Patent Publication Number: US-8967242-B2

Title: Auxiliary flow line filter for sampling probe

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/426,613, entitled “Auxiliary Flow Line Filter for Focused Sampling Probe,” filed Dec. 23, 2010, the entire disclosure of which is hereby incorporated herein by reference. 
    
    
     BACKGROUND OF THE DISCLOSURE 
     Wellbores (also known as boreholes) are drilled to penetrate subterranean formations for hydrocarbon prospecting and production. During drilling operations, evaluations may be performed of the subterranean formation for various purposes, such as to locate hydrocarbon-producing formations and manage the production of hydrocarbons from these formations. To conduct formation evaluations, the drill string may include one or more drilling tools that test and/or sample the surrounding formation, or the drill string may be removed from the wellbore, and a wireline tool may be deployed into the wellbore to test and/or sample the formation. 
     Formation evaluation may involve drawing fluid from the formation into a downhole tool for testing in situ and/or sampling. Various devices, such as probes and/or packers, may be extended from the downhole tool to isolate a region of the wellbore wall, and thereby establish fluid communication with the subterranean formation surrounding the wellbore. Fluid may then be drawn into the downhole tool using the probe and/or packer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure is best 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. 
         FIG. 1  is a sectional view of a probe block with a filter arrangement according to one or more aspects of the present disclosure. 
         FIG. 2  is a schematic side view of a probe block in transparency according to one conventional design. 
         FIG. 3  is a sectional view of a portion of an auxiliary filter according to one conventional design. 
         FIG. 4  is a schematic sectional view of a probe block according to one or more aspects of the present disclosure, the probe block depicted in a retracted or closed position. 
         FIG. 5  is a schematic sectional view of the probe block of  FIG. 4  in an extended or opened position. 
         FIG. 6  is a schematic perspective view, partially in transparency, of a portion of a probe block according to one or more aspects of the present disclosure. 
         FIG. 7  is a schematic perspective view, partially in transparency and partially in cross section, of the portion of the probe block shown in  FIG. 6 . 
         FIG. 8  is a sectional view of a portion of a probe block according to one or more aspects of the present invention, depicting a filter piston before it is retracted into the probe block. 
         FIG. 9  is a sectional view of the portion of the probe block shown in  FIG. 8 , depicting the filter piston retracted into the probe block. 
         FIG. 10  is a perspective view, partially in transparency, of a portion of a probe block with a sequence valve disposed at the bottom according to one or more aspects of the present disclosure. 
         FIG. 11  is a schematic view, partially in cross-section, of a drill string extending from a drilling rig into a wellbore penetrating a subterranean formation, the drill string including a probe module according to one or more aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     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. 
     Conventional probe module designs filter auxiliary flow through two filters attached to a probe block. Auxiliary fluid flow coming from a geotechnical formation, for example, between the inner and outer packers proceeds into a conventional probe module via holes in the probe block. These holes lead to the two filters attached to the probe block. In such conventional designs, the holes are prone to plugging. Further, the filters are static, that is, no mechanism is provided to clean the filters downhole. Therefore, once plugged, these static filters can only be cleaned after the tool is brought out of the wellbore and back to the surface. Still further, in order to service the sequence valve in a conventional probe module, the probe block has to be dismounted from the probe module, as well as the cover (face seal) used to secure the filters in the probe block. 
       FIG. 2  is a schematic side view of a conventional probe block  200  in transparency. The probe block  200  has an inner sealing packer  210  and an outer sealing packer  220  defining a central inlet  215  and a peripheral inlet  225 . The central inlet  215  and peripheral inlet  225  are coupled to two pumps (not shown) via a main flow line (not shown), and an auxiliary flow line  230 , respectively. The auxiliary flow line  230  includes three holes  232 ,  234 ,  236  shown vertically that connect to a fourth hole  238  shown horizontally. The fourth hole  238  leads into two static filters  240 ,  250 . In use, fluid may be drawn from the formation through the peripheral inlet  225  between the two sealing packers  210 ,  220  at the top, and may proceed down the three vertical holes  232 ,  234 ,  236  of the auxiliary flow line  230 , through the horizontal hole  238  of the auxiliary flow line  230 , and into the static filters  240 ,  250  attached in the probe block  200  of the downhole tool. 
