Patent Publication Number: US-2022213761-A1

Title: Gauge cutter and sampler apparatus

Description:
TECHNICAL FIELD 
     The present disclosure relates to a wellbore tool for gauging a wellbore and sampling particles in the wellbore. 
     BACKGROUND 
     Gauge cutters are commonly used in petroleum industry for ensuring accessibility of tubing/casing/liner prior to running any other sub-surface tools inside the well. A gauge cutter is a tool with a round, open-ended bottom which is milled to an accurate size. Large openings above the bottom of the tool allow for fluid bypass while running in the hole. Often a gauge ring will be the first tool run on a slickline operation. A gauge cutter can also be used to remove light paraffin that may have built up in the casing and drift runs also. For sampling or removing the paraffin or any other mechanical debris, formation sand, scale sand bailer is used. 
     SUMMARY 
     In certain aspects, a wellbore gauge cutter apparatus includes a sampling body defining a central recess extending from an inlet at a first end of the sampling body to an outlet at a second end of the sampling body. The wellbore gauge cutter apparatus also includes a gauge cutter connected to the sampling body. The gauge cutter is configured to dislodge particles from an inner wall of a wellbore. The sampling body has an inner wall defining the central recess and a hollow cylindrical divider having a central aperture. The hollow cylindrical divider is arranged concentrically within the central recess of the sampling body. The sampling body also includes a first flow path defined in the central aperture of the hollow cylindrical divider, a second flow path defined between an outer wall of the hollow cylindrical divider and the inner wall of the sampling body, and a fluid permeable screen arranged in either a first flow path or the second flow path. The fluid permeable screen is configured to collect a portion the particles dislodged by the gauge cutter. 
     In some cases, the first flow path and the second flow path extend from the inlet to the outlet. 
     In some embodiments, a shape of the gauge cutter and the shape of the sampling body match. 
     In some apparatuses, the first and second flow path of the sampling body are merged between the inlet and an uphole end of the hollow cylindrical divider. 
     In some cases, the first flow path is larger than the second flow path, wherein the screen is arranged in the second flow path. 
     In some embodiments, the second flow path of the sampling body is larger than the first flow path of the sampling body. The fluid permeable screen may be arranged in the first flow path. 
     In some apparatuses, the outlet of the sampling body is fluidly connected with an inlet of the gauge cutter. 
     In some embodiments, the portion of the particles is 100 grams by weight. 
     Some fluid permeable screens are removable from the sampling body. 
     In certain aspects, a wellbore gauge cutter apparatus includes an uphole end, a downhole end, and a cylindrical body. The cylindrical body defines a central recess extending from a first end of the cylindrical body to a second end of the cylindrical body. The wellbore gauge cutter apparatus also includes a cutter blade connected to the second end of the cylindrical body and a sample collector permeable to fluids. The sample collector is configured to retain particles. The sample collector arranged in the central recess of the cylindrical body. The central recess of the cylindrical body has a first cross-section having a first area, wherein the sample collector has a second-cross section having a second area, wherein the second area is less than the first area. 
     In some cases, the cylindrical body includes a first beam extending from first end of the cylindrical body to a connector. The cylindrical body can include a second beam extending from first end of the cylindrical body to a connector. In some cases, the first beam and second beam define an inlet and the inlet is in fluid communication the central recess of the cylindrical body. 
     Some sample collectors have a volume of about 0.3 liters to about 1 liter. 
     The sampling collector can include a membrane permeable to fluids. In some cases, the sampling collector is releasable from the cylindrical body. Some sample collectors are annularly shaped. In some embodiments, the first cross-section is circular. The cutter blade can be a gauge cutter. 
     In certain aspects, a method includes cutting, by a gauge cutter during a downhole motion of a gauge cutter apparatus through a casing of a wellbore, a material from internal walls of the casing of the wellbore such that particles of the material are suspended in fluid. The method also includes, after cutting the material from the internal walls, separating, by sampling body mechanically connected to the gauge cutter during an uphole motion of the gauge cutter apparatus through the casing of the wellbore, the fluid with the suspended particles in the sampling body into a first flow path of the sampling body or a second flow path of the sampling body. A majority of the fluid entering the sampling body is separated into the first flow path of the sampling body. The method also includes collecting a sample of the particles with a sample collector arranged in the second flow path of the sampling body. 
     Some methods include removing the sample collector from the sampling body to access the collected particles. 
