VIBRATING TOOL

Abstract

A vibrating tool comprising a hammer and valve that oscillate axially inside a housing to produce vibrations solely in response to fluid flow through the tool at an operating flow rate. The valve is supported by a spring that resists compression until a minimum operating flow rate is achieved, and hammer is also spring-loaded. When the valve strokes down and engages the hammer, flow through the hammer is restricted. Increased fluid pressure pushes the hammer down away from the valve, resulting in a sudden decrease in pressure, allowing both the hammer and valve to rebound and create vibrational impacts. The cycle repeats continuously as long as an adequate flow rate is maintained.

Description

FIELD OF THE INVENTION

The present invention relates generally to downhole tools and, more particularly but without limitation, to vibrating tools for reducing friction drag in coiled tubing applications.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an exploded, side elevational view of a bottom hole assembly comprising a vibrating tool in accordance with the present invention.

FIG. 2 is a longitudinal sectional view of a vibrating tool made in accordance with a first embodiment of the present invention.

FIGS. 3 and 4 are enlarged, sequential sectional views of the tool shown in FIG. 2.

FIG. 5 is an enlarged sectional view showing the valve of the tool shown in FIG. 2.

FIG. 6 is an enlarged sectional view showing the hammer of the tool shown in FIG. 2.

FIG. 7 is a longitudinal section view of a vibrating tool made in accordance with a second embodiment of the present invention.

FIG. 8 is an uphole end view of the hammer member of the embodiment of FIG. 7.

FIG. 9 is an enlarged sectional view of the hammer member of the tool shown in FIG. 7.

FIG. 10 is an enlarged sectional view of the valve and hammer sections of the tool shown in FIG. 7.

FIG. 11 is a further enlarged sectional view showing the valve member of the tool shown in FIG. 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Coiled tubing offers many advantages in modern drilling and completion operations. However, in deep wells, and especially in extended reach non-vertical wells, the frictional forces between the tubing string and the borehole wall while running the coiled tubing sometimes cause buckling and even lockup of the tubing string.

Vibrating tools have been developed for use in coiled tubing conveyed assemblies to reduce the frictional drag of the tool string. These vibrating tools facilitate operations in directional drilling applications and significantly increase the depth that can be achieved during the conveyance of the bottom hole assembly (“BHA”).

The present invention provides a friction-reduction tool that offers many advantages. The vibrating mechanism is driven solely by controlling fluid flow through the tool; neither axial movement of the tubing string nor the downward pressure of the tubing on the housing is required. The structure of the tool is simple and sturdy, providing a reliable tool that is economical to build and maintain and easy to redress. The body of the tool has a relatively shorter overall length so it is easier to negotiate through tight curves in the well bore. The vibrating mechanism is completely enclosed in a solid housing, so there are no external parts to fall into the tools below. The tool may include a bypass area for a logging conductor wire and is compatible with e-coil operations. The vibrations generated in the tool are sufficient to reduce friction between the BHA and the wellbore but of low enough intensity to avoid damage to other tools in the BHA. The friction-reduction tool of the present invention can be employed in applications such as plug-drilling, junk milling, new-well bore drilling, fishing, logging, perforating, including abrasive perforating, and any other operation in a conveyed situation where coiled tubing or a workstring is used to transport the tools into a lateral well bore.

Turning now to the drawings in general and to FIG. 1 in particular, there is shown therein a bottom hole assembly or “BHA” comprising a vibrating tool in accordance with the present invention. The vibrating tool, designated generally at 10, is shown installed in the BHA, designated generally at 12. The BHA 12 may comprise a wide assortment of tools. By way of example only, the BHA 10 shown in FIG. 1 comprises a motor head assembly 14, a downhole motor 16, and flat bottom junk mill 18. The vibrating tool 10 is shown in the BHA 12 between the motor head assembly 14 and the motor 16. However, it will be appreciated that the number and type of tools, and the relative position of the vibrating tool 10 within the BHA, may be varied according to the specific well conditions.