     Still referring to  FIG. 2 , four bolts  262 ,  264 ,  266 ,  268  that are used to secure the face seal (not shown) are also provided to secure the filters  240 ,  250 . A sequence valve  270  is also visible at the bottom of the probe block  200 . Removing (servicing) the sequence valve  270  requires removal of the probe block  200  from the downhole tool, and then removal of the face seal (not shown) and the filters  240 ,  250 . 
       FIG. 3  is a sectional view of a portion of a conventional auxiliary filter. As illustrated, a peripheral inlet is provided as element  1252 . The filter of the peripheral inlet  1252  is exposed to the wellbore fluid when the probe is in a position used for conveyance. The filter may be plugged by debris present in the wellbore fluid. In order to clean out the debris in the conventional auxiliary filter, the flow through the tool must be reversed to dislodge the materials present on the filter. This clean out procedure prevents progression of tool use in the downhole environment, therefore impacting overall efficiency. 
     In accordance with aspects of the present disclosure, a wellsite with associated wellbore and apparatus is described in order to describe a typical, but not limiting, embodiment of the application. To that end, apparatus at the wellsite may be altered, as necessary, due to field considerations encountered. 
       FIG. 11  illustrates a wellsite system in which aspects of the present disclosure may be implemented. The wellsite can be onshore or offshore. A drill string  105  may extend from a drill rig  101  into a well  110  penetrating a zone of the formation of reservoir  115 . The drill string  105  may employ a mud pulse telemetry system for transmitting data from downhole to the surface. The drill string  105  may also employ another type of telemetry system or any combination of telemetry systems, such as electromagnetic, mud pulse, acoustic and\or wired drill pipe. 
     A bottom hole assembly is suspended at the end of the drill string  105 . The bottom hole assembly may include one downhole tool, an assembly of downhole tools, or a string of downhole tools. In the illustrated example, the drill string  105  may include well logging tools  125  coupled to a lower end thereof. As used herein, the term well logging tool or a string of such tools, may include at least one or more measurement while drilling tools (“MWD”), logging while drilling tools (“LWD”), formation evaluation tools, formation sampling tools and other tools capable of measuring a characteristic of the subterranean formations of the reservoir  115  and\or of the well. In an embodiment, the bottom hole assembly comprises a plurality of MWD or LWD downhole tools  125 , such as indicated by reference numerals  6 A,  6 B. For example, one or more of the downhole tools  6 A,  6 B may be a formation pressure while drilling tool. 
     Logging while drilling tools used at the end of the drill string  105  may include a thick walled housing, commonly referred to as a drill collar, and may include one or more of a number of logging devices. The logging while drilling tools may be capable of measuring, processing, and/or storing information therein, as well as communicating with equipment disposed at the surface of the well site. 
     Measurement while drilling tools may include one or more of the following measuring tools: a modulator, a weight on bit measuring device, a torque measuring device, a vibration measuring device, a shock measuring device, a stick slip measuring device, a direction measuring device, an inclination measuring device, and\or any other device. 
     Measurements made by the bottom hole assembly or other tools and sensors along the drill string  105  may be transmitted to a surface computing system  185  for analysis. For example, mud pulses may be used to broadcast formation measurements performed by one or more of the downhole tools  6 A and  6 B to the surface computing system  185 . 
     The surface computing system  185  may host a plurality of models, such as a reservoir model, to acquire and process data from downhole components, as well as determine the bottom hole location in the reservoir  115  from measurement while drilling data. 