     In some cases, the method includes analyzing the particles using an x-ray diffraction test, an acid test, or both an x-ray diffraction test and an acid test. 
     In some embodiments, the first and second flow paths extend to an outlet of the gauge cutter apparatus. 
     The wellbore gauge cutting apparatus samples the debris and particles dislodged by the wellbore gauge cutter apparatus in a single trip. The wellbore gauge cutter apparatus may increase the speed of cutting and debris sampling and may reduce errors by eliminating the need to switch tools between runs. Further, the sampling body protects the collected sample during cutting and transportation to the surface so that the samples may be accurately analyzed. Analyzing the sample can also determine the chemical compositions and natures of the particle. A fit-for-purpose removal well intervention can be designed around the chemical composition. 
     The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of a gauge cutter apparatus with a removable sampling body. 
         FIG. 2  is a partial front cross-sectional view of the gauge cutter apparatus of  FIG. 1 . 
         FIG. 3  is a bottom view of an outlet of the wellbore gauge cutter apparatus of  FIG. 1 . 
         FIGS. 4A-4C  are front views of the wellbore gauge cutter apparatus of  FIG. 1  in operation. 
         FIG. 5  is a front view of the sampling body of the wellbore gauge cutter apparatus from a sample collector of the wellbore gauge cutter apparatus of  FIG. 1  during sample removal. 
         FIG. 6  is a flow diagram of an example of a method for using a gauge cutter apparatus. 
         FIG. 7  is a front view of a wellbore gauge cutter apparatus with an alternative embodiment of a gauge cutter, a first sample collector, and a second sample collector. 
         FIGS. 8A and 8B  are front views of the wellbore gauge cutter apparatus having the gauge cutter, first sample collector, and second sample collector, in operation 
         FIGS. 9A and 9B  are cross-sectional views of the second sample collector of the wellbore gauge cutter apparatus during sample removal. 
         FIG. 10  is a perspective view of a gauge cutter apparatus having a sampling body and a gauge cutter axially spaced from the sampling body. 
         FIG. 11  is a cross sectional front view of the gauge cutter apparatus of  FIG. 10 . 
         FIG. 12  is a front view of a sample collector with apertures of various sizes. 
     
    
    
     Like reference symbols in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
     The gauge cutter apparatus may be used in wellbores to dislodge, scrape, or clean debris from the inner walls of a wellbore casing, or other tubular structure in the wellbore. The apparatus includes a sampling body with sampling collectors or screens that are permeable to fluids. The sampling collectors retain a portion of the particles suspended in the fluid for later analysis at the surface. In use, the gauge cutter apparatus undergoes running-in-hole (RIH) operation to dislodge debris from an internal wall of the casing. The debris, in the form of particles, is suspended in a fluid in the casing. The wellbore gauge cutter apparatus then undergoes pulling out of hole (POOH) operation in which a portion of the fluid in the casing flows through the sample collector or screen. The other portion of the fluid with suspended particles in the casing flows through the gauge cutter apparatus but does not interact with the sampling collector or screen. At the surface, the sampling collector can be separated from the sampling body to access the collected sample for further analysis. 
     The wellbore gauge cutter apparatus samples the debris and particles dislodged by the wellbore gauge cutter apparatus in a single trip. The gauge cutter apparatus may increase the speed of cutting and debris sampling and may reduce errors by eliminating the need to switch tools between runs. Further, the sampling body protects the collected sample during cutting and transportation to the surface so that the samples may be accurately analyzed. In some instances, the sampling body holds the collected particles in order of dislodgment, so that the sample deepest in the sample collector can be inferred to have been collected farthest from the surface. In other instances the sample deepest the sample collected can be inferred to have been collected nearest to the surface. Knowing the axial position of collected particles relative to the axial position of other collected particles can be beneficial in determining the type and severity of the debris formed on the casing. Analyzing the sample can also determine the chemical compositions and natures of the particle. A fit-for-purpose removal well intervention can be designed around the chemical composition and, if applicable, the positions of the particles relative to the wellbore. 
       FIG. 1  is a perspective view of a wellbore gauge cutter apparatus  100  with a removable sampling body  102 . The sampling body (cylindrical body)  102  defines a central recess  104  that extends from an inlet  106  at the first end (uphole end)  108  of the sampling body  102  to an outlet  110  at a second end (down hole)  112  of the sampling body  102 . The inlet  106  and outlet  110  are open to the environment in which the wellbore gauge cutter apparatus  100  is located. The inlet  106  and outlet  110  are in fluid connection by the central recess  104 . The sampling body  102  further includes an inner wall  114  that defines the central recess  104 . The inner wall  114  is shown as cylindrical, however, the inner wall may have other shapes, for example frustoconical, square, rectangular, elliptical, or polygonal. 
