Plug concealment and diversion tool

A tool for capturing and retaining a pump down plug or ball which has been released from equipment above in a well bore, concealing the pump down plug from subsequent flow of fluid or other material through the tool, and diverting flow from a normal circulation port toward a bypass port through the tool. The pump down plug seats in, and closes, the circulation port, where the pump down plug is then retained by a tubular receptacle. Increased fluid pressure then shears the tool body loose from its housing, moving it downward to a position lower in the housing. This opens the path through which the pump down plug was released from above. A further pressure increase can be used to open the bypass port through the tool body. When the tool body is released from its first position, a diverter can close over the tubular receptacle and divert movement of fluid and other material away from the area of the circulation port and toward the bypass port.

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is in the field of equipment which operates by means of closing a downhole port by pumping a plug, ball, or other device downhole with the drilling fluid, cement, or other fluid.

2. Background Art

It is well known in the art of oil and gas well drilling to operate or actuate downhole equipment by pumping a plug, ball, or other device downhole with the drilling fluid, cement, or other fluid. The term pumpdown plug, pumpable plug, or other such term, as used herein, is intended to include all such devices, whether plugs, balls, or other items.

When it is desired to actuate a piece of downhole equipment, such as a cementing valve, it is common to pump a plug downhole to close off, and sometimes seal, a port through which fluid is being circulated. The closing of this port can then be used to create an increased fluid pressure above the port, to actuate the device. After actuating the downhole equipment in this manner, it is sometimes desired to release the pumpable plug from the port and restore circulation through, the port. When a pumpable plug is released in this manner, it typically proceeds farther downhole. Unless such a released plug is properly captured and retained, it can interfere with, or even prevent, subsequent operations in the well bore below the location from which the plug was released.

It is known to capture such a released plug in a perforated tube below the downhole equipment which the plug was originally used to actuate. Capturing the released plug in a perforated tube has the advantage of allowing fluid flow through the perforations and to the well bore below the capture point. However, a perforated tube will not allow the performance of some subsequent operations which may be desirable, below the capture point, such as wireline operations. Further, if it is necessary to pass other equipment through the plug capture point in the well bore, such as for the purpose of undertaking remedial operations deeper in the well bore, the presence of the captured plug in the perforated tube will prevent such operations. In these situations, if the perforated tube is present, it would have to be removed before passing any equipment beyond the plug capture point.

It is desirable, therefore, to have a method and apparatus for capturing a pumpable plug which has been released, and for allowing the passage of fluid and equipment beyond the plug capture tool to a deeper location in the well bore.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a method and apparatus for guiding a released plug to an open circulation port in a plug capture tool, thereby closing the circulation port. Increased fluid pressure above the plug capture tool then shears the tool body loose from its housing, allowing the tool body to move to a lower point in the housing where it comes to rest against a shoulder or some other retention feature. This removes the tool body from the inlet port through which the plug was released, allowing free flow or movement of fluid and other material through the open inlet port and past the captured plug, which is retained in place in the circulation port, by means such as a tubular plug guide. Further increasing the pressure can shear loose a closure plug which may be mounted in a bypass port in the tool body. Thereafter, fluid and other material which has passed through the inlet port and around the captured plug can move or flow through the bypass port to a location downhole from the tool body. When the tool body is sheared loosed from its attachment to its housing, and the tool body then moves farther downhole in the housing, this also allows a diverter means, such as a pivoting baffle, to move into place above the plug guide and above the captured plug. This baffle assists in retaining the captured plug in the plug guide. This baffle also diverts the flow or movement of fluid and other material, such as intervention or workover equipment, away from the area around the circulation port and toward the bypass port.

The novel features of this invention, as well as the invention itself, will be best understood from the attached drawings, taken along with the following description, in which similar reference characters refer to similar parts, and in which:

DETAILED DESCRIPTION OF THE INVENTION

As shown inFIG. 1, the tool10of the present invention includes a tool housing12, a slidable tool body14, and a plug guide tube28. The housing12can be mounted as part of a work string, below other equipment (not shown) which will ultimately release a pumpable plug or ball through a plug duct PD, such as a production tube. The tool body14is slidably mounted within the housing12, and releasably held in a first position by a releasing device such as a tool body shear pin16. It can be seen that this first position of the tool body14is a distance above an internal shoulder13within the housing12.

