GB2566249A

GB2566249A - Method for cleaning casings using well fluid

Info

Publication number: GB2566249A
Application number: GB1709658.7A
Authority: GB
Inventors: Paul Fraser John; Bodman Cherish; Fong Jason
Original assignee: Coretrax Technology Ltd
Current assignee: Coretrax Technology Ltd
Priority date: 2017-06-16
Filing date: 2017-06-16
Publication date: 2019-03-13
Anticipated expiration: 2037-06-16
Also published as: GB201709658D0; GB2566249B

Abstract

A tool 1 for cleaning the internal diameter of a casing 12 using well fluid includes a barrier 2 and at least two cleaning elements 5, 7, a chamber in which well fluid is accelerated and a jetting device 6. The cleaning elements may include brushes 5, scrapers 7, magnets, wiper rings or fins. A funnel 8 may divert fluid into the velocity chamber, towards a nozzle 10 of the jetting device 6. The internal profile 9 of the cavity may be rotational, for example a spiral, conical or fin profile, creating a vortex within the body and causing the tool 1 to rotate. An anti-rotational plate 4 may prevent transfer of torque to the plug 2. The nozzles 10 of the jetting device 6 may provide an oscillating or rotational jet. A method of using the tool 1 to clean the casing 12 with well fluid is also disclosed.

Description

A METHOD FOR CLEANING CASING

FIELD OF THE INVENTION

The present invention relates to a wellbore cleaning element and more specifically a method of cleaning the internal diameters of pipe, primarily casings, using the well fluid. The pipe can comprise a drill pipe, tubular or conduit used in oil and gas drilling and recovery operations. The invention relates to a process of cleaning and removing residual debris from such pipe using well fluid and a lateral movement of the cleaning element in the wellbore, without the need to pump.

BACKGROUND OF THE INVENTION

Once a wellbore has been drilled it is typically lined with a casing to preserve the shape of the wellbore and provide a conduit for the transportation of fluids to surface. It is important that the wellbore is clean to ensure that future operations are not compromised and therefore the presence of debris in the wellbore can present a problem. There are many potential sources for downhole debris including but not limited to cuttings from drilling or milling applications, drill pipe connection and casing wear swarf and metallic debris from components used in previous operations.

The presence of debris in the wellbore can be detrimental to operations, presenting a risk of damage to highly complex completions, damage to downhole equipment and can disrupt packers or plugs from setting. The build-up of debris can also present restrictions in the wellbore and the debris presence can affect the production of hydrocarbons. Smaller debris such as mud residues can prevent a good bond being established between packer or plug elements and the casing wall. In some operations such as well abandonments it is desirable to place a cement plug, these mud residues can prevent the cement from bonding correctly with the casing wall and allow gas migration.

There are various methods of removing the debris from the wellbore: larger particles can be removed by circulating and/or increasing the velocity of annular fluid to retrieve the debris to surface. It is not uncommon for an accumulation of casing scale or similar debris to develop on the inner diameter of casings and this too can present problems for future operations. This scale/debris can be dislodged using a cleaning element, such as a scraper or brush, and then circulated to surface and removed from the wellbore.

The cleaning of the inner diameter of casings is required to prevent a build-up of debris deposits and this is typically done through the use of a scraper or brush tool as mentioned above. Fluid circulation, rotation and reciprocation are often used to enhanced cleaning results.

Typically, these cleaning tools are run in a dedicated trip into the wellbore however a cleaning run can add significant time to the operation and is costly to the operator. In some instances, it would be preferred to incorporate the cleaning run into another run to complete two operations simultaneously. Furthermore, during circulating large amounts of debris, fluid interfaces and slops can be returned to surface. The disposal associated with the fluid interfaces and slops are costly, both to the operator and environment.

Therefore a design is required which can provide a method of cleaning the inside diameter of casings providing a well suspension method and reducing circulation in one trip to assist in reducing rig time and waste deposits to environment.

The following invention allows the internal walls of the casing to be cleaned whilst running in hole utilising the wellbore fluid within the tool to create a jetting action and removing the need for circulation. The invention will also allow for a disposable cleaning element combined with the setting of a bridge plug or packer in a single run.

SUMMARY OF THE INVENTION

Accordingly to a first aspect of the present invention, there is provided a tool for cleaning the internal diameter of a casing using well fluid comprising:

A robust barrier device mounted on a disposable body

Two cleaning elements mounted on the disposable body

A velocity chamber

A jetting device

Preferably, all aspects of the plug will be made from drillable or soluble materials.

The barrier setting device can be but is not limited to a plug or packer and can be mounted at the top of the tool to provide a plug for permanent abandonment or temporary suspension. This can be placed in the same run, after cleaning activities have been completed. Preferably, the barrier will be hydro-mechanically set to minimise cement disturbance when placing a cement plug on top of the bridge plug or packer. Additionally, the plug will encompass a lower connection to allow assembly to the other components of the proposed invention. Optionally, the plug or packer can be used to perform cementing operations.

