the stabilizers,
There is a large amount of deflection in the drill collar, thus increasing the drilling angle. The larger the spacing of the stabilizers, for example spacing L2, the less deflection and therefore a smaller drilling orientation angle is obtained. The spacing of the stabilizers can also be varied so that the magnitude of the drilling angle can be varied.
This may be desirable if it is determined, for example by magnetic information, that the drilling will deviate from the target point.

Turning now to FIG. 5, the stabilizer 26 is shown as being of unitary construction with a helical hole or slot 28 extending along the length of the stabilizer. Stabilizer 26 has an axial opening 30 that has an inside diameter sufficient to allow stabilizer 26 to slide over drill collar 20 . Separated spiral blade 3
2 are provided in large numbers to engage with the boreholes. (Figures 7 and 8). The gap or groove between each blade allows fluid to flow between the surface of the perforation and the body surface 33 between the blades. The blade is on the side part 3
4 and an outer peripheral edge portion 35. The outer peripheral portion 35 of the blade engages the inner surface of the borehole (seventh
), thereby stabilizing the drill collar.
In addition, the blade acts as a reamer to open the borehole or keep it open. Since the blade is susceptible to wear, hard particles 36, such as tungsten carbide, tungsten chips, or stellite material, are embedded around its periphery.

The blades are evenly spaced around the stabilizer periphery, with only blades 32A and 32B being located adjacently. Blades 32A and 32B
each have a plurality of holes 37 therein, the opposing pairs thereof being aligned. Head fitting bolts, i.e. screws 38 and each nut 4
0 (Figures 6 and 8 and 9) is used to secure this stabilizer to the drill collar.
When the head-fitting bolt is tightened against the nut, the stabilizer with the gap is drawn together, that is, the end blades 32A and 32B are brought together, and the stabilizer is tightened around the drill collar 20.

The stabilizer shown in FIG. 5 has a plurality of longitudinally overlapping blades 32, which means that when the stabilizer is in a borehole, the borehole is
This is to allow engagement with a plurality of blades at each longitudinal position. More specifically, longitudinal position 44A engages one blade 32, while axially distant longitudinal position 44B engages the last blade 32.
It is engaged with 2A.

As shown in FIG.
0 is inserted into the receiving hole portion 52 of the opening 37.
The nut 40 is splined and dimensioned to form an interference fit in the pick-up portion 54 of the aperture 37 in the blade 32. That is, bolt 3
8 is tightened against the nut 40, the splines of the nut are worn or reamed as the nut is drawn into the opening, and the nut, by virtue of the interference mounting, closes in the pick-up opening 54.
It becomes locked inside. As a result, bolt 3
If any of the bolts 8 fail, both halves of the failed bolt are retained in their respective apertures and do not dislodge from the stabilizer. The plurality of bolts 38 allows a large, evenly distributed clamping force to be applied to the outer surface of the drill collar by the split stabilizer. Additionally, the bolt can be conveniently installed with conventional hand tools.

According to the embodiments shown in FIGS. 10 to 12,
Stabilizer 60 has an axially extending open gap or gap 62 that extends linearly. The stabilizer 60 has spaced straight blades 64 that also fit into the stabilizer opening 6.
It extends in the axial direction with respect to 0. The stabilizer blades are spaced apart to allow drilling fluid to pass therebetween. The stabilizer 60 is secured to the drill collar 20 in the same manner as described above for the stabilizer 26 with bolts 38 and nuts 40. The stabilizer 60 has a groove 66 on the sides of the blades 64A, B on opposing sides away from the gap 62.

Drill collars currently manufactured can have an outside diameter of approximately 8 inches, for example. The stabilizer is also sized to fit these dimensions. However, after a period of use, the drill collar develops an outside diameter of 7 7/8 inches or 7 3/4 inches due to wear. Tubular shims 68 can be utilized to mount the same stabilizer to these reduced diameter collars. This shim is cylindrical with an axially extending crack 70. For a 7 3/4 inch collar, the shim thickness may be approximately 1/8 inch, for example, while the slit 70 may be approximately 1/2 inch wide.
The shim 68 is initially placed around the drill collar 20 and then the stabilizer is placed around the shim. Tightening of bolt 38 causes the stabilizer to tighten directly against the outer surface of the drill collar.