Turning now to FIGS. 2-6, a first embodiment of the vibrating tool of the present invention will be described. As illustrated in FIG. 2, the tool 10 comprises a solid, enclosed housing 20, that is, there are no external moving parts. The structure of the housing 20 may vary, but in the preferred embodiment, the housing comprises a top sub 22, a housing body 24, and a bottom sub 26, which are threadedly connected. The uphole end 28 of the top sub 22 may be provided with a box joint 30, and the downhole end 32 of the bottom sub 26 may be provided with a typical pin end 34 for interconnection with the other tools in the BHA 12. Seals, such as O-rings, are used at these joints and elsewhere in the tool, and are all designated by the reference number 36. The housing 20 defines a flow path, identified by the arrow 40, extending completely through the tool 10 so that fluid flowing through the coiled tubing (not shown) can pass through the tool into the tools below it in the BHA 12.

Referring still to FIG. 2 and now also to FIGS. 3 and 4, the tool 10 comprises a vibrating assembly 42 that includes a hammer 44 and a valve 46. The hammer 44 and valve 46 are contained within a generally tubular vibrator housing 50, which may comprises a top sub 52, a barrel 54, and a bottom sub 56. The top sub 52 is connected to the downhole end 58 of the housing top sub 22, so that impacts delivered to the vibrator housing 50 will be transmitted to the housing 20.

The hammer 44 is supported inside the vibrator housing 50 in the flow path 40 of the tool 10 to stroke axially. In this embodiment, the vibrating assembly 42 incorporates part of the hammer mechanism shown and described in U.S. Pat. No. 6,315,063 entitled “Reciprocating Rotary Drilling Motor issued on Nov. 13, 2001 to Leo a. Martini. This patent is incorporated herein by reference.

In the Martini patent, the hammer delivers repetitive impacts to a drill bit at the end of a drill string. In the tool 10 of the present invention, the hammer 44 “floats” inside the vibrator housing 50. More specifically, the hammer 44 is resiliently supported on a spring, such as the compression spring 60. Although a helical compression spring is shown, the term “spring” as used herein broadly denotes any form of resilient support. For example, the spring alternately may be Belleville washer springs, rubber elastomer blocks, or some form of compressed air or liquid.

A stack of shims (not shown) may be used below the spring 60 to allow fine-tuning of the resistance offered by the spring 60. Additionally, as seen in FIG. 4, a filter plate 62 (FIG. 4) may be placed at the bottom of the spring 60 to capture any debris that may pass through the tool 10.

Referring now also to FIGS. 5 and 6, the hammer 44 generally comprises a bottom member 64, fixed to the downhole end 66 of a tubular body or mandrel 68, and a top member 70 fixed to the uphole end 72 of the mandrel. The hammer 44 defines a flow path 74 through its length that is continuous with the flow path 40.

As best seen in FIG. 6, the bottom member 64 of the hammer 44 has an impact transmitting surface, which may take the form of an annular shoulder 76 on the uphole end 78 of the bottom member 64. The impact transmitting surface 76 is configured to engage and thereby cause a percussive impact on an impact receiving surface on the housing 20 of the tool 12. The impact receiving surface may be the downhole end face 82 of the bottom sub 56 of the vibrator housing 50.

The hammer 44 is supported in the flow path 40 of the tool 10 to stroke axially and to provide in its stroke cycle an impact to the housing 20 of the tool. To that end, the top member 70 and mandrel 68 are slidably supported inside the vibrator housing 50, so that the top member acts as a piston inside a hydraulic chamber 80 formed by the vibrator housing 50. Now it will be apparent that as the hammer 44 moves up and down in the vibrator housing 50, the impact transmitting surface 76 on the bottom member 64 will repetitively and percussively impact the impact receiving surface 82 on the bottom sub 56 of the vibrator housing 50, and these impacts will be transmitted to the tool housing 20 to cause vibrations in the tool 10.

Axial movement of the hammer 44 is driven by fluid flowing through the flow paths 40 and 74 and the chamber 80 and is controlled by the valve 46. Again, the valve 46 in this embodiment is substantially that disclosed in the above-identified Martini patent, so its structure and operation will only be summarized.

