Patent Application
20230022591
The present inventions are directed to swivels configured for a casing ram as opposed to an annular blowout preventer (BOP) and allowing for differential pressure during operation as high as 10,000 pounds per square inch (psi) or more.
Circulating a well under pressure is usually accomplished by closing the annular BOP to seal on the workstring. The friction between the annular seal and the workstring creates high axial loads that complicate rotating and reciprocating the workstring. At the end of a frac pack treatment the workstring and downhole service tool must be reciprocated upward under pressure to reverse circulate proppant laden fluid out of the workstring. The added friction when stripping through the annular BOP complicates precise downhole service tool movement and positioning. Use of a slick outer diameter workstring and grease can reduce friction between the annular BOP and workstring; however, friction can still be significant.
Another concern is the pressure rating of the annular BOP. In deepwater frac packs, reverse circulating pressures can potentially exceed the annular BOP rating. When it is anticipated that the annular BOP pressure rating will be exceeded, the frac pack design must be more conservative to mitigate a high pressure situation.
Prior art devices such as the Mako MAPTool™ and Deltascope® are described in, for example, U.S. Pat. No. 10,988,989 which is incorporated herein by reference. Such prior art devices facilitate rotating and reciprocating a workstring in a well that is under pressure. Such tools generally have an outer housing and a slick inner mandrel. The slick inner mandrel is sealed inside the outer housing. The outer housing is positioned and sealed in an annular BOP. Thus, the tool is static while allowing the inner mandrel to rotate and reciprocate with minimal friction even at high pressure differential. In this manner, the annular BOP seals on the outer housing of the device to reduce friction.
While these prior art devices may address the axial load concern of stripping through the annular BOP, they unfortunately do not address the pressure rating limit of the annular BOP. It would be desirable if new tools and methods could be designed that would allow higher differential pressures such that pressure during operations are not limited to the rating limit of an annular BOP which may be only 5,500 psi. It would be advantageous if such new tools and methods allowed for aggressive frac pack treatments to maximize production rate and ultimate recovery from a well. It would further be desirable if such new tools and methods facilitated reverse out operations following a frac pack for both efficiency and effectiveness.
The novel tools and methods described herein accomplish at least one or more of the aforementioned needs. That is, the tools and methods of the present application may allow for differential pressure during operation as high as 10,000 psi or more. They also may allow for aggressive frac pack treatments and facilitate reverse out operations.
In one embodiment, the application pertains to a swivel insertable into a casing ram of a workstring. The swivel comprises an inner mandrel 10 having an upper end section and a lower end section. The upper end section is configured to be operably connectable and rotatable with an upper workstring section and the lower end section is configured to be operable connected to a lower workstring section. The inner mandrel comprises a longitudinal passage forming a continuation of a passage in the workstring. The outer housing has an outer diameter and a length configured to fit a casing ram while allowing the function of associated casing shear rams and variable bore rams. The outer housing is configured to seal the inner mandrel inside the outer housing. The inner mandrel is configured to slide up and down within the outer housing and rotate within the outer housing. In this manner, use of the novel tool within a casing ram may allow for a differential pressure during operation as high as 10,000 psi or more.
In another embodiment, the inner mandrel further comprises a locator recess. This locator recess may be configured to facilitate placement of the swivel within a casing ram.
In order to describe the manner in which the above-recited and other advantages and features can be obtained, a more particular description of the subject matter briefly described above will be rendered by reference to specific embodiments which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments and are not therefore to be considered to be limiting in scope, embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
Exemplary embodiments of the invention will now be described in order to illustrate various features of the invention. The embodiments described herein are not intended to be limiting as to the scope of the invention, but rather are intended to provide examples of the components, use, and operation of the invention.
As shown in
In contrast to the prior art tool that is used in the annular blowout preventer, the present application pertains to a tool that is configured to be placed within the casing rams 140 as shown in
One advantage of using a fixed casing ram vs. the annular BOP is the ability to go to higher differential pressures during operation. For example, the maximum differential pressure when using the annular BOP may be 5,500 psi. When using the fixed casing ram, the differential pressure could go as high as 10,000 psi. The higher differential pressure capability is beneficial particularly when reverse circulating proppant laden fluid out of a workstring following frac pack operations.
The increased pressure rating afforded by designing the instantly described tools so that they may be placed in a fixed casing ram instead of the annular BOP allows for aggressive frac pack treatments to maximize production rate and expected ultimate recovery from the well. The tools of this application employed in a casing ram may also facilitate reverse out operations following a frac pack and/or maintain weight down on tool during a frac pack.
In another embodiment, the inner mandrel of the tool in
In some embodiments the following process steps may be employed:
