Patent Publication Number: US-11391125-B2

Title: Method and system of self-contained replaceable filtration screen with high performance for oil and gas wells

Description:
BACKGROUND 
     When drilling a well, the well may travel through different types of poorly consolidated formations. Such formations may include, for example, high permeability formations containing sand and/or other fine solids. When drilling through poorly consolidated formations, the industry conventionally uses a gravel packing technique that involves pumping gravel downhole and around a perforated liner to create a gravel filter between the borehole wall and the perforated liner. 
       FIGS. 1-3  show an example of a conventional gravel packing process in a poorly consolidated section  11  of a well  10 , such as a sand formation. In  FIG. 1 , a perforated and/or screened liner  12  and liner hanger  13  is sent downhole using a liner hanger setting tool  14  to the poorly consolidated section  11  of the well  10 . In  FIG. 2 , the liner hanger  13  is set at the end of a casing  15  lining a portion of the well  10 . Setting the liner hanger  13  may include radially expanding one or more slips  16  or packing elements on the liner hanger  13  to contact the inner surface of the casing  15 . Once set, gravel  16  is pumped downhole out of gravel ports  18  through the liner  12  to fill the annulus  17  between the borehole wall and the liner  12 . Water or other fluid may be mixed with the gravel  16  to aid in pumping the gravel  16  around the exterior of the liner  16 . In  FIG. 3 , once gravel packing is complete, the well  10  is ready for sand-free production. 
     Conventional gravel packing processes may incur issues with pressure while pumping, which may result in not enough gravel being packed between the wellbore and liner and/or increased completion time. Further, when drilling horizontal or directional sections of a well through poorly consolidated formations, gravel may be unevenly distributed around the liner. 
     SUMMARY 
     This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. 
     In one aspect, embodiments of the present disclosure relate to methods for completing a well that include packing gravel in an annular space between an inner slotted basket and an outer slotted basket to form a packed filtration screen assembly, attaching the packed filtration screen assembly around a perforated portion of a liner, sending the liner and attached packed filtration screen assembly into the well, and hanging the liner from an end of a casing lining the well to position the packed filtration screen assembly in an open hole portion of the well below the end of the casing. 
     In another aspect, embodiments of the present disclosure relate to systems for completing a well that include a packed filtration screen assembly having an inner slotted basket, an outer slotted basket positioned concentrically around the inner slotted basket, gravel held in an annular space between the inner slotted basket and the outer slotted basket, and axial end caps located at opposite axial ends of the annular space, wherein the packed filtration screen assembly may be removably attached to around a perforated portion of a liner. 
     Other aspects and advantages will be apparent from the following description and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Wherever possible, like or identical reference numerals are used in the figures to identify common or the same elements. The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale for purposes of clarification. 
         FIGS. 1-3  show steps in a conventional gravel packing process. 
         FIG. 4  shows a filtration screen assembly being packed with a filtration medium according to embodiments of the present disclosure. 
         FIG. 5  shows a zoomed view of a slotted basket according to embodiments of the present disclosure. 
         FIG. 6  shows a perspective view of a packed filtration screen assembly according to embodiments of the present disclosure. 
         FIG. 7  shows an example of a perforated liner around which a packed filtration screen assembly may be attached according to embodiments of the present disclosure. 
         FIG. 8  shows a packed filtration screen assembly attached to a perforated liner according to embodiments of the present disclosure. 
         FIG. 9  shows a deconstructed view of packed circumferential sections of a packed filtration screen assembly according to embodiments of the present disclosure. 
         FIG. 10  shows the packed circumferential sections of  FIG. 9  attached together around a liner according to embodiments of the present disclosure. 
         FIG. 11  shows a diagram of a packed filtration screen assembly in use in a well operation according to embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     As used herein, the term “coupled” or “coupled to” or “connected” or “connected to” may indicate establishing either a direct or indirect connection, and is not limited to either unless expressly referenced as such. Further, the terms “lower,” “below,” “bottom,” and the like may be used to describe a position or tool component that, when in a downhole location, is relatively farther away from the surface of the well, while the terms “upper,” “top,” “above,” and the like may be used to describe a position or tool component that, when in a downhole location, is relatively closer to the surface of the well. 
     Embodiments disclosed herein include methods and systems using a self-contained replaceable filtration screen assembly. The filtration screen assembly may be packed with gravel or other filtration medium prior to its use downhole. The packed filtration screen assembly may then be connected around a downhole tubular, such as a liner, and sent downhole for use in production of the well. 