     The wellbore gauge cutter apparatus  100  further includes a sample collector  116  (e.g., a screen) arranged at an axial position in the central recess  104  of the sampling body  102 . The sample collector  116  is arranged at the outlet  110  of the central recess  104 , however, other sample collectors may be arranged at the inlet of the sample body, or at any other location in the central recess between the inlet of the sampling body and the outlet of the sampling body. The sample collector  116  is permeable to fluids and is configured to retain particles, solids, and/or debris. The sample collector can be or include a screen, (fluid) divider, permeable partition, flexible membrane, rigid membrane, filter, fabric mesh, wire mesh, or a combination thereof. The sample collector can be entirely rigid, entirely flexible, or both rigid and flexible at different portions of the sample collector. In some instances, the sample collector is made of an elastic, stretchable material. The sample collector can be made of plastic, metal, fabric, polymer, elastomers, or combinations thereof. 
     The sample collector  116  is annularly shaped such that an opening  118  is defined in the center of the sample collector  116  and a base  120  connects or mounts the sample collector  116  to the inner wall  114 . The sample collector  116  includes prongs  122  separated by slots  124 , that extend from the base  120  and terminate at the opening  118 . The slots  124  are open spaces though which fluid, and particle of smaller than a predetermined size, may flow. The width of the slot is about 0.1 mm to about 15 mm (e.g., 0.5 mm to about 10 mm). The width of the slots may be adjusted to account for a larger or a smaller particle size. The prongs  122  retain particles larger than the width of the slots  124  when fluid containing particles flows through the sample collector  116 . The sample collector  116  retains particles larger than 1 mm, however, the sample collector can be formed to retain particle sized from at least 0.1 mm to 12 mm. The sample collector  116  can be disconnected from the inner wall  114  of the central recess  104 , and removed from the sampling body  102  via the outlet of the sampling body  102 , described further with reference to  FIG. 5 . 
     The wellbore gauge cutter apparatus  100  further includes a gauge cutter (cutting blade)  126  configured to dislodge debris from an internal wall of a wellbore. The gauge cutter extends (downhole) from on the second end  112  of the sampling body  102  so that a free end  128  of the gauge cutter, scrapes, cuts, or scours the inner wall of the wellbore. The gauge cutter  126  defines an aperture  129  that extends through the gauge cutter  126 . The aperture  129  and the outlet  110  are aligned such that the aperture  129  and outlet  110  are in fluid communication. In use, the dislodged debris is suspended in fluid in the form of debris particles. A portion of the particles can be collected by the sample collector  116 . Some gauge cutters are integrally formed with the sampling body or are connected to the sampling body (e.g., by mounting or releasable attachment). 
     The gauge cutter  126  is the same shape and size as the sampling body  102 , such that both are cylindrically shaped and have the same diameter. Some gauge cutters are shaped differently from the sampling body, in that the gauge cutter may have a larger diameter or may mirror the shape of the well bore casing to form a close fit with the casing. In some instances, the gauge cutter is detachable from the second end of the sampling body and replaceable by a different gauge cutter. The connection between the gauge cutter and the sampling body may be a snap fit connection, magnetic connection, bolted connection, tongue and groove connection, or any other mechanical connection known in the art. Such an embodiment is described in further detail with reference to  FIGS. 10 and 11 . 
     The wellbore gauge cutter apparatus  100  includes a connector  130  that connects the wellbore gauge cutter apparatus  100  to a slick line, wireline, or coiled tubing. A first beam  132  and a second beam  134  of the sampling body  102  arranged at the first end  108  of the sampling body  102  each extend to the connector  130 . The beams  132 ,  134  at least partially define the inlet  106  of the sampling body  102 . The inlet  106  formed by the beams  132 ,  134  is in fluid communication with aperture  129  of the gauge cutter  126  via the outlet  110  defined at the second end  112  of the sampling body  102  and the central recess  104 . 
       FIG. 2  is a partial cross-sectional view of the gauge cutter apparatus  100 . The central recess  104  of the sampling body  102  is exposed to view the central recess  104 . 