As shown in FIG. 5, the valve 46 comprises a valve stem 90 slidably mounted in the valve support 92 non-movably fixed to the inside of the vibrator housing 50. Fluid ports 94 in the valve support 92 allow fluid to pass through the support. The downhole end of the valve head 96 defines a valve contact face 97 that is engagable with a valve seat 98 formed in the uphole end of the top member 70 of the hammer 44 that forms a hammer contact face 99.

When the valve stem 90 is on the upstroke, the valve 46 is “open” with the valve head 96 separated from the seat 98 allowing unrestricted flow of fluid through the valve support 92 and into the flow path 74 of the hammer 44. When the valve 46 is in the downstroke, with the valve head 96 seated in the seat 98, fluid flow is restricted, allowing a fluid pressure differential to build in the chamber 80 above the support 92. In this embodiment, closure of the valve and hammer results in a total blockage or occlusion of flow through the flow path in the hammer 44. However, as used herein in relation to the fluid flow, “restricted” includes reduced flow as well as complete occlusion of flow.

The valve stem 90 is biased or “uploaded” in the open or upstroke by a valve return spring, such as a helical compression spring 100, which is selected to resist downward movement of the stem until a selected operating flow rate is achieved. A second valve lift-off spring 102 may be included. As indicated previously in relation to the compression spring 60, other types of springs may be employed.

Now it will be understood that as the flow rate of fluid through the tool 10 is increased, the pressure of the fluid flow eventually will overcome the resistance of the return spring 100 and the valve stem 90 will shift downwardly until the head 96 nests in the seat 98, occluding fluid flow therethrough. This is referred to herein as the “operating flow rate.” An orifice 104 may be mounted in the flow path above the valve stem 90 to prevent the fluid stream from directly impacting the upper end of the valve stem.

Closing of the valve results in a sudden increase in fluid pressure in the chamber 80 above the valve support 92, which continues to move the valve stem 90, and the hammer 44 driven by it, down until the valve stem reaches the end of its stroke distance. This occurs when the lift-off spring 102 is completely compressed forming a stop to limit the stroke distance of the valve 44.

At this point, continued pressure through the ports 94 continues to move the top member 70 of the hammer 44, separating the valve head 96 from the seat 98 and reestablishing unrestricted flow through the flow path 74. This sudden decrease in fluid pressure allows the valve stem 90 to return to its neutral position and also permits the hammer 44 to rebound. As the hammer rebounds, the impact transmitting surface 76 on the bottom member 64 of the hammer 44 hits the impact receiving surface 82 on the bottom the bottom sub 56 of the vibrator housing 50, causing the vibratory impact. As long as the minimum operating flow rate is maintained, the cycle will repeats itself, creating vibrations in the tool.

Referring still to FIGS. 3-6, yet another feature of the vibrating tool will be described. A secondary fluid path 108 through the tool 10 may be provided by making the outer diameter of the vibrator housing 50 slightly smaller than the inner diameter of the tool housing 20 to create an annulus 110. Ports 112 (FIG. 3) in a reduced diameter portion 114 of the top sub 22 allow fluid to enter the annulus 110, and similarly ports 116 (FIG. 4) in the bottom member 64 of the hammer 44 allow fluid to exit the annulus and reenter the flow path 40. This secondary flow path allows the use of logging conductor wire for e-coil applications.

Directing attention now to FIGS. 7-11, a second embodiment of the inventive vibrating too will described. This embodiment, designated herein by the reference number 10A, may be used in the BHA 12 of FIG. 1 in place of the tool 10.

Like the tool 10, the tool 10A comprising a solid housing 200 that is completely enclosed, that is, has no external moving parts. The housing 200 comprises a top sub 202, a housing body 204, and a bottom sub 206. These members are threadedly connected with O-rings 208 to provide a fluid tight flow path 210 therethrough.

The vibrator assembly 218 comprises a hammer 220 resiliently supported on a spring 222 with a flow path 224 continuous with the flow path 210 in the housing 200. The bottom sub 206 includes a spring receiving portion 228 (FIG. 10) that supports the spring 222. A filter plate 230 and/or shims (not shown) may be included at the base of the spring 222.