The radial clearance between the stabilizer and the drill collar, before the stabilizer is tightened to the drill collar, is approximately 1/2 inch for an 8 inch outside diameter drill collar and approximately 7 7/8 inches. It is approximately 1/8 inch compared to the drill collar that has been polished down.

The stabilizer shown in FIGS. 5 to 8 has spiral blades 32 that overlap. In other words, the straight line extending in the longitudinal direction of the stabilizer is
Intersects with at least two different blades. In another, the stabilizer blades can extend in a spiral but not overlap. The overlap ensures that the blade always engages the inner surface of the borehole. If there is no overlap, or if straight blades are used, the blades will intersect disjointly against the walls of the borehole.

To permit magnetic information collection about the drilling, the drill collar can be a non-magnetic material such as stainless steel, Monel material, etc. The stabilizer according to the invention works equally well whether the material is magnetic or non-magnetic. this is,
This is because the clamping engagement according to the invention allows the stabilizer to be fixed without the risk of severe corrosion.

The stabilizer according to the invention can be easily mounted on a drill collar and can be mounted in any axial position. In addition, the stabilizer according to the invention will not separate from the drill collar even if the stator is not fully activated, since the stabilizer is a one-piece, cylindrical piece that surrounds the drill collar. It is. Moreover, the nuts and bolts that fasten the stabilizer to the drill collar will not fall out during drilling if they fail or become loose.

The advantages of the invention, as well as variations and modifications to the disclosed embodiments thereof, will be apparent to those skilled in the art. It is the intention of the applicant to include by the claims all such changes and modifications that may be made as embodiments;
Those selected for the purpose of disclosure are merely illustrative.

[Brief explanation of the drawing]

FIG. 1 depicts an offshore drilling rig located above water and multiple boreholes that may be drilled from a single location on the rig. FIG. 2 relates to the arrangement of perforations produced by the apparatus of FIG. FIG. FIG. 3 shows vertically extending perforations by solid lines and directional perforations by dashed lines, to which a plurality of stabilizers are fixed. FIG. 4 is a schematic diagram showing the relationship between stabilizer spacing and drill collar bending. FIG. 5 is an external view of the stabilizer according to the present invention. FIG. 6 is a cross-sectional view of the stabilizer of FIG. 5 taken along line 6--6, showing the stabilizer clamped onto the drill collar. FIG. 7 is an elevational view showing the stabilizer of FIG. 4 being secured to a drill collar placed during drilling; FIG. 8 is a cross-sectional view of FIG. 7 taken along line 8--8. FIG. 9 is a partial view taken along line 9--9 of FIG. 7, showing the retaining bolt. FIG. 10 is an external view of a stabilizer according to another example of the present invention. FIG. 11 is an external view showing that the stabilizer of FIG. 9 is fixed to a drill collar. FIG. 12 is a cross-sectional view taken along line 12--12 of FIG. 10: Surface drilling device, 12: Drill hole, 20: Drill collar, 26: Stabilizer, 30: Axial opening, 32A, 32B: Blade, 40: Nut.

Claims (1)