       FIG. 3  is a bottom view of the outlet  110  of sampling body  102  of the wellbore gauge cutter apparatus  100  as viewed through the aperture  129  of the gauge cutter  126 . The sample collector  116  has an outer diameter d sco  defined at the base  120  an inner diameter d sci  which defines the opening  118 , and a cross section having an area A sc . The cross sectional area A sc  of the sample collector  116  is generally annular, however, the cross section of the sample collector may be a different shape, for example, a circle, crescent, half circle, square, triangular, polygonal, or any other shape. 
     The sampling body  102  has an external diameter d bo  ( FIG. 4C ). The central recess  104  of the sampling body  102  also has a diameter d cr  ( FIG. 4C ) and a cross sectional area A cr . The cross sectional area A ca  of the central recess  104  is circular, but however, the cross section of other central recesses may be a different shape, for example, annular, crescent, half circle, square, triangular, polygonal, or any other shape. 
     The cross sectional areas A sc , A cr  of the sample collector  116  and the central recess  104  are taken at the same axial location in the central recess  104 . The cross sectional area A sc  of the sample collector  116  is less than the cross sectional area A cr  of the central recess  104  (e.g., less than half), because the sample collector  116  only extends into a part of the central recess  104 , not across the entire central recess  104 . The ratio of the cross sectional area A sc  of the sample collector  116  to the cross sectional area A cr  of the central recess  104  can be, for example, 1:8, 1:6, 1:4, 1:3, 1:2, 2:3, 3:4, 4:5, 5:6, 6:7, 7:8, 8:9, or 9:10. 
     This configuration forms two flow paths in the central recess  104 . A first flow path  136  ( FIG. 4B ) and a second flow path  138  ( FIG. 4B ). The first flow path  136  extends between the inlet  106  and the outlet  110  and does not interact with the sample collector  116 . The second flow path  138  extends between the inlet  106  and the outlet  110  via the sample collector  116  so that the particles and fluid flowing in the second flow path  138  are filtered by the sample collector  116 . 
       FIGS. 4A-4C  are front views of the wellbore gauge cutter apparatus  100  in operation.  FIG. 4A  shows the wellbore gauge cutter apparatus  100  during RIH operation. The wellbore gauge cutter apparatus  100  is moved downhole by the extension of a slickline  140 . The gauge cutter  126  cuts debris  142   a  from an internal wall  144  of a wellbore casing  146 . The cut or dislodged debris  142   a  forms particles  142   b  that are suspended in the fluid in the casing  146 . The fluid moves uphole relative to the wellbore gauge cutter apparatus  100  moving downhole. Particles  142   b  are not collected in the sample collector  116  as the wellbore gauge cutter apparatus  100  moves downhole. 
       FIG. 4B  is a front view of the wellbore gauge cutter apparatus  100  during POOH operation. The wellbore gauge cutter apparatus  100  is moved uphole by the retraction of the slickline  140 . The fluid and particles  142   b  in the casing move downhole relative to the wellbore gauge cutter apparatus  100  moving uphole. The fluid and particles  142   b  in the central recess  104  are divided into the first flow path  136  and the second flow path  138 . A first portion of the fluid and particles  142  flows through the first flow path  136 . A second portion of the fluid flows the second flow path  138 . The first and second portion of fluid, together, form the total fluid flow in the central recess  104 . In some instances, the first and second flow paths are merged from the inlet  106  to an uphole edge of the sample collector. 
     The fluid and particles  142   b  in the first flow path  136  enter the inlet  106 , bypass the sample collector  116 , and exit the outlet  110 . The fluid and particles  142   b  in the first flow path  136  do not interact with the sample collector  116 . The fluid and particles  142   b  in the second flow path  138  enter the inlet  106  and are separated by the sample collector  116 . Particles  142   b  of a minimum size are retained in the sample collector  116 . After separation (e.g., sampling, filtering), the fluid and particles  142  less than the minimum particle size of the sample collector  116  exit the outlet  110 . 
     In some instances first portion of the fluid is larger than the second portion of the fluid, so that the first flow path is larger than the second flow path. In some instances, the second portion of the fluid is larger than the first portion of the fluid, so that the second flow path is larger than the first flow path. Regardless, as the sample collector  116  holds more particles  142   b  less fluid can flow through the second flow path  138 . As a result, over time, the second portion of the fluid can decrease while the first portion of the fluid increases. In some cases, when the sample collector is full, the all fluid in the central recess flows through the first flow path. 