The invention will feature a lower body which will house the cleaning elements and jetting features. The cleaning elements will be mounted on the body and can include but not limited to a combination of brushes, scrapers or magnets. For example, a brush above the jetting device and scraper below.

Additionally, the lower body will house the velocity chamber, which will increase the velocity of the well fluid whilst running in hole. The velocity chamber can be but is not limited to a 'coned' sleeve design inside the lower body. The velocity chamber should be but is not limited to a design as such that the lowermost internal diameter is larger than that of the uppermost part of the chamber to create a velocity chamber. Optionally, there may be a diverter feature or similar at the top of the velocity chamber to aid in directing the flow of fluid to the jetting nozzles. Optionally, the internal profile of the velocity chamber may feature a rotation profile, this may include but is not limited to a spiral profile or fins. As the fluid passes through the body, a vortex effect will be created and this will cause the tool to rotate, allowing more effective cleaning by the elements. Optionally, an anti-rotation plate may be installed between the plug or packer and the lower body to prevent transmission of torque to the barrier.

Additionally, the lower body should also incorporate a funnel at the lowermost part. This assists in diverting the well fluid through the tool to be used for jetting. Further, this funnel can be used to prevent large debris from entering the internal of the tool. Optionally, this may include additional features to direct maximum fluid through the tool this may be but not limited to external fins which may be manufactured from rubber and can also provide an additional cleaning method, by cleaning the inner diameter of the casings whilst run in hole.

The jetting device will preferably be situated between the two chosen cleaning elements. The jetting device will comprise of a number of jetting nozzles which will preferably be designed to create a jet of well fluid and can be but not limited to an oscillating jet or rotating jet. The well fluid velocity will preferably be increased through the use of the lower velocity chamber and an internal velocity chamber within the individual jets. Preferably the device will include four jetting nozzles. Optionally, the number of jetting nozzles can be increased or decreased. Additionally, each nozzle will comprise of two semi-circular parts with an internal profile. The two parts are assembled to create one jetting nozzles and can be held together through the use of a locking system. This may be but is not limited to a locking key. The profile in the assembled jetting nozzle can feature but is not limited to a velocity chamber and an exit port and may optionally include a rotating disc feature. The velocity chamber increases well fluid velocity again before it exits from the exit port. The jetting nozzles can be installed into the jetting device and should feature a means to ensure they are secured in place which may be but not limited to mating threads on the external of the nozzle and the internal of the housing allowing the nozzles to be screwed into place. Optionally, the nozzles may be designed to provide a sweeping or rotating effect.

Additionally, if it is chosen to incorporate three cleaning elements then the jetting device would preferably be located below the top cleaning element. The lower body will also house the lower velocity chamber, which will increase the velocity of the well fluid.

Running in with the tool will divert well fluid through the velocity chamber and will be directed to the jetting device. The fluid will be sped up further through the nozzle velocity chamber before exiting the nozzle as a powerful jet which may be but not limited to oscillating or rotating to assist the two cleaning elements with removing debris from the internal diameters of the casing.

The various aspects of the present invention can be practiced alone or in combination with one or more of the other aspects, as will be appreciated by those skilled in the relevant arts. The various aspects of the invention can optionally be provided in combination with one or more of the optional features of the other aspects of the invention. Also, optional features described in relation to one example can optionally be combined alone or together with other features in different examples of the invention.

Various examples and aspects of the invention will now be described in detail with reference to the accompanying Figures. Still other aspects, features and advantages of the present invention are readily apparent from the entire description thereof, including the Figures, which illustrate a number of exemplary aspects and implementations. The invention is also capable of other and different aspects and implementations, and its several details can be modified in various aspects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. Furthermore, the terminology and phraseology used herein is solely used for descriptive purposes and should not be constructed as limiting in scope.

Language such as including, comprising, having, containing, or involving, and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers or steps. Likewise, the term comprising is considered synonymous with the terms including or containing for applicable legal purposes.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way of example only and not in any limitative sense, with reference to the accompanying drawings, in which:

Figure 1 is a schematic front view of the preferred cleaning tool and shows fluid flow paths;

Figure 2A and Figure 2B are cross-sectional schematic views of a jetting nozzle profile;

Figure 3A and Figure 3B are views of the velocity chamber in the lower body

DETAILED DESCRIPTION OF THE DRAWINGS

Figure 1 shows a schematic front view of the preferred embodiment of the cleaning tool 1. Preferably, the cleaning tool 1 consists of a barrier device 2, such as a plug or packer, a lower connection 3, an anti-rotational plate 4and the lower body. The lower body comprises of a cleaning element 5 e.g. a brush, a jetting device 6, and a second cleaning element 7, preferably a scraper. Optionally the fluid funnel 8 can be used to divert flow into the device. Additionally, the internal profile 9 of the lower body 11 is preferably of a 'coned' profile and leads to the jetting device 6. The jetting device encompasses the oscillating jetting nozzles 10. Figure 1 shows the tool in the casing 12. The fluid funnel fins 13 provide additional cleaning of casing internal walls and also assist in diverting fluid into the velocity chamber. Arrows have been used to show flow path of the well fluid, with smaller arrows being used to show faster moving fluid.