     A derrick or similar device may be used to move the drill string  105  within the well  110  that is being drilled through subterranean formations of the reservoir, generally at  115 . The drill string  105  may be extended into the subterranean formations with a number of coupled drill pipes (one of which is designated  120 ) of the drill string  105 . The drill pipe comprising the drill string  105  may be structurally similar to ordinary drill pipes, and may include a wire or cable associated with each drill pipe  120  that serves as a communication channel. 
     Several of the components disposed proximate to the drill rig  101  may be used to operate components of the system. The drill string  105  may be used to turn and actually urge a drill bit  116  into the bottom of the well  110  to increase its length (depth). During drilling of the well  110 , a pump  130  lifts drilling fluid (mud)  135  from a tank  140  or pits and discharges the mud  135  under pressure through a standpipe  145  and flexible conduit  150  or hose, through a top drive  155  and into an interior passage inside the drill pipe  105 . The mud  135  which can be water or oil-based, exits the drill pipe  105  through courses or nozzles (not shown separately) in the drill bit  116 , wherein it cools and lubricates the drill bit  116  and lifts drill cuttings generated by the drill bit  116  to the surface of the earth through an annular arrangement. 
     When the well  110  has been drilled to a selected depth, the well logging tools  125  may be positioned at the lower end of the drill string  105  if not previously installed. The well logging tools  125  may be positioned by pumping the well logging tools  125  down the drill string  105  or otherwise moving the well logging tools  125  down the drill string  105  while the drill string  105  is within the well  110 . The well logging tools  125  may then be coupled to an adapter sub  160  at the end of the drill string  105  and may be moved through, for example in the illustrated embodiment, a highly inclined portion  165  of the well  110 , which would be inaccessible using armored electrical cable to move the well logging tools  125 . 
     During well logging operations, the pump  130  may be operated to provide fluid flow to operate one or more turbines in the well logging tools  125  to provide power to operate certain devices in the well logging tools  125 . However, when tripping in or out of the well  110 , it may be infeasible to provide fluid flow. As a result, power may be provided to the well logging tools  125  in other ways. For example, batteries may be used to provide power to the well logging tools  125 . In an embodiment, the batteries may be rechargeable batteries and may be recharged by turbines during fluid flow. The batteries may be positioned within the housing of one or more of the well logging tools  125 . Other manners of powering the well logging tools  125  may be used including, but not limited to, one-time power used batteries. 
     As the well logging tools  125  are moved along the well  110  by moving the drill string  105 , signals may be detected by various devices, of which non-limiting examples may include a resistivity measurement device, a bulk density measurement device, a porosity measurement device, a formation capture cross-section measurement device  170 , a gamma ray measurement device  175  and a formation fluid sampling tool  610 ,  710 ,  810  which may include a formation pressure measurement device  6 A and/or  6 B. The signals may be transmitted toward the surface of the earth along the drill string  105 . 
     An apparatus and system for communicating from the drill string  105  to the surface computer  185  or other component configured to receive, analyze, and/or transmit data may include a second adapter sub  190  that may be coupled between an end of the drill string  105  and the top drive  155  that may be used to provide a communication channel with a receiving unit  195  for signals received from the well logging tools  125 . The receiving unit  195  may be coupled to the surface computer  185  to provide a data path therebetween that may be a bidirectional data path. 
     Though not shown, the drill string  105  may alternatively be connected to a rotary table, via a Kelly, and may suspend from a traveling block or hook, and additionally a rotary swivel. The rotary swivel may be suspended from the drilling rig  101  through the hook, and the Kelly may be connected to the rotary swivel such that the Kelly may rotate with respect to the rotary swivel. The Kelly may be any mast that has a set of polygonal connections or splines on the outer surface type that mate to a Kelly bushing such that actuation of the rotary table may rotate the Kelly. 
     An upper end of the drill string  105  may be connected to the Kelly, such as by threadingly reconnecting the drill string  105  to the Kelly, and the rotary table may rotate the Kelly, thereby rotating the drill string  105  connected thereto. 
