GB2458527A

GB2458527A - A high expansion anchoring or stabalizing device

Info

Publication number: GB2458527A
Application number: GB0805365A
Authority: GB
Inventors: Tony Laplante
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-03-25
Filing date: 2008-03-25
Publication date: 2009-09-30
Anticipated expiration: 2028-03-25
Also published as: GB2458527B; GB0805365D0

Abstract

A pressure activated expanding anchoring or stabilizing device has blades 11 that are offset from the device axis. The blades 11 extend to centralize the device within wellbore tubing 23. The blades 11 may be extended by hydraulic pressure and are biased to a closed position (fig 1) by a spring 5. Alternatively a pressure activated expanding device comprises blades 11 that are specially formed to engage a variety of tubing 23 diameters. Preferably the blades 11 have serrated teeth to aid contact with the tubing 23 and are curved along their leading edge enabling contact with various tubing diameters. The blades 11 may remain extended when pressure is lowered and are pushed back into their closed position (fig 1) when retrieved from the wellbore.

Description

Title: High Expansion Anchoring and Stabilisation Device Backgound: Flow operated Hydraulic Anchors are generally used during operations in oil and gas welts where a toot assembly needs to be secured and held centrally, down hole within a tubular member The anchor provides a means of anchoring the toot string at any given depth ensuring that none of the down hole tools shift, either rotationally or axially, during an operation.

Historically these anchors do not give a high enough expansion for anchoring below limited restrictions and any designs which can allow the anchor to be deployed below a restriction tend to have convoluted flow paths through the toot.

Statement of Invention:

To over come this, the present invention provides a straight, through bore and also the high expansion capabilities required to pass though, although not necessarily, small restrictions and then open out and engage into large bores. This is achieved via diametrically opposed blades which pivot about hinge pins which are located through the Housing and within the Inner Mandrel of the device. Because of the nature of this design it can also be used as a hydraulic stabiliser when furnished with suitable blades.

Advantages: The uninterrupted through bore reduces the amount of turbulence through the tool which can occur with convoluted flow paths. By reducing the turbulence, it then reduces the erosive properties of the fluid and so prolongs tool life.

The high expansion anchoring blades enables the tool to pass through restrictions which are not much larger than the tool OD. The hardened blades then open out and bite into the inside diameter of the tubular. The blade is designed to grip inside a range of bores eliminating the need to change out blades for different sizes.

Introduction to drawings:

The attached drawings show how this current invention functions.

Figure 1 -Shows the assembled Anchor.

Figure 2 -Shows the anchor in the open position.

Figure 3 -Shows an external view of the Anchor.

Figure 4 -Shows an end view of the Anchor with blades extended Figure 5-Shows an end view of the tn-blade Anchor with blades extended Figure 6-Shows the Piston Figure 7-Shows the Blade.

I

Detailed Description:

This invention relates to a hydraulically activated expanding device to be used as a) An anchoring device or b) a tubular bore stabiliser. The Anchor provides a mechanical means of anchoring and locating a body centrally within a tubular member. The through bore of the tool is isolated from the Annulus. It operates via the application of pressure. This pressure can be generated by pressuring against a blanked off sub within the bottom hole assembly or as a result of fluid flow through a restriction below the anchoring device. The application of this pressure causes a piston to act against a spring, the movement of these pistons resutts in said blades being rotated about hinge pins and pivoted out of the tool body until they engage the tubular inside diameter or further movement of the pistons is prevented by a spacer tube When pressure or flow ceases the Compression spring drives the pistons back to their start position. In doing so the anchor blades are automatically retracted back within the tool body. The operation of the anchor is further explained in detail below With reference to figure 1. This shows a cross-section view of the Anchor. The Anchor consists of a Top Sub (1), which has a box thread (26) looking up for attachment to upper work string. The Top Sub (1) is attached via a thread to the Housing (10) The Inner Mandrel (6) is located within the inside diameter of the Top Sub (1) and sealed with an 0-ring (2). The void between the Housing (10) and the Inner Mandrel (6) has a Spacer Tube (4) and a Compression Spring (5) contained therein. The Upper Piston (9)is in direct contact with the Compression Spring (5). The pockets in the Upper Piston (9) contain the Anchor Blades (11). The Anchor Blades (11) are held in place with Hinge Pins (7). These Hinge Pins (7) pass through drilled holes in the Housing (10) through the Upper Piston (9), through the Anchor Blades (11) and locate in flat bottom holes in the Inner Mandrel (6). The Hinge Pins (7) are held in place with Circlips (8) The Lower Piston (12) butts against the Upper Piston (9). The pockets in the Lower Piston (12) contain the Anchor Blades (11). The Anchor Blades (11) are held in place with Hinge Pins (7). These Hinge Pins (7) pass through drilled holes in the Housing (10), through the lower Piston (12), through the Anchor Blades (11) and locate in flat bottom holes in the Inner Mandrel (6). The Hinge Pins (7) are held in place with Circlips (8).

The Lower Piston (12) maintains a seal with the Housing (10) via an 0-ring (14) and with the Inner Mandrel (6) with an 0-ring (13). This forms the piston area which actuates the tool The Bottom Sub (17) is threaded to the bottom end of the Housing (10) and sealed with an 0-ring (16). The Inner Mandrel (6) is centralised and axially retained within the Bottom Sub (17). The Bottom sub has a pin thread (27) looking down for attachment to lower work string.

Figure 2 shows another cross-section of the anchor but this time in the open position. Internal pressure, as a result of flow or static pressure, in the inside diameter (20) of the tool acts on the piston void (18) via the communication ports (15) in the inner mandrel (6). This internal pressure acting on said piston area, produces an axial force. When this force is greater than that of the Compression Spring (5) the Upper and Lower Pistons (9 & 12) move axially within the tool As fluid contained within the compression spring void (21) is compressed it is vented to the tool annulus via relief ports (3). As the pistons move, the ramp (19) within each piston will contact the Anchor Blade (11) tips. Continued movement of the pistons results in the Anchor Blades (11) pivoting about the Hinge Pins (7), riding up the ramp (19) and the blades exiting the anchor Housing (10) through slots (22) cut therein This motion of the pistons will stop when the Blades either contact the tubing inside diameter (23) or the Upper Piston (9) bottoms out against the Spacer Tube (4).

An external view of the Anchor can be seen in figure 3. Here it is shown with the Anchor Blades (11) extended and contacting the inside diameter of the tubing (23). Here the slots (22) which house the blades (11) are clearly visible. An end view of the Anchor showing the blades extended is shown in figure 4. This shows how the blades are configured in the 4 blade version of the tool.

The tool can be configured with 3 blades on the same plane; this can be seen in figure 5.

When flow stops or pressure is released the Compression Spring (5) pushes the pistons (9 &12) back to their start position (Refer to fig.2). In doing so, as each piston approaches its neutral position, a tang (24) on each piston contacts a recess (25) on each blade. As the pistons continue to move back to their neutral position the action causes the blades (11) to be pulled back into the body of the anchor, here the blades will remain until flow or pressure is re-introduced to the device. The tang (24) and recess (25) can be clearly seen in figures 6 & 7. Figure 1 shows how the tang (24) and recess (25) on each piston and blade assembly match up and thus prevent the blades from opening when the tool is inactive