     According to embodiments of the present disclosure, a filtration screen assembly may include an inner slotted basket, an outer slotted basket positioned concentrically around the inner slotted basket, and one or more connecting walls connecting the inner slotted basket and the outer slotted basket together while also providing an annular space between the inner and outer slotted baskets. To pack the filtration screen assembly, gravel or other filtration medium may be poured into the annular space between the inner and outer slotted baskets. The annular space and filtration medium filling may be entirely enclosed between the inner and outer filtration baskets and connecting walls therebetween. 
     For example,  FIG. 4  shows a diagram of a filtration screen assembly  100  being assembled. The filtration screen assembly  100  may include an outer slotted basket  120  connected concentrically around an inner slotted basket  110  by a first axial end cap  130 . The first axial end cap  130  may have a generally toroidal or elliptical ring shape. An outer perimeter of the first axial end cap  130  may be connected to the outer slotted basket  120 , and an inner perimeter of the first axial end cap  130  may be connected to the inner slotted basket  110 , for example, by welding or other connection methods. For example, in some embodiments, the inner perimeter of the first axial end cap  130  may be connected to the inner slotted basket  110  using a threaded connection, and/or the outer perimeter of the first axial end cap  130  may be connected to the outer slotted basket  110  using a threaded connection. In some embodiments, a first axial end cap  130  may be integrally formed with the inner slotted basket  110  or the outer slotted basket  120  and connected to the other of the inner or outer slotted basket  110 ,  120 . 
     The inner and outer slotted baskets  110 ,  120  may have a woven, wire wrapped, or slotted pattern of openings formed through the wall of each of the inner and outer slotted baskets  110 ,  120 . For example,  FIG. 5  shows a perspective view of the inner slotted basket  110 , having a plurality of slots  112  formed through the wall  114  of the basket  110 . The slots  112  may be arranged in a pattern or randomly along the axial length  111  of the inner slotted basket  110 , as measured between the axial ends of the basket  110 . The slots  112  may be formed, for example, by cutting openings through the wall  114  of the basket  110  using an ultra-thin cutting tool or a laser. The slots  112  may have an opening width  116  and extend an opening length  118  that is greater than or equal to the opening width  116 . Slot opening widths  116  may be less than the size of the gravel or other filtration medium  150  packed in the filtration screen assembly  100 , and may range in size, for example, from less than 0.5 inches, less than 0.2 inches, or less than 0.05 inches. In some embodiments having slots  112  extending longitudinally along the axial length  111  of the basket, the opening length  118  of the slots  112  may extend less than half, less than a fourth, less than a tenth, or less than a hundredth of the axial length  111  of the basket  110 . In some embodiments, slots  112  may extend an opening length  118  around the entire or a partial circumference of the basket  110 . 
     Slots  112  formed in the inner slotted basket  110  may have the same sized or differently sized opening widths as slots formed in the outer slotted basket  120 . Further, slots  112  formed in the inner slotted basket  110  may be oriented the same or differently than slots formed in the outer slotted basket  120 . For example, an inner slotted basket  110  may have longitudinally extending slots  112  formed therein, and an outer slotted basket  120  may have circumferentially extending slots formed therein, or vice versa. 
     In some embodiments, slots or other openings may be formed through the inner and/or outer slotted baskets  110 ,  120  that have an opening width that is less than a perforation opening size formed through a perforated liner on which the filtration screen assembly is to be connected. 
     The inner and outer slotted baskets  110 ,  120  may be concentrically aligned such that the longitudinal axes  101  of the inner and outer slotted baskets  110 ,  120  are co-axially aligned, and an annular space  140  between the inner and outer slotted baskets  110 ,  120  has a uniform thickness  142  (as measured radially between the inner and outer slotted baskets) around the entire annular space  140 . The thickness  142  of the annular space  140  may vary, for example, depending on the type and size of the filtration medium, the size of the tubular around which the filtration screen assembly  100  will be connected around, and the size of the well in which the filtration screen assembly  100  will be used. For example, an annular space  140  may have a thickness ranging from a lower limit selected from 0.5 inches, 0.8 inches, 1 inch, and 1.5 inches to an upper limit selected from 1.5 inches, 2 inches, 3 inches, and 4 inches, where any upper limit may be used in combination with any lower limit. In embodiments using a relatively finer filtration medium, the annular space  140  may be designed to have a relatively smaller thickness  142  than when using a relatively coarser filtration medium. 