     Although not shown, the drill string  105  may include one or more stabilizing collars. A stabilizing collar may be disposed within or connected to the drill string  105 , in which the stabilizing collar may be used to engage and apply a force against the wall of the well  110 . This may enable the stabilizing collar to prevent the drill string  105  from deviating from the desired direction for the well  110 . For example, during drilling, the drill string  105  may “wobble” within the well  110 , thereby allowing the drill string  105  to deviate from the desired direction of the well  110 . This wobble action may also be detrimental to the drill string  105 , components disposed therein, and the drill bit  116  connected thereto. A stabilizing collar may be used to minimize, if not overcome altogether, the wobble action of the drill string  105 , thereby possibly increasing the efficiency of the drilling performed at the wellsite and/or increasing the overall life of the components at the wellsite. 
     One or more aspects of the present disclosure may provide a probe block comprising a dynamic filter that can be scraped clean while the probe block is downhole. The filter may be positioned at a fluid entry point in the probe block to decrease the chance of the flow line plugging. In another aspect, fluid may enter all around the filter, making the flow and/or the debris accumulation more uniform, which also reduces the risk of plugging. 
     One or more aspects of the present disclosure may provide a probe block with fewer parts than conventional apparatus, thereby making the probe block easier to assemble. In one aspect, the auxiliary filter is “added” to the original set piston. The probe block may comprise fewer o-rings and fewer face seals than conventional apparatus. 
     One or more aspects of the present disclosure may provide a sequence valve installed from the bottom of the probe block such that the sequence valve and the filter can be removed while the probe block is installed in the probe module, thereby making the probe block easier to maintain than conventional apparatus. 
       FIG. 1  is a sectional view of a probe block  1  with an auxiliary filter  66  according to one or more aspects of the present disclosure. The auxiliary filter  66  is provided on a set piston  15  in a probe assembly to be used downhole as provided in  FIG. 11 . As the set piston  15  is pressed up against the borehole wall, for example, the auxiliary filter  66  is “opened” and the fluid can start being pulled in through the auxiliary filter  66  so that the fluid may be effectively filtered. As the set piston  15  is being retracted, an auxiliary scraper  44  cleans the face of the auxiliary filter  66 . Thus, the position of the set position  15  allows for the auxiliary scraper  44  to be used or stored as needed. 
       FIG. 4  is a schematic sectional view of the probe block  1  according to one or more aspects of the present disclosure, the probe block  1  depicted in a retracted or closed position. A filter piston  42  allows for actuation of a scraper  44 . When the probe block  1  is positioned next to a subterranean formation, for example, probe extension pistons  48  extend, thereby allowing for scraper  44  actuation. A sequence valve  50  is positioned with a hydraulic set line  52  to allow for hydraulic actuation of a fluid chamber, as illustrated in  FIG. 5 , for opening of the entire probe block  1 . A hydraulic retract line  88  is also positioned to withdraw fluid from the sequence valve  50  to allow for refraction of the set piston  15 . A primary filter  90  is positioned on the inside surface of the filter piston  42 . 
       FIG. 5  is a schematic sectional view of the probe block  1  of  FIG. 4  in an extended or opened position. The main flow line  54  is configured to accept fluid flow from the subterranean formation. A central inlet  56  is positioned with inner packers  58  on the periphery. Fluid may flow through the main flow line  54  for further use within the tool. Outer packers  60  are also positioned to abut the subterranean formation to provide additional assurance of seal integrity. In the open position, the chamber  62  is expanded, thus allowing fluid to not only enter through the main flow line  54 , but also through the auxiliary flow line  64 . During motion of the filter piston  42 , a scraper  44  contacts the outer face of the auxiliary filter  66  positioned on the periphery. The scraper  44  may be made of metal or plastic for wear. In the illustrated embodiment, the scraper  44  is made of metal for capabilities to withstand elevated downhole temperatures. For stability of the entire design, probe extension pistons  48  extend and abut a tool, allowing the outer packers  60  and inner packers  58  to abut the subterranean formation and withdraw fluid. 
