Swivel Apparatus For Fixed Casing Ram

Abstract

The present application pertains to a swivel insertable into a casing ram. The swivel comprises an inner mandrel having an upper end section and a lower end section configured to be operably connectable and rotatable with an upper workstring section and a lower workstring section, the inner mandrel comprising a longitudinal passage forming a continuation of a passage in the workstring. An outer housing is configured to seal the inner mandrel inside the outer housing. The outer diameter of the outer housing and the length of the outer housing is configured to fit a casing ram. In contrast to prior art tools placed within annular blowout preventers which have limited differential pressure ranges, the instant device allows for differential pressure during operation as high as 10,000 psi or more. The instant devices also may allow for aggressive frac pack treatments and facilitate reverse out operations.

Description

TECHNICAL FIELD

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.

BACKGROUND AND SUMMARY

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.

BRIEF DESCRIPTION OF THE DRAWINGS

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:

FIG. 1 shows a tool for rotating and reciprocating a workstring in a well that is under pressure and configured to be employed in a casing ram as opposed to an annular blowout preventer (BOP).

FIG. 2A shows a prior art tool that is configured to be in an annular blowout preventer (BOP).

FIG. 2B shows a tool of the present application which can be employed in a casing ram.

FIG. 3 shows a modification to a top portion of the prior art tool.

DETAILED DESCRIPTION

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.

FIG. 1 shows a tool of the present application for rotating and reciprocating a workstring in a well that is under pressure. The tool generally has an inner mandrel 10, an upper seal 20, outer housing 30, and lower seal 40. The tool is designed such that the outer diameter area 50 of the housing fits within casing rams as opposed to the prior art tools that are sized and configured to fit where an annular blowout preventer closes and seals.

As shown in FIG. 1, tools of the present application generally have an outer housing 30 and a slick inner mandrel 10. The slick inner mandrel 10 is sealed inside the outer housing 30. The outer housing 30 is positioned and sealed in a casing ram. The sealing occurs in outer diameter area 50. Thus, in contrast to prior art tools the tools of the present application, among other differences, have an outer diameter of the outer housing and a length of the outer housing configured to fit a casing ram. The tool are further configured to allow the function of associated casing shear rams and variable bore rams. In this manner the casing ram seals on the outer housing of device to reduce friction while allowing differential pressures during operation as high as 12,500 psi or more.

FIG. 2A shows the prior art tool of FIG. 1 within an annular blowout preventer 100 wherein blind shear rams 110, casing shear rams 120, upper variable bore rams 130, casing rams 140, lower variable bore rams 150, and test rams are present below the annular blow out preventer.

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 FIG. 2B.

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.

An Exemplary Embodiment of a Tool

FIG. 3 shows the swivel of the present application within the casing ram 140. Unlike the prior art tools Mako MAPTool™ and Deltascope® that are configured to fit within an annular blowout preventer, the tool of FIGS. 1 and 3 has an outer diameter of the outer housing 30 which is configured to fit a casing ram. While such outer diameters may vary depending upon the casing ram and application, a typical outer diameter of the outer housing 30 may be from about 9.5 to about 10 inches and preferably 9 ⅝ inches as opposed to 9.18 inches for prior art tools configured for an annular blowout preventer. Similarly, the length of the outer housing of the tool of FIGS. 1 and 3 varies from the prior art in that the length is configured to fit a casing ram. Thus, length of the outer housing of the instant tools is generally shorter than prior art tools. The aforementioned modifications allow for the tools of the instant application to be employed within a casing ram without substantially interfering with the function of components such as associated casing shear rams and variable bore rams.

In another embodiment, the inner mandrel of the tool in FIG. 3 further comprises a locator recess configured to facilitate placement of the swivel within a casing ram. The depiction on the left side of FIG. 3 is an exploded depiction of the top of the mandrel of the device shown in the casing ram. As shown, there is a recessed portion wherein the outer diameter is smaller. This recessed portion or offset may facilitate locating the outer housing of the tool across the casing rams in a desired position. That is, the recessed portion may be configured to fit within the annular blowout preventer. The size of the outer diameter of the mandrel and the recessed portion may vary depending upon the application. In some embodiments, the outer diameter may be about 7 inches while the recessed portion may be about 5 ⅞ inches. That is, the outer diameter at the recessed portion may be from about 80 to about 85% of the mandrel outer diameter.

In some embodiments the following process steps may be employed:

• Build special Inner Mandrel with locator recess
• Close Annular BOP on recess
• PU to against recess upset to space Outer Housing across Casing Rams
• Close Casing Rams
• Open Annular BOP
• Slack-off to release Inner Mandrel latch
• Run in hole ±60'
• Close Test Rams
• Perform pressure test on Deltascope® Tool between Test Rams and Casing Rams
• Continue running in hole

Claims

1. A swivel insertable into a casing ram of a workstring, the swivel comprising:

an inner mandrel having an upper end section and a lower end section configured to be operably connectable and rotatable with an upper workstring section and a lower workstring section, the inner mandrel comprising a longitudinal passage forming a continuation of a passage in the workstring; and

an outer housing having an outer diameter and a length and wherein the outer housing is configured to seal the inner mandrel inside the outer housing;

wherein the inner mandrel is configured to slide up and down the outer housing and rotate within the outer housing; and

wherein the outer diameter of the outer housing and the length of the outer housing is configured to fit a casing ram while allowing the function of associated casing shear rams and variable bore rams.

2. The swivel of claim 1 wherein the inner mandrel further comprises a locator recess configured to facilitate placement of the swivel within a casing ram.