Figure 2A shows a cross sectional view of an oscillating jetting nozzle 10. The semi-circular portion shown in figure 2A and 2B would be assembled together with a second semi-circular portion, preferably through use of a locking key 14 to provide a single oscillating jet. The assembled jetting nozzle would ideally be fitted to the jetting device using the thread 15. The fluid will enter the nozzle through the velocity chamber 16 and will gain velocity as it travels through the chamber 16and into the fluid directional chamber 17 before being expelled from the jet through the exit port 18 creating an oscillating jet. Optionally, as shown in Figure 2B a rotating disc 19 may be used to provide rotating jets.

Figure 3A shows the velocity chamber 9 of the lower body and the diverter 20 to direct flow out to the nozzles. Figure 3A shows a spiral profile 21 inside the velocity chamber 9 to encourage rotation of the lower cleaning element. Figure 3B shows a finned 22 cone.

Claims

1. A tool to aid in the cleaning of casings utilising well fluid comprising:

Cleaning elements mounted on a disposable body to clean the inner diameter of the casing,

A velocity chamber to increase fluid speed

A fluidic funnel to direct well fluid through the chamber

A jetting device incorporating jetting nozzles

A barrier device to create a seal with the casing

2. A cleaning element as detailed in claim 1, can comprise of but not limited to brushes, scrapers, magnets, wiper rings, fins and or combinations of any of the aforementioned cleaning elements.

3. The body of the lower cleaning element will comprise of a jetting device situated between two cleaning elements as detailed in claim 1 and 2 where jetting nozzles can provide but not limited to an oscillating jet or a rotational jet.

4. As detailed in claims 1 and 3, a oscillating jetting device comprising of

A number of fluidic oscillating jets and

A lower velocity chamber

5. As detailed in claim 1 and 4, incorporating a velocity chamber in the lower body of the tool to accelerate fluid, where the chamber may be but not limited to a 'coned' sleeve design with a reducing ID towards the top of the tool.

6. A velocity chamber as detailed in claims 4 and 5 which directs well fluid whilst running in hole allowing wellbore fluid to increase in velocity while passing towards the oscillating jets.

7. As detailed in claim 1 and 4, fluidic oscillating jets where each jet comprises two semicircular profiles which fit together to form a single jet.

8. As detailed in claim 7, where each profile may incorporate a locking mechanism such as but not limited to a locking pin.

9. A jetting nozzle as detailed in claim 7 may have a mechanism to secure into the jetting device such as but not limited to a thread or screw device.

10. A jetting nozzle as detailed in claim 7 with an internal profile which can be but is not limited to a velocity chamber and an oscillating nozzle or exit port.

11. The internal profile as claimed in claim 10 may include a sweeping or rotational design for the nozzle.

12. A tool as claimed in claim 1 which utilises the fluid displacement whilst running in hole to harness the energy and increase velocity to provide a jetting action from the jetting device.

13. A tool as claimed in claim 1 including a fluid funnel to direct the fluid flow into the velocity chamber.

14. A fluid funnel as outlined in claim 13 which can also present a method of reducing large debris from entering the tool.

15. A fluid funnel as outlined in claims 13 and 14 which may incorporate additional features such as but not limited to a fin which provides contact with the casing to assist in cleaning and maximise fluid flow through tool.

16. A barrier device outlined in claim 1, which is located at the upper section of the cleaning element and will ideally comprise of, but not limited to, a hydro-mechanical set bridge plug with an integrated setting tool.

17. A barrier device outlined in claim 1 which may be set by alternative means including but not limited to wireline set.

18. The plug device outlined in claims 1,15 and 16 which can be used for but not limited to use for providing abandonment or suspension options or conducting cementing operations through.

19. The lower velocity chamber described in claim 6 may have an internal profile such as but not limited to a spiral, fin or rotational profile. This can create a fluid vortex and result in rotating the tool.

20. The tool in as claimed in claim 1, which can rotate due to internal profile outlined in claim 19, can also incorporate an anti-rotation plate between the cleaning element and the plug to prevent the transmission of torque to the plug or packer.

21. A tool as claimed in claim 1 which incorporates directional flow paths in the design to divert the fluid from the velocity chamber to the nozzle.