     In the open configuration depicted in  FIG. 5 , fluid flows from the formation though the auxiliary filter  66  through the central inlet  56 . The filter  66  correspondingly filters the incoming fluid that passes down through the auxiliary flow line  64 . A set of peripheral inlets  78  allows fluid from the subterranean formation to flow in through the auxiliary filter  66 . 
       FIG. 6  is a schematic perspective view, partially in transparency, of a portion of the probe block  1  according to one or more aspects of the present disclosure. In one aspect, vertical machined slots  80  may be placed into the set piston  15  for large scale filtering purposes. 
       FIG. 7  is a schematic perspective view, partially in transparency and partially in cross section, of a portion of the probe block  1  according to one or more aspects of the present disclosure. In this cross-sectional view, the interior of the filter  66  and the scraper  44  are provided. The formation fluid from the subterranean formation can enter the probe block  1  all around the auxiliary filter  66 . The fluid is then collected in a circumferential groove machined in the filter piston  42  that is in fluid communication with the filter slots  80 . The fluid can then proceed through holes  70  drilled across the scraper  44 . 
       FIGS. 8 and 9  provide cross-sectional views of the probe block  1  wherein the auxiliary filter  66  is scraped clean when the filter piston  42  is retracted into the probe block  1 .  FIG. 8  depicts the filter piston  42  before it is retracted into the probe block  1 , and  FIG. 9  depicts the filter piston  42  partially retracted into the probe block  1 . As the filter piston  42  retracts, the auxiliary filter  66  engages and moves past the scraper  44 , which remains stationary and scrapes the auxiliary filter  66  clean. 
       FIG. 10  is a perspective view, partially in transparency, of a portion of the probe block  1  with the sequence valve  50  therein according to one or more aspects of the present disclosure. The sequence valve  50  is provided such that it may be installed from the bottom of the probe block  1 . 
     In accordance with one aspect of the disclosure, an apparatus including a downhole tool for conveyance in a wellbore extending into a subterranean formation is disclosed. The downhole tool includes a focused sampling probe that includes a piston movable between an open position and a closed position, an auxiliary filter coupled to the piston, and a scraper that interfaces with the auxiliary filter. Movement of the piston may cause the auxiliary filter to move against the scraper. The focused sampling probe may further include a sequence valve in fluid communication with the piston. Fluid flow through the sequence valve may move the piston from the closed position to the open position. The focused sampling probe may further include a hydraulic retract line coupled to the sequence valve. The hydraulic retract line may withdraw fluid through the sequence valve to move the piston from the open position to the closed position. 
     In accordance with another aspect of the disclosure, an apparatus including a downhole tool for conveyance in a wellbore extending into a subterranean formation is disclosed. The downhole tool includes a focused sampling probe that includes an auxiliary filter and a scraper that slidingly engages the auxiliary filter. Relative movement between the auxiliary filter and the scraper may clean an outer face of the auxiliary filter. The focused sampling probe may further include a piston coupled to the auxiliary filter. The piston may be moveable between an open position and a closed position. The focused sampling probe may further include a sequence valve in fluid communication with the piston. Fluid flow through the sequence valve in a first direction may move the piston from the closed position to the open position, and fluid flow through the sequence valve in a second direction may move the piston from the open position to the closed position. 
     In accordance with another aspect of the disclosure, a method is disclosed that includes positioning a tool near a subterranean formation, actuating a piston from a first closed position to a second open position, during the actuation of the piston, scraping an exterior face of a filter, and accepting a flow of fluid from the subterranean formation through the filter. The method may further include accepting a flow of fluid from the subterranean formation through an auxiliary flow line. 
     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. 
     The Abstract at the end of this disclosure is provided to comply with 37 C.F.R. §1.72(b) to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.