[Scope of Claims] 1. A stabilizer for use in an elongated cylindrical assembly for rotationally driving a well drilling bit in a borehole, comprising: (a) a hollow body made of a hard material and having a wall portion; a cylindrical body having a central opening extending longitudinally, the opening corresponding to the dimensions of the outer cross-section of the elongated cylindrical assembly, and having a constant length; (b) a hollow cylindrical body adapted to accommodate a shaped aggregate and of a thickness such that the wall portion is flexible; means arranged in a wellbore drilling bit for rotationally driving a cylindrical assembly extending substantially along the length of the hollow cylindrical body and resting on the inner surface of the borehole; (c ) engaging said leaning means made of a rigid material adjacent to one side of said gap and engaging said leaning means adjacent to the other side of said gap for crossing said gap; means for tightening a hollow cylindrical body which is extendable and deflectable by changing the dimensions of the opening into a clamping engagement with an outer surface of the elongated cylindrical assembly, the clamping engagement comprising: so as to be able to be fixedly positioned over the length of the elongated cylindrical assembly;
and corresponding means for said leaning means to engage an inner surface of the perforation to resist torques and vertical forces applied to the stabilizer. 2. In the stabilizer according to 1 above, the hollow cylindrical body has a relatively small wall thickness compared to the outer cross-sectional dimension of the body, and the relatively small wall thickness engages the hollow cylindrical body to stabilize the stabilizer. A stabilizer which is made deflectable by means which make it tighten in the longitudinal direction of an elongated cylindrical assembly. 3. The stabilizer according to 1 above, wherein the hard material of the hollow cylindrical body is made of a metal material. 4. The stabilizer according to 1 above, wherein the gap extends substantially parallel to the longitudinal axis of the hollow cylindrical body. 5. The stabilizer according to 1 above, wherein the gap extends substantially at an angle to the longitudinal axis of the hollow cylindrical body. 6. The stabilizer according to 1 above, wherein the gap extends substantially in a spiral shape. 7. In the stabilizer according to 1 above, the leaning means formed of a rigid material and arranged on the outer part of the hollow cylindrical body are arranged at a distance from each other and extend substantially in the direction of the longitudinal axis of the hollow cylindrical body. extending, having a plurality of elongated blades, each blade having an outwardly facing ridge adapted to rest on the inner surface of the bore to form a groove with respect to the adjacent blade; a stabilizer adapted to provide a passageway for drilling fluid between an outer portion of the hollow cylindrical body and an inner surface of the borehole. 8. The stabilizer according to 7 above, wherein the surface of the end of each blade includes an abrasion resistant material. 9. The stabilizer according to 7 above, wherein the extension of each blade is substantially parallel to the longitudinal axis of the hollow cylindrical body. 10. The stabilizer according to 7 above, wherein the extension of each blade forms a certain angle with respect to the longitudinal axis of the hollow cylindrical body. 11. The stabilizer according to item 7 above, in which the extension of each blade is substantially spiral. 12. The stabilizer according to 1 above, wherein said means suitable for engaging with the hollow cylindrical body are arranged in a plurality of threaded bolts, a plurality of nuts to be combined, and a blade, said plurality of a stabilizer having a plurality of pairs of aligned holes for receiving bolts and nuts of the stabilizer. 13. The stabilizer according to 12 above, wherein the bolt has a fitting head. 14. The stabilizer according to item 13 above, wherein the opening has a pick-up hole, and each nut and the bolt having a fitting head are respectively arranged in the opening having the pick-up hole. 15. In the stabilizer according to item 14 above, the nut and the opening with the receiving hole form an interfering fitting so that tightening the bolt forces the nut into the opening with the receiving hole. A stabilizer adapted to be retracted into engagement, whereby said nut is retained independently of the bolt in an opening having a pick-up hole. 16 In the stabilizer according to 15 above, a flexible holding means is provided in the opening having the pick-up hole adjacent to the head into which the bolt is fitted, and the holding means is configured to elastically fit into the opening having the pick-up hole. a stabilizer which is resiliently engaged, thereby preventing said bolt from moving axially out of said opening; 17. The stabilizer according to 1 above, wherein the hollow cylindrical body and the leaning means made of a rigid material are made of a non-magnetic material. 18. The stabilizer according to 17 above, wherein the hollow cylindrical body and the leaning means made of a rigid material are made of stainless steel. 19. The stabilizer according to 18 above, wherein the hollow cylindrical body and the leaning means made of a rigid material are made of Monel alloy. 20. The stabilizer according to item 15 above, wherein the opening having the pick-up hole is formed by one gap extending in the direction of the opening. 21. The stabilizer according to 1 above, wherein the gap is open and intersects with the outside of the stabilizer.