A circulation port18is provided through the tool body14, from above to below. A bypass port20is also provided through the tool body14, from above to below. In the starting configuration, the bypass port20may be closed or plugged by a closure such as a shearable plug22. Alternatively, the bypass port20may be open. When present, the shearable plug22can be held in place, for instance, by a bypass plug shear pin24. A seat26can be provided in the throat of the circulation port18.

A device for guiding a pumpdown plug or ball to the circulation port18, such as a guide tube28, can be attached to the tool body14above the circulation port18, extending upwardly from the tool body14. A material diverting means, such as a pivotable baffle30can be mounted to the upper end of the guide tube28. As seen in the run-in configuration of the tool shown inFIG. 1, the upper end of the guide tube28is aligned with, and receiving, the lower end of the plug duct PD. In this configuration, a pumpdown plug which may be released from above will pass through the plug duct PD and out its lower end, which constitutes an inlet port40into the tool of the present invention, and into the plug guide tube28. Rather than being at the outlet of a tubular element, such as a production tube, the inlet port40to the tool of the present invention could be found in any kind of equipment which might release a pumpdown plug or ball into the tool. In the configuration shown, where the tool is fed by a tubular element PD, the pivotable baffle30is necessarily pivoted away from the upper end of the guide tube28, lying alongside the plug duct PD, to allow the lower end of the plug duct PD to communicate with the upper end of the guide tube28. The pivotable baffle30can be biased by spring force, fluid flow, or gravity, as is known in the art, toward a position over the upper end of the guide tube28.

FIG. 2shows the configuration of the tool when a pumpdown plug PP has been released from above to pass through the plug duct PD and the tool inlet port40, into the guide tube28. Having come to rest in the seat26of the circulation port18, the pumpdown plug PP now stops flow of fluid and any other movement of any other material through the circulation port18. In fact, where the bypass port20is plugged with a shearable plug22, this prevents such movement of material past the tool body14in any way. Since the flow of fluid is stopped, this causes hydraulic pressure above the tool body14to increase, at the election of the operator. When the pressure above the tool body14is selectively raised to a sufficient level, the tool body shear pin16shears, and the tool body14slides downwardly relative to the housing12, until it comes to rest against the housing shoulder13, where it is retained against further downward movement. Alternatively, where the shearable plug22is not used, the operator can simply increase fluid flow through the bypass port20to a sufficiently high level to cause the differential pressure across the bypass port20to shear the shear pin16.

In either case, the shifted position of the tool body14is shown inFIG. 3. It can be seen that, when the tool body14slides downwardly, the upper end of the guide tube28separates from the inlet port40and moves downwardly. This allows any additional material, whether fluid or solid, including equipment, to pass through the inlet port40and into the housing12, without passing into the guide tube28. Where the inlet port40is in the lower end of a tubular element such as the plug duct PD shown, the lower end of the tubular element may move laterally as shown, once free of the upper end of the guide tube28.

When the tool body14and the guide tube28are selectively moved downwardly a sufficient amount, it can be seen that this allows the pivotable baffle30to pivot over the upper end of the guide tube28. As mentioned above, the baffle30may be biased by spring force, fluid flow, or gravity to aid in this selective pivoting of the baffle30. As can be seen, the baffle may also come to rest against the housing12or against other structure. When the baffle30pivots into the position above the upper end of the guide tube28, it acts as a material diverter, diverting material which may pass through the inlet port40away from the upper end of the guide tube28and the area of the circulation port18, and toward the area of the bypass port20.

Where the shearable plug22is present, a further increase in hydraulic pressure above the tool body14can selectively cause the shear pin24to shear, allowing the shearable plug22to be forced out of the bypass port20, as shown inFIG. 4. Where the shearable plug22is not used, the bypass port20is already open. In this configuration, any material, whether fluid or debris or equipment, which passes through the inlet port40will be allowed to pass through the bypass port20, as shown by the arrows, depending of course on the size of any solid particles or equipment. This bypassing movement of the material through the tool body14is aided by the diversion caused by the baffle30. Therefore, fluid and equipment can be passed through the tool body14after the pumpdown plug PP is captured and concealed.

While the particular invention as herein shown and disclosed in detail is fully capable of obtaining the objects and providing the advantages hereinbefore stated, it is to be understood that this disclosure is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended other than as described in the appended claims.