     A filtration medium  150  may be poured into the annular space  140  defined between the inner and outer slotted baskets  110 ,  120  and the first axial end cap  130 . The filtration medium  150  may be, for example, gravel, beads, or other granularized material. In some embodiments, the filtration medium may be gravel that ranges in size from 1 mm to 2.5 mm in diameter, as measured along its longest dimension. The gravel may have a unimodal, bimodal, or multimodal size distribution. In some embodiments, gravel may be provided as having a narrow range in size, for example, where the standard deviation in size ranges from less than 10 percent, less than 5 percent, or less than 2 percent from the average size of the gravel. 
     The filtration medium  150  may be poured into the filtration screen assembly  100  offsite (e.g., at a factory or other location away from a well site) or onsite near a well. After filling the annular space entirely with the filtration medium  150 , a second axial end cap  160  may be connected at an opposite axial end of the inner and outer slotted baskets  110 ,  120  from the first axial end cap  130  in order to seal and contain the filtration medium  150  inside the annular space  140 . The second axial end cap  160  may have the same or different shape as the first axial end cap  160  and may have a generally toroidal or elliptical ring shape. The second axial end cap  160  may be connected to the inner and outer slotted baskets  110 ,  120 , for example, by welding, a threaded connection, or other latching mechanism. In some embodiments, one of an inner perimeter  162  and an outer perimeter  164  of the second axial end cap  160  may be threaded to the inner or outer slotted basket  110 ,  120 , respectively, where such connection may axially compress the second axial end cap  160  toward the first axial end cap  130 . 
     When gravel or other filtration medium  150  is contained within and fully fills the entire annular space  140  between the inner and outer slotted baskets  110 ,  120  and the first and second axial end caps  130 ,  160 , the filtration screen assembly  100  may be referred to as a packed filtration screen assembly  100 . The packed filtration screen assembly  100  may be removably attached to a downhole tubular such as a liner, for example, using connection clamps. 
       FIGS. 6-8  show an example of steps for connecting a packed filtration screen assembly  200  to a perforated liner  300 . The packed filtration screen assembly  200  may include an inner slotted basket  210 , an outer slotted basket  220 , and connecting walls  230  connecting the axial ends of the inner and outer slotted baskets  210 ,  220 , where gravel is packed and contained within the annular space defined between the inner and outer slotted baskets  210 ,  220  and connecting walls  230 . The inner slotted basket  210  may define a conduit or through hole  205  extending axially through the length of the packed filtration screen assembly  200 . 
     The perforated portion  310  of the liner  300  may have perforation openings  312  with a size greater than the openings formed through the inner and outer slotted baskets  210 ,  220 . The openings formed through the inner and outer slotted baskets  210 ,  220  may be smaller than the size of the gravel packed in the packed filtration screen assembly  200 , such that the gravel may not escape through the openings in the inner and outer slotted baskets  210 ,  220 . 
     According to some embodiments of the present disclosure, the packed filtration screen assembly  200  may be connected to a perforated liner  300  by sliding the packed filtration screen assembly  200  around an axial end  302  of the perforated liner  300 , as represented by arrow  207 . In such embodiments, the through hole  205  of the packed filtration screen assembly  200  may have an inner diameter  204  that is slightly greater than the outer diameter  304  of the axial end  302  of the perforated liner  300 , such that the packed filtration screen assembly  200  may tightly slide around the perforated liner  300  (e.g., where a clearance between the inner diameter  204  of the packed filtration screen assembly  200  and the outer diameter  304  of the perforated liner  300  may be less than 1 inch, less than 0.5 inches, or less than 0.2 inches). 
     The packed filtration screen assembly  200  may be slid axially along the perforated liner  300  to surround a perforated portion  310  of the perforated liner  300 . In the embodiment shown, the perforated liner  300  may have a tubular body  305  having an outer diameter  304  that is substantially uniform along its length from the axial end  302  to throughout the perforated portion  310 , such that the packed filtration screen assembly  200  may fit around both the axial end  302  and the perforated portion  310  of the liner  300 . In some embodiments, the axial end  302  of the liner  300  may have an outer diameter that is less than the outer diameter  304  of the perforated portion  310  of the liner  300 , for example, to allow for a connection to be made to the axial end  302  of the liner  300  after assembling the packed filtration screen assembly  200  to the liner  300 . In such embodiments, both the outer diameter  304  of the perforated portion  310  and the outer diameter of the axial end  302  of the liner  300  are smaller than the inner diameter  204  of the packed filtration screen assembly  200 . 