     The sample collector  116  retains a small portion of the total number or particles present in the fluid, for example a particle weight of at least 100 grams (e.g. 50 grams to 1000 grams). 
       FIG. 4C  shows a close view of the sample collector  116  in  FIG. 4B . The sample collector  116  retains particles  142   b  and has a volume of about 0.3 liters to about 1 liter (e.g., 0.5 liters to 0.75 liters). Some sample collectors have a volume between 0.1 liters and 1.5 liters, inclusive. The particles may include wax particles, formation fine particles, scale particles (e.g., CaCO3, NaCl, BaSO4, Sr2SO4, FeS), corrosion particles, metal particles, or a combination thereof. 
       FIG. 5  is a front view of the sampling body  102  of the wellbore gauge cutter apparatus  100  during sample removal. The sample collector  116  is removable or separable from the sampling body  102 . In the separated state, the collected sample of particles  142   b  are easily accessible for further testing in a lab. The order in which the particles  142   b  were collected may also preserved. In some instances, if the ordering of collection is known, a depth or position of the particles, or type of particle, can be determined. 
       FIG. 6  is a flow diagram of an example of a method  200  for using a gauge cutter apparatus. The method is described with reference to gauge cutter apparatus  100 , however, the method may be used with any application apparatus described herein or known in the art. 
     The method includes connecting the wellbore gauge cutter apparatus  100  to a slickline  140  and inserting the wellbore gauge cutter apparatus  100  into a wellbore casing  146  containing fluid and debris on the internal wall  144  of the casing  146 . Next, the method  200  includes moving the gauge cutter  126  during a downhole motion of the wellbore gauge cutter apparatus  100  through the casing  146  of the wellbore, thereby cutting debris  142   a  (material) from the internal walls  144  of the casing  146  of the wellbore. The particles  142   b  of the debris (material)  142   a  are suspended in fluid. (Step  202 ). The wellbore gauge cutter apparatus  100  continues cutting debris  142   a  from the internal walls  144  of the casing  146 . The downhole cutting motion eventually cuts the entire casing, or predetermined length of debris (material)  142   a  from the casing  146 . 
     After cutting the debris (material)  142   a  from the internal walls  144 , the wellbore gauge cutter apparatus  100  is moved uphole thereby sampling a portion of the particles  142   b  in the fluid. The method includes moving the gauge cutter apparatus  100  uphole, thereby separating, by the sampling collector  116  mechanically connected to the gauge cutter  126 , the fluid with the suspended particles  142   b  in the sampling body  102  of the wellbore gauge cutter apparatus  100  into a first flow path  136  of the sampling body  102  or a second flow path  138  of the sampling body  102 . In some cases, a majority of the fluid entering the sampling body  102  is separated into the first flow path  136  of the sampling body  102 . (Step  204 ). 
     Next, the wellbore gauge cutter apparatus  100  collects a sample of the particles  142   b  with the sampling collector  116  (screen or membrane) arranged in the second flow path  138  of the sampling body  102 . (Step  206 ). 
     The wellbore gauge cutter apparatus  100  continues to move uphole as the sampling collector  116  fills with particle  142   b . The sample collector  116  may fill to a maximum volume, at which time, no or small amounts of fluid can flow in the second flow path  138 . When the sample collector  116  is full, a majority (or all) of the fluid in the sampling body  102  flows through the first flow path  136 . 
     The wellbore gauge cutter apparatus  100  reaches the surface and may be taken to a lab or analysis station to analyze the particles  142   b  collected in the sample collector  116 . In these settings, the sampling body  102  is disconnected from the sample collector  116  and sample collector (e.g., a membrane) is removed from the sampling body to access the collected particles  142 . The method further includes analyzing the particles using X-ray Diffraction (XRD) and/or an acid test. 
       FIG. 7  is a front view of a wellbore gauge cutter apparatus  100  with an alternative embodiment of a gauge cutter  151 , a first sample collector  152 , and a second sample collector  154 . The sample collector  152  is substantially similar to the sample collector  116 , however, the sample collector  152  is a hollow cylindrical divider (body)  152   a  having slots  152   b  and a central aperture  152   c . The sample collector  152  is arranged concentrically within the sampling body  102  and extends from the outlet  110  to the inlet  106  so that the fluid entering the sampling body  102  is divided between first and second flow paths  156 ,  158  upon entering the sampling body  102 . 
