Combination debris collection and visual validation assembly

Abstract

A method and apparatus for efficient and effective collection of debris from a wellbore, while permitting simultaneous visual verification of such debris collection. A debris collection assembly comprises a combination of one or more of the following: a reverse circulation assembly, a video assembly and at least one filter assembly. Fluids are circulated into a wellbore annular space via the reverse circulation assembly, into the video assembly where fluid and any associated debris are visually sensed and recorded, into the filter assembly where debris is separated from the fluids and collected, before cleaned fluids are circulated out of the wellbore. The components of the debris collection assembly are substantially modular, and can be run in combination with conventional wellbore cleaning tools (such as, for example, workstring-conveyed brushes, scrapers and/or magnets).

What is claimed: 
     
         1 . A method for visually-monitored downhole removal of solid debris from well fluid in a wellbore, the method comprising the steps of:
 (a) inserting a debris collection assembly into a tubular workstring deployed in a wellbore, the debris collection assembly comprising a reverse circulation sub-assembly (RCSA), a video sub-assembly (VSA), and a filter sub-assembly (FSA), the RCSA in internal flow bore communication with a surface supply of clean well fluid delivered to the RCSA via an internal flow passageway through the workstring;   (b) positioning the debris collection assembly at a pre-determined wellbore location such that the debris collection assembly is adjacent debris in local well fluid in an annular space separating the debris collection assembly from the wellbore;   (c) sealing the annular space so as to create a predetermined well fluid flow pathway from the internal flow bore of the RCSA into the annular space, then through the VSA and the FSA, then back into the annular space and up to the surface;   (d) passing clean well fluid from the internal flow bore of the RCSA, through the RCSA, and into the annular space;   (e) diverting, via well fluid flow, debris in the annular space into an internal VSA pathway in the VSA;   (f) acquiring, as the debris passes through the internal VSA pathway; visual data regarding the debris with a video camera assembly mounted inside the VSA;   (g) processing the visual data;   (h) diverting, again via well fluid flow, the debris out of the internal VSA pathway and into an internal FSA pathway in the FSA; and   (i) collecting the debris in the FSA as it passes through the internal FSA pathway.   
     
     
         2 . The method of  claim 1 , in which step (c) includes the substeps of:
 (c1) providing a radially-extendable annular brush ring on the RCSA;   (c2) extending the brush ring so as to seal the annular space, and   (c3) selectively cleaning an internal surface of the wellbore with the brush ring.   
     
     
         3 . The method of  claim 1  or  2 , in which the visual data includes data selected from the group consisting of (1) still pictures, and (2) motion video, and in which step (g) includes the substeps of:
 (g1) storing the visual data in local memory included in the video camera assembly; and 
 (g2) telemetering first selected portions of the visual data to the surface. 
 
     
     
         4 . The method of  claim 3 , in which substep (g2) further includes the substeps of:
 (g2.1) sending second selected portions of the visual data to the surface in real time; and   (g2.2) extracting third selected portions of the visual data from local memory and sending the third selected portions to the surface.   
     
     
         5 . The method of any of  claims 1 - 4 , in which step (i) includes the substep of:
 (i1) passing the debris through screens and slots.   
     
     
         6 . The method of any of  claims 1 - 5 , in which step (i) includes the substep of:
 (i2) passing the debris over magnets.   
     
     
         7 . The method of any of  claims 1 - 6 , in which the FSA comprises a plurality of individual filtration units in fluid flow series, and in which each filtration unit in the series is configured to collect successively smaller debris. 
     
     
         8 . The method of  claim 7 , in which step (i) includes the substep of:
 (i3) responsive to individual filtration units becoming clogged with debris, bypassing said clogged filtration units.