     As shown in  FIG. 8 , once the packed filtration screen assembly  200  is slid onto the liner  300  and in a position entirely surrounding the perforated portion  310  of the liner  300 , a lower clamp  322  may be attached around the liner  300  at a lower axial end of the packed filtration screen assembly  200 , and an upper clamp  324  may be attached around the liner  300  at an upper axial end of the packed filtration screen assembly  200 . The lower and upper clamps  322 ,  324  may be friction-fitted at the lower and upper axial ends, respectively, of the packed filtration screen assembly  200  to hold the packed filtration screen assembly  200  in place. In some embodiments, the lower and upper axial ends of the packed filtration screen assembly  200  may be welded to the liner  300  to hold the packed filtration screen assembly  200  in place. Other methods of attaching the packed filtration screen assembly  200  to the liner  300  may be used to hold the packed filtration screen assembly  200  around the perforated portion  310  of the liner  300 . 
     After the packed filtration screen assembly  200  is attached to the liner  300 , additional components may be attached to one or both axial ends of the liner  300  to send downhole for a production operation. For example, a sand trap, bull plug, or an additional liner pipe may be connected to the axial end  302  of the liner  300  below the packed filtration screen assembly  200 , and a liner hanger or an additional liner pipe may be connected to an opposite axial end  306  of the liner  300 . The axial ends  302 ,  306  of the liner  300  may be threaded connections, for example, a pin end and a box end, or may have other connection features known in the art for tubular connections. 
     In some embodiments, a packed filtration screen assembly may be packed in circumferential sections, which once packed, may be assembled and attached around a perforation portion of a tubular. The circumferential sections may be fully self-contained and individually packed prior to assembling around the perforated portion of the tubular. For example, gravel or other filtration medium may be fully enclosed within a space defined by an inner slotted basket circumferential section, an outer slotted basket circumferential section, and radial walls extending between and connecting the inner and outer slotted basket circumferential sections to form a packed circumferential section of a packed filtration screen assembly. 
     Two or more packed circumferential sections may be attached around a perforated portion of a tubular, such as a perforated liner, for example, by welding the packed circumferential sections together and to the tubular and/or by using one or more connection mechanisms such as a clamp or latch to connect the packed circumferential sections together and to the tubular. 
     For example,  FIG. 9  shows a deconstructed view of two packed circumferential sections  400  of a packed filtration screen assembly, where each packed circumferential section  400  may form a half of the packed filtration screen assembly when assembled. In other embodiments, more than two packed circumferential sections may form equi-portioned circumferential sections of a packed filtration screen assembly. 
     A packed circumferential section  400  may include an inner slotted basket circumferential section  402 , an outer slotted basket circumferential section  404 , and an annular space between the inner and outer slotted basket circumferential sections  402 ,  404 . The annular space may have a uniform thickness along the entire circumferential section  400 , where the annular space thickness is measured along a radial dimension between the inner and outer slotted basket circumferential sections  402 ,  404 . The annular space may be filled with gravel  406  or other filtration medium. Radial walls  401  may be attached at the sides of the circumferential section  400 , which may enclose the gravel  406  in the annular space along the sides of the circumferential section. The radial walls  401  may extend between the inner slotted basket circumferential section  402  and the outer slotted basket circumferential section  404 , or may be attached to and cover the sides of the inner and outer slotted basket circumferential sections  402 ,  404  and the annular space therebetween. Further, axial end caps  403  may be attached at opposite axial ends of the annular space to enclose the gravel  406  in the annular space along the axial ends of the circumferential section  400 . 
     Packed circumferential sections  400  may be assembled, for example, by providing multiple circumferential sections of an inner slotted basket  402  and an outer slotted basket  404 , which are connected together using one or more connecting walls (e.g., radial walls  401  and axial end caps  403 ) to define an annular space in which gravel may be contained. Gravel  406  may be filled in the annular space in each of the multiple circumferential sections  400  and entirely enclosed with the connecting walls between the inner and outer slotted basket circumferential sections  402 ,  404 . After each of the circumferential sections  400  are packed with gravel  406  and enclosed, the multiple packed circumferential sections  400  may be fitted together around a tubular to attach the packed filtration screen assembly to the tubular. 
     Slotted baskets and connecting walls forming packed filtration screen assemblies may be formed, for example, of a corrosion resistant material, such as stainless steel, aluminum alloys, and galvanized steel. 
     As shown in  FIG. 10 , when the packed circumferential sections  400  are attached together around a tubular (e.g., a perforated liner)  410 , the packed filtration screen assembly  420  may extend entirely around the circumference of the tubular  410 , divided by the radial walls  401  at equidistant circumferential locations. The packed circumferential sections  400  may be attached together and attached around the tubular  410 , for example, by welding, clamps, or other attachment mechanism. 