     The first flow path  156  is defined in the central aperture  152   c  of the sample collector  152 . The second flow path  158  is defined between the inner wall  114  of the sampling body  102  and an outer wall of the cylindrical divider  152   a . The first and second flow paths  156 ,  158  extend from the inlet  106  to the outlet  110  of the sampling body  102 . 
     The gauge cutter  151  of the wellbore gauge cutter apparatus  100  is substantially similar to gauge cutter  126 , however, the gauge cutter  151  includes a sample inlet  154   a  that extends to a second sample collector  154  arranged in gauge cutter  151 . In this configuration, the wellbore gauge cutter apparatus  100  collects samples when performing RIH and POOH operations (moving downhole and uphole). The gauge cutter  151  also includes a sample outlet  154   b . During operation the sample outlet  154   b  is covered by the sampling body  102 . In some cases, the sample outlet is exposed during operation. 
       FIGS. 8A and 8B  are front views of the wellbore gauge cutter apparatus  100  having the gauge cutter  151 , first sample collector  152 , and second sample collector  154  in operation.  FIG. 8A  is a cross section front view of the wellbore gauge cutter apparatus  100  cutting the debris  142   a  from the casing  146 . The wellbore gauge cutter apparatus  100  moves downhole (RIH operation) to cut the debris  142   a  from the internal wall  144  of the casing  146 . A portion of the debris  142   a  is directed into the sample inlet  154   a  arranged on the free end  128  of the gauge cutter  151 . The debris  142   a  enters the sample inlet  154   a  and is held in the second sample collector  154 . Further movement downhole, moves the collected debris  142   a  in the sample collector  154  towards the covered sample outlet  154   b  of the sample collector  154 . Some of the dislodged debris  142   a  forms particles  142   b  in the fluid. 
     In  FIG. 8B , the wellbore gauge cutter apparatus  100  moves uphole (POOH operation) and begins to collect samples of the particles  142   b  in the fluid. The fluid and particles  142   b  are divided into the first flow path  156  and the second flow path  158 . The fluid and particles  142   b  diverted into the second flow path  158  are separated by the sample collector  152  and a portion of the particles  143   b  are retained in the sample collector  152 . The fluid and small particles  142   b  that passed through the sample collector  152  exit the sampling body  102  via the outlet  110 . The fluid and particles  142   b  that enter the first flow path  156  at the inlet  106  do not interact with the sample collector  152  and exit the outlet  110 , unfiltered. A small sample of particles  142   b  and debris  142   a  is collected using the first sample collector  152  and second sample collector  154 . 
       FIGS. 9A and 9B  are cross-sectional views of the second sample collector  154  of the wellbore gauge cutter apparatus  100  during sample removal. The first and second sample collectors  152 ,  154  are separable from the sample body  102 . Separating the sample collectors  152 ,  154  from the sample body  102  exposes the sample outlet  154   b  of the second sample collector. To extract the sample of debris  142   a , a pipe can be inserted into the sample outlet  154   b  and can press on the collected debris  142   a  to move the debris  142   a  through the sample inlet  154   a . The collected debris samples from the first and second sample collectors  152 ,  154  can then be analyzed using techniques known in the art. 
       FIG. 10  is a perspective view of a wellbore gauge cutter apparatus  100  having a removable sampling body  102  and a gauge cutter  160 . The gauge cutter  160  is substantially similar to the gauge cutter  126 , however, the gauge cutter  160  has a gauge body  162 , a blade  164 , and a gauge connector  166  that connects to the sampling body  102  to the gauge cutter  160 . The gauge connector  166  connects to a protrusion  168  of the sampling body  102  extending from the second end  112  of the sampling body  102 . The gauge connector  166  and protrusion  168  have a snap fit connection, however, the gauge connector and protrusion may be connected by any suitable connection. The gauge cutter  160  is spaced axially from the sampling body  102  by the gauge connector  166  and protrusion  168 . The aperture  129  that extends through the gauge cutter  160  has a gauge inlet  170  and a gauge outlet  172  that are open to the environment. 
