Abstract:
The present disclosure relates to a method and apparatus for sampling a fluid from an environment having a primary filtering on a focused sampling probe and guard filtering system that is exposed upon movement of the focused sampling probe.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/917,973, filed Dec. 19, 2013, the entire disclosure of which is hereby incorporated herein by reference. 
     
    
     BACKGROUND OF THE DISCLOSURE 
       [0002]    Sampling of formation fluids is an important aspect of the oil and gas exploration industry. Sampling occurs on either a wireline or “while drilling” to allow engineers and drillers the ability to identify subsurface conditions. 
         [0003]    As drilling of wellbores becomes more complex and directional drilling becomes more prevalent, ascertaining the position of petroleum bearing strata is important as the costs of drilling such wells increases. 
         [0004]    Conventional sampling apparatuses, however, have significant drawbacks and present challenges for drillers and engineers. Sampling systems can become clogged with materials during the drilling process. Some geological conditions have a tendency to clog sampling systems to the degree that sampling is difficult. 
         [0005]    Sampling systems can also be prone to other problems from mud or foreign particle intrusion. Probe systems, for example, may have articulated members that extend from a central body. The articulated members are used to help in formation sampling. The articulated members, however, are prone to fouling from downhole contaminants, thereby limiting the use of such members. 
       SUMMARY 
       [0006]    The aspects described in this summary are to be considered but one possible example embodiment. As a consequence, the aspects described in the summary should not be considered limiting. A tool, having a probe with probe barrel movable from a retracted position to an extended position, the probe having an inner packer configured to seal against a first surface, the inner packer movable from the retracted position to the extended position and the probe further configured with a primary filter positioned in the probe, a primary filter piston configured to move the probe from the retracted position to the extended position, a primary flow line configured to transport a sample fluid from the primary filter to an interior of the tool, a guard filter configured to accept a fluid from an environment and filter the fluid, the guard filter configured around the probe when the probe is in the retracted position, a guard filter piston, wherein at least a portion of the guard filter piston is positioned within an inner diameter of the guard filter, the guard filter piston configured to move the guard filter relative to the probe and expose the guard filter to the environment, an outer packer configured around the guard filter, the outer packer configured to seal against a second surface and a secondary flowline located between the inner packer and the outer packer, wherein the secondary flowline accepts the fluid from the guard filter. 
         [0007]    In another example embodiment, a method is disclosed having lowering a tool with a probe module into the wellbore, positioning the tool with the probe module against a formation, opening a flowline to the wellbore from an equalization valve, activating at least one pump such that fluid flow is accepted into a secondary flowline through a guard opening until a fluid sampled is clean enough to take a sample, accepting a fluid flow from a primary flowline when the fluid is clean, and capturing the fluid flow in a sample chamber. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The present disclosure is understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. 
           [0009]      FIG. 1  is a cross-sectional view of a guard filtering system for a probe system wherein the probe system is retracted, according to aspects of the present disclosure; 
           [0010]      FIG. 2  is a cross-sectional view of a guard filtering system for a probe system wherein the probe barrel is extended, according to aspects of the present disclosure; 
           [0011]      FIG. 3  is a cross-sectional view of a guard filtering system for a probe system wherein the probe barrel is extended out and both filter pistons are withdrawn, exposing primary and secondary filtering areas, according to aspects of the present disclosure; and 
           [0012]      FIG. 4  is a cross-sectional view of a guard filtering system for a probe system wherein the probe barrel and guard filter piston reside in different hydraulic ports, according to aspects of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact. 
         [0014]    The present disclosure relates to systems and methods for a downhole tool, such as a downhole tool that include a probe assembly. A downhole tool may be one of various tools deployed into a wellbore by means such as a drill string, wireline, and coiled tubing for performing downhole operations related to the evaluation, production, and/or management of one or more subsurface formations of interest. The probe assembly may include one or more probes that are extended from the downhole tool to isolate a region of the wellbore wall, and thereby establish fluid communication with the formation surrounding the wellbore. Fluid may then be drawn into the downhole tool using the probe. A typical probe employs a body that is extendable from the downhole tool and carries a packer at an outer end thereof for positioning against a sidewall of the wellbore. Such packers may include a relatively large element that can be deformed easily to contact the uneven wellbore wall (in the case of open hole evaluation), yet retain strength and sufficient integrity to withstand the anticipated differential pressures. These packers may be set in open holes or cased holes. They may be run into the wellbore on various downhole tools. While aspects of the disclosure are described in relation to a wireline tool, the same concepts can be applied to a “while drilling” tool. The aspects described herein, therefore, are not to be considered limiting. In addition, certain embodiments of the tool may include pumpout capabilities such that one or more pumps are used to obtain samples of formation fluid and move the formation fluid throughout the tool. In addition, embodiments of the tool may include various pressure measurement and sampling capabilities. 
