Patent Application
20120151707
The field of the invention is the use of a debris removal tool with an articulated pickup coupled with a camera to allow a visual indication of the debris being sucked into the pickup hose.
Debris in a borehole has many sources. Milling up equipment creates a large quantity of debris as does removal of scale from a tubular string. Various tools have been developed to capture such debris within a tool body or an annular passage surrounding the body. Motive force for capturing the debris comes from pumps at a well surface. In one design the pumped fluids are the motive force for an eductor that pulls debris laden fluid into the lower end of a housing and through the mechanism of slowing the velocity in the housing allows some debris to settle in a retention volume and smaller debris to hit an internal screen as the remaining fluid gets sucked into the eductor. This tool type is illustrated in U.S. Pat. No. 6,276,452. Other similar tools are illustrated in U.S. Pat. Nos. 7,478,687; 6,176,311; 6,250,387 and US Publication 2002/0162655.
While such tools create the fluid movement to capture debris moving in the main bore, the ability to pick up debris in crevices, recess and side pockets is more problematic. These tools can create some vacuum at their lower end to induce debris to flow into the tool from a main wellbore but the orientation and level of vacuum generated at the tool lower end is seldom enough to induce debris out of recesses such as those in an open blowout preventer. Some operators pull the blowout preventer stack after a milling job to clean or confirm that the recesses in the preventer are not cluttered with debris to the point that the preventer will not close when required to prevent a blowout.
Some cleaning approaches involve pressurized fluid through a nozzle impacting the debris in the hope of dislodging it and later capturing it as illustrated in U.S. Pat. No. 6,390,105 or U.S. Pat. No. 6,325,305. There are several issues with this technique. One is that the fluid blast can actually impact the debris in the recess rather than dislodging it. Another issue if there is to be a separate trip to collect debris after jetting it loose is that the loosened debris can settle back into the crevice in between the trips. Multiple trips are also time consuming and therefore expensive. Some operators still pull the blowout preventer after such procedures as a milling operation to be sure that the recess spaces in the blowout preventer are clear of debris. This is a very expensive procedure in subsea applications.
Another concern is the ability to see from the surface that debris is being removed from the recess or pocket in question. Cameras that can be articulated to get close to otherwise inaccessible locations have been used as shown in U.S. Pat. No. 5,689,734 (heat exchanger or turbine blade inspection) and U.S. Pat. No. 4,991,006 (underground utility pipelines). Some applications in downhole use incorporate a fiber optic cable with auxiliary lines to keep the lens clear, as shown in U.S. Pat. No. 5,275,038. These are single purpose tools for inspection and other tools have to be run later to accomplish a repair if a problem section is spotted.
The present invention employs a debris removal tool with an articulated inlet that allows axial displacement of a pickup hose as well as extension and retraction and rotation about a longitudinal axis. The pickup hose assembly can be anchored near the desired location and extension and retraction can occur with raising or lowering the debris removal tool. A camera can be mounted in or near the pickup hose to assist in placing the end of the hose and for visual confirmation that the debris has been sucked out. Those skilled in the art will better appreciate the various aspects of the invention after a review of the detailed description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention can be found in the appended claims.
A debris removal tool has a lower end pickup hose into which debris laden fluid is pulled when there is circulation through the debris removal tool from the surface. An anchor near the open end of the hose stabilizes the lower end near a recess or groove from which debris is to be removed. Once the anchor is set the hose can be extended or retracted as well as rotated on its axis to pick up debris. A camera can be located in or near the hose opening to be able to see where the debris is located and for confirmation that the debris is being removed and that the debris has fully been removed.
Attached to the inlet 12 is a tubular extension 26 that continues the inlet 12. At its lower end 28 the hose 30 is attached. Hose 30 extends through support 32 and hose guide 34. Hose guide 34 is a bend of a desired angle and shown as a 90 degree bend in
In use in
A combination camera and light shown schematically as 50 can be deployed in the hose 30 or adjacent to it on the outside. It can be powered and send images to the surface through a line or lines from the surface and a swivel connection or slack can be employed to avoid getting the lines in a bind. The line can be fiber optic for video and for lighting the subject area. The camera 50 will telescope with the hose 30 and a conduit or conduits for flushing fluid can be routed to the lens area to keep it clear of debris.
The assembly can be used to clean a recess 54 in a BOP stack 52 where debris 56 can accumulate with the rams in the open position. The entire assembly can be released with a release of the anchor assembly 36 and an entire BOP stack can be cleaned to assure future functionality. Other recesses in a tubular string can also be cleaned using the assembly and drawing in the debris 56 in to the directed end of the hose 30.
Other variations are contemplated such as the guide 34 being at angles different than 90 degrees or being a multi-component articulated assembly that can be controlled from the surface so that the guiding angle can be changed with the assembly in the subterranean location to better direct the end of the hose 30 so there are more degrees of freedom of movement to pinpoint the end at the debris and even physically move the debris around to dislodge it. Alternatively the hose 30 can instead or as well be extended and retracted to accomplish the dislodging mission.
Those skilled in the art will appreciate that instead of stirring up all the debris as with a jet system and hoping to capture it the use of a vacuum system to pick up debris allows the debris to be removed with minimal agitation so that the chance for getting more of it is heightened. Being able to see the process with a light and camera adds to its effectiveness and allows inspection to determine that the task is effectively completed. There are also multiple degrees of freedom of movement of the end of the hose with the anchor set. It can be extended and retracted in a given plane or rotated in that plane. The hose end can be skewed above or below a given plane with an articulated guide or its orientation can be kept in on plane as it is raised or lowered to an adjacent parallel plane. Combinations of such movements can be employed to reach hard to get to locations or to use the hose end as a pry to dislodge debris so that it can be collected by the hose.
The above description is illustrative of the preferred embodiment and various alternatives and is not intended to embody the broadest scope of the invention, which is determined from the claims appended below, and properly given their full scope literally and equivalently.