     According to embodiments of the present disclosure, packed filtration screen assemblies may be used in well completion operations. For example, methods of completing a well may include attaching a packed filtration screen assembly around a perforated portion of a liner, sending the liner and attached packed filtration screen assembly into the well, and hanging the liner from an end of a casing lining the well, wherein the packed filtration screen assembly is positioned in an open hole portion of the well below the end of the casing. The packed filtration screen assembly around the perforated liner may filter sand or other fine solids such as silt from a poorly consolidated formation surrounding the liner from entering the liner. The packed filtration screen assembly may be packed with gravel or other filtration medium that is selected, for example, based on the type of formation in which the packed filtration screen assembly is used in. The gravel may be packed in the filtration screen assembly prior to bringing the packed filtration screen assembly to the well site, or at the well site. 
     For example, referring to  FIG. 11  showing an example of a stage of a well  500  completion operation, one or more casings  510  may extend from a wellhead  501  to a depth in the well  500 . The casings  510  may be set in the well  500 , for example, by cementing the casings  510  in the well  500 . A packed filtration screen assembly  530  according to embodiments of the present disclosure may be attached around a perforated portion of a liner  520  and sent downhole through the well casing  510 . For example, the liner  520  may be sent downhole using a running tool. 
     The liner  520  may have a liner hanger  540  attached axially above the attached packed filtration screen assembly  530 . The liner  520  may be sent into an open hole portion of the well  500 , such that the liner  520  may extend from an end  511  of the casing  510  to a second depth in the well  500 . The liner hanger  540  may be attached to the end  511  of the casing  510 , thereby hanging the liner  520  from the end of the casing  510  and positioning the attached packed filtration screen assembly  530  within the open hole portion of the well  500 . The attached packed filtration screen assembly  530  may filter fine solids that may flow from the formation  502  along with production fluids. 
     Once the packed filtration screen assembly  530  is positioned in the well  500  on the attached liner  520 , an acid (e.g., hexa-meta-phosphate) may be pumped through the liner  520  to prepare and start enhancing the well  500  for production. 
     A pump may then be run downhole to pump fluids produced from the well  500  that flow from the open hole portion of the well  500 , through the packed filtration screen assembly  530  and perforated portion of the liner  520  to the surface of the well  500 . 
     According to embodiments of the present disclosure, a packed filtration screen assembly  530  may be returned to the surface of the well  500 , for example, for repair, replacement, or when the production is complete. Methods of returning the packed filtration screen assembly  530  may include detaching the liner  520  from the casing  510 , returning the liner  520  and attached packed filtration screen assembly  530  to the surface of the well  500  (e.g., using a running tool), and removing the packed filtration screen assembly  530  from the liner  520 . 
     In some embodiments, after a packed filtration screen assembly  530  is removed from the liner  520 , the packed filtration screen assembly  530  may be reused. For example, the used packed filtration screen assembly  530  may be attached around different tubular, such as a second perforated liner, or may be reattached to the perforated liner  520  and sent back downhole. 
     According to some embodiments, when a packed filtration screen assembly  530  is reused, the packed filtration screen assembly  530  may be at least partially disassembled, for example, to be repaired, to be cleaned, and/or have the filtration medium replaced. For example, in some embodiments, the filtration medium may be emptied from the packed filtration screen assembly  530  and replaced with a different type and/or size of filtration medium. 
     After a used packed filtration screen assembly  530  is reattached to a liner  520 , the liner  520  and reattached packed filtration screen assembly  530  may be sent downhole, for example, in the same well  500  or in a different well for another completion operation. 
     In the embodiment shown in  FIG. 11 , the liner  520  and attached packed filtration screen assembly  530  may be installed in a vertical section of a well  500 . However, packed filtration screen assemblies according to embodiments of the present disclosure may also be installed in directional wells, for example, in a horizontal section of a well. 
     By using packed filtration screen assemblies according to embodiments of the present disclosure, completion time may be minimized when compared to conventional methods of pumping gravel in and around perforated liners installed downhole. Further, by pre-packing filtration screen assemblies as disclosed herein, the appropriate amount of gravel or other filtration medium may be predetermined and used in a packed filtration screen assembly to assure successful filtration without plugging. 
     While the present disclosure has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments may be devised which do not depart from the scope of the disclosure as described herein. Accordingly, the scope of the disclosure should be limited only by the attached claims.