         [0015]    Referring generally to  FIG. 1 , a cross-sectional view of an embodiment of a focused probe module  10  is illustrated as deployed in a wellbore. The focused probe module  10  may be one component of a downhole tool. The focused probe module  10  may have an axial axis or direction  12 , a radial axis or direction  14 , and a circumferential axis or direction  16 . Thus,  FIG. 1  shows an axial  12  cross-sectional view of the focused probe module  10 . The term focused may be used to refer to a probe module that includes one or more features that enable the focused probe module  10  to obtain cleaner (e.g., with fewer contaminants) formation fluid than a probe module without such features. The focused probe module  10  includes a plurality of components that are generally arranged concentrically about one another. In certain embodiments, one or more of the components of the focused probe module  10  may have a radial cross-sectional shape that is circular, oval, square, rectangular, or any other suitable shape for focused sampling. The following description will begin with the components disposed near the axial axis  12  of the focused probe module  10  and then move radially  14  outward from there. As will be described with respect to  FIGS. 1-3 , the focused probe module  10  is configured to move through several different configurations in the course of formation fluid sampling and the phase shown in  FIG. 1  may be described as a retracted configuration. 
         [0016]    The focused probe module  10  may include a primary filter piston  18  that may be used to control the flow of formation fluid into a primary portion  20  of the focused probe module  10 , as described in more detail below. The primary filter piston  18  may include a primary filter piston actuator  22  that may be used to move the primary filter piston  18  up or down in the axial direction  12 . The terms up and down are used in the following discussion for convenience with respect to  FIGS. 1-3 , but the focused probe module  10  may actually be disposed at a variety of different angles within the wellbore. The primary filter piston actuator  22  may use various techniques for moving the primary filter piston  18 , such as, but not limited to, hydraulics, mechanical techniques, electrical techniques, motors, or any combination thereof. The primary filter piston  18  may include a primary flowline  24  for conveying clean (e.g., substantially free of contaminants) formation fluid to another portion of the downhole tool for storage or analysis. In certain embodiments, the primary flowline  24  may extend through an interior of the primary filter piston  18  and/or primary filter piston actuator  22 . For example, the primary flowline  24  may extend through the center of the primary filter piston  18  and/or primary filter piston actuator  22 . The primary flowline  24  may include one or more openings  26  to enable the formation fluid to enter the primary flowline  24 . 
         [0017]    A primary filter  28  may be disposed concentrically surrounding at least a portion of the primary filter piston  18 . The primary filter  28  may include one or more primary filter openings or slots  30  to block particles and other debris from entering the primary flowline  24 , as described in more detail below. In other words, the primary filter  28  may be used to prevent clogging or blockage of the primary flowline  24 . The sizes of the primary filter openings or slots  30  may be selected to substantially block the passage of particles and other debris through the primary filter openings or slots  30  and yet allow the passage of formation fluid. In certain embodiments, the primary filter  28  may have a generally cylindrical shape with an interior surface of the primary filter  28  abutting the primary filter piston  18  to substantially block the flow of formation fluid in the axial direction  12  toward the primary filter piston actuator  22 . The primary filter  28  may also be removable so that the filter  28  may be replaced when clogged or when a different size or configuration of filter is desired. In certain embodiments, a portion (e.g., a primary filter  28  debris scraping portion) of the primary filter piston  18  may removable via a threaded connection to enable the portion to be replaced when it is worn or damaged without replacing the entire primary filter piston  18 . A probe barrel  32  may be disposed concentrically surrounding at least a portion of the primary filter  28  and the primary filter piston  18 . In certain embodiments, the probe barrel  32  may have a generally cylindrical shape. The probe barrel  32  may be used to move the primary portion  20  up or down in the axial direction  12 , as described in detail below. Thus, the probe barrel  32  may be coupled to the primary filter  28  and/or the primary filter piston  18 . In certain embodiments, the probe barrel  32  may include a primary flowline channel  34  to enable formation fluid flowing through the primary filter  28  to enter the primary flowline  24 , as described in detail below. 