A piston-type valve 234 is supported in the housing 200 above the hammer 220. A valve spring 236 is captured between an annular shoulder 238 formed on the inside of the housing body 204 and a shoulder 240 formed on the outside of the valve 234, as best seen in FIG. 11. A flow path 242 extends through the valve 234 and is continuous with the flow path 210 through the housing 200 and the flow path 224 in the hammer 220.

The valve 234 is slidably received in a narrow diameter portion 244 of the housing body 204. Thus the valve 234 is configured to stroke axially. The upstroke ends when the uphole end 246 of the valve 234 meets the downhole end 248 of the top sub 202. A second annular shoulder 250 on the outside of the valve 234 acts as a stop when it meets the shoulder 238 (FIG. 11) to limit the travel of the valve.

As it strokes, the valve 234 acts on the hammer 220 to control fluid flow. To that end, the uphole end 252 of the hammer 220 defines a hammer contact face 254, and the downhole end of the valve 234 defines a valve contact face 256. In the neutral position, illustrated in FIG. 11, the hammer and valve contact faces 254 and 256 oppose each other but are spaced a distance apart forming a gap 258. The hammer 220 is provided with flow control ports 260 in its uphole end 252 that opens on the hammer contact face 254 and communicates with the flow passage 224 through the hammer 220.

Now it will be appreciated that, when the valve 234 strokes down, the valve contact face 256 will engage the hammer contact face 254. The flow control ports 260 are sized and positioned so that this contact closes off flow through the ports, restricting fluid flow and resulting in a sudden rise in the fluid pressure inside the valve 234. Preferably, the hammer contact face 254 is configured so some of its surface area remains exposed when the valve 234 closes the ports 260, as this allows the fluid pressure inside the valve to act directly upon the hammer 220 as well as on the valve 234.

In this way, the sudden increase in pressure will push the hammer 220 further down away from the valve 234, reopening the ports 260.

When unrestricted flow through the ports 260 is reestablished, there is a sudden decrease in pressure. This permits the valve 234 and the hammer 220 to rebound on their respective compression springs 236 and 222. Because the resistance of the hammer spring 22 is greater than the resistance of the valve spring 236, the hammer contact face 254 impacts the valve contact face 256, creating a vibratory impact. Thus the hammer contact face 254 serves as impact transmitting surface and the valve contact face 256 serves as an impact receiving surface.

As indicated, the hammer 220 strokes axially in the housing 204 as it is acted upon by the stroking valve 234 and the fluid pressure in flow path 210. The length of the downstroke of the hammer 220 is determined by force of the fluid and resistance of the spring 222. In its uppermost position, the annular shoulder 266 formed on the outer perimeter of the hammer of the hammer 220 abuts the annular complimentary shoulder 268 formed on the inside of the housing 204, as best seen in FIGS. 10 and 11. However, while the tool is vibrating, the hammer 220 may not rebound far enough to cause the hammer shoulder 266 to impact the housing shoulder 268. While in some instances this interface may serve as a point of vibratory impact, the “chattering” of the tool more preferably is caused by the impact of the hammer contact face 254 against the valve contact face 256 in the rebound phase of the cycle.

Now it will be apparent that the vibrator assembly 218 of the embodiment 10A, like the tool 10, is operated entirely by regulating fluid flow through the tool. Both the hammer and valve oscillate axially inside the closed housing in response to fluid flow at an operating flow rate to create gentle but effective vibrations downhole to facilitate advancement of the BHA. The rapidity of the vibrations can be controlled by regulating the flow rate.

As used herein, phrases such as forwards, backwards, above, below, higher, lower, uphole and downhole refer to the direction of advancement of the pipe string.

The embodiments shown and described above are exemplary. Many details are often found in the art and, therefore, many such details are neither shown nor described. It is not claimed that all of the details, parts, elements, or steps described and shown were invented herein. Even though numerous characteristics and advantages of the present inventions have been described in the drawings and accompanying text, the description is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of the parts within the principles of the inventions to the full extent indicated by the broad meaning of the terms. The description and drawings of the specific embodiments herein do not point out what an infringement of this patent would be, but rather provide an example of how to use and make the invention.

Claims

1. A vibrating tool for use in a bottom hole assembly, wherein the tool comprises a housing defining a flow path through the tool, and the tool further comprising a hammer and a valve both resiliently supported inside a solid housing for oscillating axial motions solely in response to fluid flow through the tool at an operating flow rate.