       FIG. 11  is a cross-sectional view of the wellbore gauge cutter apparatus  100  having the gauge cutter  160  axially spaced from the sampling body  102 . The sampling body  102  and sampling collector  154  are connected such that fluid flows into the inlet  106  of the sampling body  102  and exits the outlet  110  of the sampling body  102  via either the first flow path  156  or second flow path  158  during POOH operation. The fluid containing particles  142   b  then enters the gauge inlet  170  and exits the gauge outlet  172  via the aperture  129  of the gauge cutter  160 . The gauge cutter  160  has an outer diameter d gc  ( FIG. 3 ), which is sized such that the gauge cutter  160  cuts debris  142   a  from an internal wall  144  of a wellbore casing  146 . The diameter d gc  ( FIG. 3 ) of the gauge cutter  160  and the outer diameter d bo  of the sample body  102  ( FIG. 4C ) are equal, however, in some cases, the diameter of the gauge cutter is larger than the outer diameter of the sample body. In some instances, the gauge cutter  160  can be disconnected from the sampling body  102  and replaced with a new gauge cutter  160 . In some instances, the gauge cutter is replaced due to wear. In some instances the gauge cutter is replaced with a gauge cutter of equal or greater diameter. In some instances, the gauge cutter is replaced with a gauge cutter of a different shape. 
       FIG. 12  is a front view of a sample collector  180  having apertures  182  of various sizes. The sample collector  180  is substantially similar to the sample collector  152 , however, the sample collector  180  includes three types of apertures  182 . The apertures  182  include first apertures  184  having a first width, second apertures  186  having a second width, and third apertures  188  having a third width. The width of the third apertures  188  is equal to the width of the second apertures  186 . The width of the first apertures  184  is larger than the widths of the first and second apertures  186 ,  188 . 
     The sample collector  180  has a first (uphole) portion  190 , a second portion  192 , and a third (downhole) portion  194 . The second portion  192  extends between the first portion  190  and the third portion  194 . The first apertures  184  are arranged in the first portion  190 . The second apertures  186  are arranged in the second portion  192 . The third apertures  188  are arranged in the third portion  194 . In this configuration, the second and third portions  192 ,  194  of the sample collector  180  hold smaller particles than the third portion  194  of the sample collector  180 , thereby forming a gradient filter. The sample collector  180  with a gradient filter is able to retain a range of particle sizes, e.g., large particles and small particles. As the sample collector  180  fills with particles, the minimum particle size changes. Therefore, small and large particles may initially be sampled, however, as the volume of particles in the sample collector  180  increases, only large particles are retained and smaller particles may flow through sample collector  180 . 
     In the sample collector  180 , the first apertures  184  are slots, the second apertures are circular holes, and the third apertures are circular holes, however, in other sample collectors the first, second, and third apertures may be shaped differently. In some sample collectors, the first, second, and third apertures are the same shape. In some sample collectors, the first, second, and third apertures are each different shapes. 
     In use, fluid and particles flow through the first flow path in a central aperture  198  of the sample collector  180  or flow through a second flow path. The fluid and particle flowing in the second flow path interacts with the sample collector  180 . First, the third portion  194  of the sample collector  180  filters the fluid and particles, retaining only particles that are larger than the width of the third apertures  188 . As more particles are gathered, the third portion  194  of the sample collector  180  fills. The fluid and particles then flow through the second apertures  186 , so that the sample collector retains only particles larger than the width of the second apertures  186 . As more particles are gathered, the second portion  192  of the sample collector  180  fills. The widths of the second and third apertures  186 ,  188  are equal, therefore, the minimum retained particle size of the second and third portions  192 ,  194  are the same. 
     Once the second portion  192  is filled, the fluid and particles then flow through the first apertures  184 , so that the sample collector retains only particles larger than the width of the first apertures  184 . The width of the first apertures  188  is larger than the second and third apertures  186 ,  188 , therefore, the minimum retained particle size in the first portion is larger than the minimum retained particle size of the second and third portions  192 ,  194 . 
     The gauge cutter apparatus is removed, the sample collector  180  is retrieved and the collected particles are examined. 
     While the sample collector  180  has been described as having apertures that decrease in width from the first portion of the sample collector to the third portion of the sample collector, the apertures may also increase in width the first portion of the sample collector to the third portion of the sample collector. Some sample collectors include two portions. Some sample collectors include more than three portions, for example, 4, 5, or 6 portions, each with apertures of a specified width. 
     In some sample collectors, the first, second, and third portions are made of different material, for example, the third portion may be a rigid membrane, the second portion may be a flexible fabric, and the first portion may be a polymer membrane. In some embodiments, the first, second, and third portions are releasably attached to each other, so that the sample collector may be altered to fit different wellbores or particle types. 
     A number of embodiments have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other embodiments are within the scope of the following claims.