         [0018]    An inner packer  36  may be disposed concentrically surrounding at least a portion of the primary filter  28 . The inner packer  36  may be made from a flexible material, such as, but not limited to, rubber, plastic, elastomers, or any combination thereof, to help provide a seal against the formation. In certain embodiments, the inner packer  36  may generally extend axially  12  beyond the primary filter  28  and primary filter piston  18  in a direction toward the formation. Thus, when the focused probe module  10  is extended toward the formation, the inner packer  36  contacts the formation, thereby establishing a seal against the formation. The primary portion  20  may include the primary filter piston  18 , primary filter piston actuator  22 , primary filter  28 , probe barrel  32 , and inner packer  36 . 
         [0019]    As shown in  FIG. 1 , a guard portion  38  may concentrically surround the primary portion  20 . Specifically, a guard filter piston  40  may be disposed concentrically surrounding at least a portion of the probe barrel  32 . In certain embodiments, the guard filter piston  40  may be abutting the probe barrel  32  and may have a generally cylindrical shape. A guard filter  42  may be disposed concentrically surrounding at least a portion of the guard filter piston  40 . The guard filter  42  may include one or more guard filter openings or slots  44  to block particles and other debris from entering a secondary flowline  46 , as described in more detail below. In other words, the guard filter  28  may be used to prevent clogging or blockage of the secondary flowline  46 . The sizes of the guard filter openings or slots  44  may be selected to substantially block the passage of particles and other debris through the guard filter openings or slots  44  and yet allow the passage of formation fluid. In certain embodiments, the guard filter  42  may have a generally cylindrical shape with an interior surface of the guard filter  42  abutting the guard filter piston  40  to substantially block the flow of formation fluid in the axial direction  12  toward the primary filter piston actuator  22 . The guard filter  42  may also be removable so that the filter  42  may be replaced when clogged or when a different size or configuration of filter is desired. In certain embodiments, the guard filter piston  40  may include a debris scraper  43  that may be used to scrape particles and debris from the inner surface of the guard filter  42  as the guard filter piston moves axially  12 . In certain embodiments, the debris scraper  43  may be made from a harder or more durable material than the guard filter piston  40 . Further, the debris scraper  43  may be coupled to the guard filter piston  40  via a threaded connection to enable the debris scraper  43  to be replaced when it is worn or damaged. 
         [0020]    An outer packer  48  may be disposed concentrically surrounding at least a portion of the guard filter  42 . Thus, the secondary flowline  46  may be disposed between the inner and outer packers  36  and  48 . The outer packer  48  may be made from a flexible material, such as, but not limited to, rubber, plastic, elastomers, or any combination thereof, to help provide a seal against the formation. In certain embodiments, the outer packer  48  may generally extend axially  12  beyond the guard filter  42  and guard filter piston  40  in a direction toward the formation. Thus, when the focused probe module  10  is extended toward the formation, the outer packer  48  contacts the formation, thereby establishing a seal against the formation. The guard portion  38  may include the guard filter piston  40 , guard filter  42 , and outer packer  48 . The primary portion  20  and guard portion  38  may be used together to provide focused sampling of the formation fluid. In other words, the inner packer  36  of the primary portion  20  provides a smaller, inner sealed portion separate from a larger, concentrically surrounding sealed portion provided by the outer packer  48  of the guard portion  38 . Thus, the primary portion  20  is more likely to provide sampling of clean formation fluid compared to the formation fluid obtained in the guard portion  38 . One or more components of the focused probe module  10  may be supported by or coupled to a probe shoe  50 . 
         [0021]      FIG. 2  is an axial  12  cross-sectional view of an embodiment of the focused probe module  10  in an extended configuration with the probe barrel  32  extended. As shown in  FIG. 2 , the probe barrel  32  has moved in the axial  12  direction away from the primary filter piston actuator  22  and toward the formation. Specifically, hydraulics, mechanics, or electronics may be used to move the probe barrel  32 . Accordingly, the inner packer  36 , primary filter piston  18 , and primary filter  28  are also moved toward the formation until the inner packer  36  contacts the wellbore wall, thereby establishing a seal with the wellbore wall. As the positions of the primary filter piston  18  and primary filter  28  have not changed, the primary filter piston  18  continues to substantially block the flow of formation fluid into the focused probe module  10 . The other components of the focused probe module  10  remain in substantially the same positions as shown in  FIG. 1 . Specifically, the guard filter piston  40  and guard filter  42  does not move with the probe barrel  32 . 