2. The vibrating tool of claim 1 wherein the tool further comprises a vibrator housing forming a fluid chamber inside the tool, wherein the hammer comprises a piston like member axially movable inside the fluid chamber, wherein the hammer has a flow path therethrough, wherein the valve comprise a valve stem axially movable in the fluid chamber to open and close the flow path through the piston like member of the hammer.

3. The vibrating tool of claim 2 wherein the housing has an impact receiving surface, wherein the hammer further comprises a bottom member having an impact transmitting surface configured to repeatedly impact the impact receiving surface as the hammer oscillates.

4. The vibrating tool of claim 3 further defined as having an uphole end and a downhole end, herein the vibrator housing and the tool housing are configured to form an annulus therebetween defining a secondary flow path through the tool, wherein the uphole end has an inlet to provide communication from the flow path into the annulus, wherein the downhole end has an outlet to providing communication from the annulus into the flow path.

5. The vibrating tool of claim 1 wherein the resilient support for the hammer is a helical compression spring.

6. The vibrating tool of claim 5 wherein the resilient support for the valve is a helical compression spring.

7. The vibrating tool of claim 6 wherein the resistant of the hammer spring is greater than the resistance of the valve spring.

8. The vibrating tool of claim 1 wherein the resilient support for the valve is a helical compression spring.

9. The vibrating tool of claim 1 wherein the tool housing defines a fluid chamber continuous with the flow path, wherein the valve comprises a first tubular piston movable axially in the fluid chamber and having a valve contact face, wherein the hammer comprises a second tubular piston movable axially in the fluid chamber and having a hammer contact face, wherein the hammer further comprises a flow path extending through the hammer, and wherein the valve contact face and the hammer contact face are configured so that when the valve contact face engages the hammer contact face fluid flow through the flow path in the hammer is restricted and so that when the hammer contact face is spaced a distance from the valve contact face fluid flow through the flow path in the hammer is unrestricted.

10. A vibrating tool comprising: a tool housing defining a fluid-tight flow path;a hammer supported in the flow path of the tool to stroke axially therein in response to fluid flow through the tool and having a hammer contact face, wherein the hammer defines a hammer flow path extending from the contact face and continuous with the flow path of the tool housing;a valve supported in the flow path of the tool to stroke axially therein in response to fluid flow through the tool and having a valve contact face, wherein the valve defines a valve flow path extending from the valve contact face and continuous with the flow path of the tool housing and the hammer flow path;a valve return spring configured to resist downward movement of the valve until at least an operating flow rate through the flow path of the tool is achieved;a hammer spring configured to resist downward movement of the hammer, the hammer spring having a greater resistance than the valve spring;wherein the valve is positioned in the housing above the hammer so that when the tool is in the neutral position the valve contact face opposes and is spaced a distance from the hammer contact face permitting unrestricted flow from the valve flow path to the hammer flow path and so that in response to an operating flow rate the valve strokes downward against the resistance of the valve spring to bring the valve contact face into engagement with the hammer contact face; andwherein the hammer and valve are configured for performing a repetitive vibratory cycle in which, when the hammer and valve contact faces engage, flow through the hammer flow path is restricted to produce increased fluid pressure on the hammer contact face to stroke the hammer down against the resistance of the hammer spring, which in turn separates the contact faces causing a pressure decrease, which then allows the hammer and the valve to rebound causing an impact within the housing to vibrate the tool, the cycle repeating for so long as the operating flow rate is maintained.

11. The vibrating tool of claim 10 further comprising a stop for limiting the downward axial movement of the valve.

12. The vibrating tool of claim 11 wherein the valve comprises a valve stem axially supported in a valve support, wherein the tool further comprises a second valve lift-off spring, and wherein the downward travel of the valve is limited by the valve lift-off spring.

13. The vibrating tool of claim 11 wherein the tool housing defines an annular shoulder surrounding the valve, wherein the valve comprises a tubular piston having an outer diameter that defines an annular shoulder configured to engage the annular shoulder on the housing to limit the downward travel of the valve.