         [0022]      FIG. 3  is an axial  12  cross-sectional view of an embodiment of the focused probe module  10  in a sampling configuration with both the primary filter piston  18  and guard filter piston  40  retracted. As shown in  FIG. 3 , both the primary filter piston  18  and guard filter piston  40  have moved in the axial  12  direction toward the primary filter piston actuator  22  and away from the formation. Specifically, the primary filter piston actuator  22  has moved the primary filter piston  18  axially  12  toward itself and hydraulics, mechanics, or electronics may be used to move the guard filter piston  40 . Thus, in certain embodiments, the movement of the primary portion  20  may be independent from the movement of the guard portion  38 . Accordingly, clean formation fluid moves into the primary filter  28 , passes through the primary filter openings or slots  30 , enters the openings  26 , and flows through the primary flowline  24 . As described above, the primary filter  28  blocks particles and other debris from entering the primary flowline  24 . In addition, contaminated formation fluid moves into the guard filter  42 , passes through the guard filter openings or slots  44 , and flows through the secondary flowline  46 . As described above, the guard filter  28  blocks particles and other debris from entering the secondary flowline  24 . In certain embodiments, the clean formation fluid in the primary flowline  24  may be segregated from the contaminated formation fluid within the downhole tool. For example, contaminated fluid may be stored inside sections of the tool or may be ejected to the wellbore. The other components of the focused probe module  10  remain in substantially the same positions as shown in  FIGS. 1 and 2 . After sampling is complete, the focused probe module  10  may return to the extended configuration of  FIG. 2  and then to the retracted configuration of  FIG. 1  before the downhole tool is moved to another sampling location. Thus, the axial  12  movement of the primary filter piston  18  and the guard filter piston  40  help to remove or scrape off any debris or particles from the surfaces of the primary filter  28  and guard filter  42 , respectively, after each setting of the focused probe module  10 . In addition, there is no accumulation of debris or particles within the primary or secondary flowlines  24  and  46  because of the primary filter  28  and guard filter  42 , respectively. 
         [0023]      FIG. 4  is an axial cross-sectional view of another embodiment of the focused probe module  10 . Elements in common with those shown in  FIGS. 1-3  are labeled with the same reference numerals. The focused probe module shown in  FIG. 4  is in the retracted configuration, but may also be positioned in the extended configuration similar to that shown in  FIG. 2  and the sampling configuration shown in  FIG. 3 . As shown in  FIG. 4 , the probe barrel  32  and guard filter piston  40  reside in different hydraulic ports. Such a configuration may provide for additional control of the moving sequence (e.g., from the retracted configuration to the extended configuration to the sampling configuration and vice versa) for the probe barrel  32  and the guard filter piston  40  than if the probe barrel  32  and guard filter piston resided in the same hydraulic port. In other respects, the focused probe module  10  is similar to that shown in  FIGS. 1-3 . 
         [0024]    In certain embodiments, the process for using the focused probe module  10  with the downhole tool may include the following steps. In a first step, the tool including the focused probe module  10  is lowered into the wellbore. The focused sample module  10  is in the retracted configuration of  FIG. 1 . In a second step, hydrostatic pressure may be automatically applied to a backside of a compensating piston, which may increase the pressure of the hydraulic system. In a third step, the primary and/or secondary flowlines  24  and  46  are opened to the borehole from equalization valves in the focused probe module  10  or a packer module of the downhole tool. In a fourth step, the tool is set in place for testing and back up pistons and the probe are extended. In other words, the focused probe module  10  moves into the extended configuration of  FIG. 2  and then into the sampling configuration of  FIG. 3 . In a fifth step, formation fluid flows in the primary and secondary flowlines  24  and  46  and pretesting of the clean formation fluid in the primary flowline  24  is activated. In a sixth step, a decision is made whether to take a sample based on the pretest data. The decision may be made based on optical spectrometry or other measurement systems that allow for identification of contamination levels in the formation fluid flowing through the primary flowline  24 . In a seventh step, if sampling is desired, pumps of the downhole tool are activated to draw in formation fluid until the fluid is clean enough to take a sample. In an eighth step, valves are closed when sample chambers are full and the probe and pistons are retracted (e.g., the focused probe module  10  returns to the retracted configuration of  FIG. 1 ). The sample chambers may be determined to be full by monitoring pressures of the primary and/or secondary flowlines  24  and  46 . In a ninth step, tests may be repeated at the same or different locations of the wellbore. 
         [0025]    The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure.