WO2020005576A1

WO2020005576A1 - Landing assemblies for a subterranean wellbore

Info

Publication number: WO2020005576A1
Application number: PCT/US2019/037173
Authority: WO
Inventors: John Chrysostom Wolf; Aju Abraham; David NOWOWIEJSKI
Original assignee: National Oilwell Varco, L.P.
Priority date: 2018-06-29
Filing date: 2019-06-14
Publication date: 2020-01-02

Abstract

Disclosed herein are landing assemblies for use within a subterranean wellbore. In some embodiments, the landing sub includes central landing assembly disposed within an outer housing such that an annulus is formed therebetween. The central landing assembly includes a first landing surface, a first plurality of ports, and a second plurality of ports. The first plurality of ports is disposed on an axially opposite side of the first landing surface from the second plurality of ports. The central landing assembly is configured to actuate from a first position, in which the second plurality of ports are not in fluid communication with the annulus, to a second position in which the second plurality of ports are in fluid communication with the annulus, upon engagement of a first flowable valve member with the first landing surface.

Description

LANDING ASSEMBLIES FOR A SUBTERRANEAN WELLBORE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims benefit of U.S. Provisional Patent Application No. 62/692,428, filed June 29, 2018, and entitled“Landing Assembly For A Subterranean Wellbore,” which is hereby incorporated herein by reference in its entirety for all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not applicable.

BACKGROUND

[0003] Flowable valve members, such as darts, wipes, pigs, balls, etc. are flowed through tubular strings (e.g., casing strings, production tubing, etc.) disposed within subterranean wellbores (such as those used to access and product oil and gas reserves within subterranean formations) to perform a variety of functions. One potential use of such flowable valve members is to provide a movable fluid barrier between two different fluids within the wellbore tubular, such as, for example, when one fluid is being displaced from the wellbore tubular by a second fluid. To facilitate the use of the flowable valve members within the wellbore tubular, landing surfaces may be provided that capture and retain the flowable valve members at a desired locations downhole.

BRIEF SUMMARY OF THE DISCLOSURE

[0004] Some embodiments disclosed herein are directed to a landing assembly for use within a subterranean wellbore. In an embodiment, the landing assembly includes an outer housing having a central axis and configured to be coaxially coupled to a tubular string. In addition, the landing assembly includes a central landing assembly disposed within the outer housing, the central landing assembly including a first landing surface and a second landing surface that is axially uphole of the first landing surface. The central landing assembly is configured to actuate from a first position to a second position, upon engagement of a first flowable valve member with the first landing surface. In addition, the second landing surface is configured to translate radially inward toward the central axis when the central landing assembly actuates from the first position to the second position.

[0005] Other embodiments disclosed herein are directed to a landing assembly for use within a subterranean wellbore. In an embodiment, the landing assembly includes an outer housing having a central axis and configured to be coaxially coupled to a tubular string. In addition, the landing assembly includes a central landing assembly disposed within the outer housing, and an annulus between the outer housing and the central landing assembly. The central landing assembly includes a first landing surface, a first plurality of ports, and a second plurality of ports. The first plurality of ports is disposed on an axially opposite side of the first landing surface from the second plurality of ports. In addition, the central landing assembly is configured to actuate from a first position, in which the second plurality of ports are not in fluid communication with the annulus, to a second position in which the second plurality of ports are in fluid communication with the annulus, upon engagement of a first flowable valve member with the first landing surface.

[0006] Still other embodiments disclosed herein are directed to a method for flowing fluid within a subterranean wellbore. In an embodiment, the method includes (a) coupling a landing assembly to a tubular string, the landing assembly having a central axis and (b) inserting the landing assembly and the tubular string within a subterranean wellbore. In addition, the method includes (c) flowing a first flowable valve member into the tubular string and (d) landing the first flowable valve member on a first landing surface within the landing assembly. Further, the method includes (e) opening a bypass flow path as a result of (d), wherein the bypass flow path extends from a first plurality of ports in the landing assembly that are uphole of the first landing surface to a second plurality of ports in the landing assembly that are downhole of the first landing surface. Still further, the method includes (f) flowing a second flowable valve member into the tubular string, (g) landing the second flowable valve member on a second landing surface, and (h) closing the bypass flow path as a result of (g).

[0007] Embodiments described herein comprise a combination of features and characteristics intended to address various shortcomings associated with certain prior devices, systems, and methods. The foregoing has outlined rather broadly the features and technical characteristics of the disclosed embodiments in order that the detailed description that follows may be better understood. The various characteristics and features described above, as well as others, will be readily apparent to those skilled in the art upon reading the following detailed description, and by referring to the accompanying drawings. It should be appreciated that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes as the disclosed embodiments. It should also be realized that such equivalent constructions do not depart from the spirit and scope of the principles disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] For a detailed description of various exemplary embodiments, reference will now be made to the accompanying drawings in which:

[0009] Figure 1 is a schematic view of a wellbore system in accordance with at least some embodiments disclosed herein;

[0010] Figures 2-5 are sequential schematic views of a cementing operation for the wellbore system of Figure 1 ;

[0011] Figure 6 is a side cross-sectional view of an embodiment of a landing sub for use within the wellbore system of Figure 1 in accordance with at least some embodiments disclosed herein;

[0012] Figure 7 is an enlarged cross-sectional view of one of the dogs of the landing sub of Figure 6;

[0013] Figures 8 and 9 are sequential enlarged side cross-sectional views of a dart landing operation using the landing sub of Figure 6;

[0014] Figure 10 is a side cross-sectional view of an embodiment of a landing sub for use within the wellbore system of Figure 1 in accordance with at least some embodiments disclosed herein;

[0015] Figures 1 1 and 12 are sequential enlarged side cross-sectional views of a dart landing operation using the landing sub of Figure 10;

[0016] Figure 13 is a side cross-sectional view of an embodiment of a landing sub for use within the wellbore system of Figure 1 in accordance with at least some embodiments disclosed herein; [0017] Figures 14 and 15 are sequential enlarged side cross-sectional views of a dart landing operation using the landing sub of Figure 13;

[0018] Figure 16 is a side cross-sectional view of an embodiment of a landing sub for use within the wellbore system of Figure 1 in accordance with at least some embodiments disclosed herein;

[0019] Figures 17 and 18 are sequential enlarged side cross-sectional views of a dart landing operation using the landing sub of Figure 16;

[0020] Figure 19 is a side cross-sectional view of an embodiment of a landing sub for use within the wellbore system of Figure 1 in accordance with at least some embodiments disclosed herein; and

[0021] Figure 20 is an enlarged side cross-sectional view of a dart landing operation using the landing sub of Figure 19.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0022] The following discussion is directed to various exemplary embodiments. Flowever, one of ordinary skill in the art will understand that the examples disclosed herein have broad application, and that the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment.

[0023] The drawing figures are not necessarily to scale. Certain features and components herein may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in interest of clarity and conciseness.

[0024] In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to... Also, the term“couple” or“couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection of the two devices, or through an indirect connection that is established via other devices, components, nodes, and connections. In addition, as used herein, the terms“axial” and“axially” generally mean along or parallel to a given axis (e.g., central axis of a body or a port), while the terms “radial” and“radially” generally mean perpendicular to the given axis. For instance, an axial distance refers to a distance measured along or parallel to the axis, and a radial distance means a distance measured perpendicular to the axis. Further, any reference to up or down in the description and the claims is made for purposes of clarity, with“up”, “upper”,“upwardly”,“uphole”, or“upstream” meaning toward the surface of the wellbore or borehole and with “down”, “lower”, “downwardly”, “downhole”, or “downstream” meaning toward the terminal end of the wellbore or borehole, regardless of the wellbore or borehole orientation.

[0025] As previously described, flowable valve member s (e.g., darts, balls, etc.) are often used as a movable fluid barrier between two different fluids in a subterranean wellbore tubular. One specific example where such valve members are used is in a cementing operation, during which cement is flowed within the tubular string to secure part or all of the tubular string within the wellbore. During these operations, one or more flowable valve members may be disposed between the pumped cement and any other fluids within the wellbore (e.g., displacement fluid, drilling mud, formation fluids, etc.) to prevent mixing of the cement and the other wellbore fluids. Because the flowable valve member(s) are configured to provide a seal between the two fluids within the tubular string, they can create an obstruction within the wellbore once they are landed in a final location. Such an obstruction can frustrate subsequent wellbore operations (e.g., by preventing adequate fluid flow within the wellbore). Accordingly, embodiments disclosed herein provide landing subs and related assemblies that provide landing surfaces and actuatable bypass flow paths to allow selective flowing of fluid around and past the landed flowable valve members.

[0026] Referring now to Figure 1 , a wellbore system 1 is shown that includes a wellbore 16 extending from the surface 5 into a subterranean formation 14. In this embodiment wellbore 16 includes a vertical portion or section 17 extending from surface 5 and a lateral portion or section 19 extending from vertical section 17. While lateral section 19 is depicted as extending horizontally (or at a 90° angle to the vertical direction) it should be appreciated that lateral section 19 may extend at a number of different angles from vertical section 17 (e.g., such any suitable angle between 0° and 90° relative to the vertical direction in some embodiments). Surface equipment 12 is also disposed at the surface 5 proximate wellbore 14. Surface equipment 12 may comprise any suitable structure, device, or unit for supporting the operations within wellbore 14. Thus, the specific nature and type of surface equipment 12 may change at any given time depending on the operations being conducted in wellbore 14. For example, in some embodiments surface equipment 12 may comprise a drilling rig (e.g., to facilitate drilling operations of wellbore 14), completion equipment (e.g., to facilitate completion operations within wellbore 14), a production tree (e.g., to facilitate production operations from wellbore 14), etc.

[0027] A tubular string (or wellbore tubular) 20 is disposed within wellbore 16 and extends from surface 5 to a terminal or downhole end 26. Tubular string 20 comprises a first or vertical section 22 extending from surface 5 and a second or lateral section 24 extending from vertical section 22 to terminal end 26. As shown in Figure 1 , vertical section 22 of tubular string 20 is disposed within vertical section 17 of wellbore 16 and lateral section 24 of tubular string 20 is disposed within lateral section 19 of wellbore. In this embodiment, tubular string 20 comprises a plurality of elongate tubular members that are coupled end-to-end (e.g., threadably coupled) to form string 20. In this embodiment, tubular string 20 is a casing string and may be simply referred to as casing 20. Flowever, it should be appreciated that tubular string 20 may comprise any suitable tubular string (or plurality of coaxially nested tubular strings) for use within a wellbore (e.g., wellbore 16). When casing 20 is disposed within wellbore 16, a first or upper annulus or annular region 15 is formed between vertical section 22 of casing string 20 and the inner wall of vertical section 17 of wellbore 16, and a second or lower annulus or annular region 13 is formed between lateral section 24 of casing string 20 and the inner wall of lateral section 19 of wellbore 16.

[0028] A landing sub (or landing assembly) 100 is disposed along lateral section 24 of casing 20, within lateral section 19, and proximate downhole end 26. In this embodiment, landing sub 100 comprises one or more elongate tubular members that are threadably engaged between two other of the elongate tubular members forming lateral section 24 of casing 20. Thus, it may be said that landing sub 100 is integral with casing 20. As shown in Figure 1 , landing sub 100 comprises a first or lower landing surface or seat 102. As will be described in more detail below, seat 102 is configured to engage with and capture a flowable valve member that may be dropped and/or flowed through wellbore 16 from surface 5 to seat 102. The flowable valve member may comprise any suitable device, shape, or design, such as, for example, a ball, a dart, a plug, etc. In the discussion that follows, the flowable valve member is a dart, but this is merely for explanation and should not be interpreted as limiting all uses of landing sub 100 (or any embodiments thereof) to those utilizing a dart within wellbore 16.

[0029] Referring still to Figure 1 , after initially inserting casing string 20 within the wellbore 16, it may be desirable to secure string 20 within wellbore 16 with cement. In particular, cement is placed in the annuluses 13, 15, which secures casing 20 to the inner wall of wellbore 16 upon hardening. In addition, the hardened the cement also prevents (or at least restricts) the uncontrolled migration of hydrocarbons and other formation fluids from subterranean formation 14 into the annuluses 13, 15 (and thereafter to the surface 5). As a result, a quality cementing operation can be key to ensuring safe and controlled production operations from wellbore 16. An example cementing operation for cementing lateral section 24 of casing 20 within lateral section 19 of wellbore 16 will now be discussed with general reference to Figure 2-5. In the described cementing operations, only lateral section 24 of casing 20 is cemented within lateral section 19 of wellbore 16; however, it should be appreciated that the operations described herein are relevant for cementing operations for vertical section 22 within vertical section 17 of wellbore 16, and/or simultaneous cementing of both sections 22, 24 of casing 20 within sections 17, 19, respectively, of wellbore 16.

[0030] Referring now to Figure 2, the cementing operation begins by inserting a first dart 60 (e.g., a flowable valve member as previously described) into casing 20 at surface 5 (e.g., via surface equipment 12) and displacing dart 60 downhole with cement 54. Dart 60 is configured to sealingly engage with the inner walls of casing 20 so that fluids 52 disposed within casing 20 at the initiation of the cementing operation are displaced out of terminal end 26, into annuluses 13, 15, and finally to surface 5. The fluids 52 initially disposed within casing 20 and annuluses 13, 15 may comprise a number of different fluids or combinations thereof, such as, for example, drilling mud, water, formation fluids, etc. It is often desirable to displace fluids 52 from the casing 20 during a cementing operation so that substantial mixing of the cement 54 and fluids 52 does not occur which may result in an incomplete packing of cement within the annulus (annulus 13). Thus, dart 60 acts as a fluid barrier between fluids 52 and cement 54 as the cement 54 is advanced within casing 20 toward terminal end 26.

[0031] Referring now to Figure 3, eventually the desired charge of cement 54 is fully inserted within casing 20 (which may comprise the amount of cement 54 that will be sufficient to fill the desired section of annulus - which in this embodiment is annulus 13). As a result, a second dart 62 is inserted within casing 20 that is displaced downhole with fluid 56, which may comprise any suitable fluid for displacing darts 60, 62 and cement 54 downhole within casing 20. For example, in some embodiments, displacement fluid 56 may comprise any one or more of drilling mud, oil, water, etc., and may be the same (or substantially the same) as fluid 52. As with first dart 60, second dart 62 sealingly engages with the inner walls of casing 20 such that second dart 2 provides a fluid barrier between mud 54 and displacement fluid 56 during operations. Therefore, at this stage in the cementing operation (i.e. , the stage shown in Figure 3), the cement 54 is disposed within casing 20 (e.g., within lateral section 24 of casing 20) and is captured between darts 60, 62.

[0032] Referring now to Figure 4, as cement 54 and darts 60, 62 continue to be displaced within casing 20, eventually first dart 60 lands on seat 102 within landing sub 100. As will be described in more detail below, in some embodiments, engagement of first dart 60 and seat 102 causes landing sub 100 to actuate and thereby deploy a second or upper landing seat 104 that is uphole of the engaged first dart 60 and seat 102. In other embodiments, uphole landing seat 104 may already be fixed and deployed within landing sub 100 when first dart 102 passes therethrough, and (in these embodiments) first dart 60 is sized and/or shaped so that it may freely pass by uphole seat 104 and land on downhole seat 102. As will also be described in more detail below, other embodiments of landing sub 100 may only include a single landing seat, such as for cementing operations that utilize only a single dart.

[0033] Regardless of the specific design and function of landing sub 100 (which will be described in more detail below), once landed, first dart 60 sealingly engages with seat 102 (under the pressure exerted by mud 54) so that fluids (e.g., mud 54) may not pass between dart 60 and seat 102. As will be described in more detail below, the landing and sealing engagement of first dart 60 on seat 102 (in addition to potentially causing deployment of seat 104) may further actuate landing sub 100 to open one or more alternative flow paths (not directly shown in Figure 4) that allow cement 54 to bypass dart 60 and seat 102 and flow out of casing (e.g., at or proximate terminal end 26) into annulus 13.

[0034] Referring now to Figures 4 and 5, after first dart 60 is landed on seat 102 as previously described, continued pumping of displacement fluid 56 causes advancement of second dart 62 downhole within casing 20 until second dart 62 lands on and sealingly engages with second seat 104. This advancement of second dart 62 after first dart 60 has landed on seat 102 forces most (or all) of the remaining mud 54 disposed between darts 60, 62 to flow through the bypass flow path around dart 60 and seat 102 and enter into annulus 13. As the mud 54 is flowed into annulus 13 it displaces fluids 52 out of annulus 13 and into annulus 15 (and finally to surface 5). As a result, in this embodiment, once second dart 62 is landed on seat 104, the entire annulus 13 is filled with cement 54, which will eventually dry and cure to provide the benefits and functions previously described above for lateral section 24 of casing 20. In addition to providing a fluid barrier between cement 54 and displacement fluid 56, second dart 62 may also provide feedback to the operators of the wellbore 16 (e.g., such as a change in pressure or flow rate within the casing 20 when second dart has landed against seat 104) that indicates when all (or substantially all) of the cement 54 has been displace into annulus 13 (so that further pumping of fluid 56 within casing 20 may cease).

[0035] Specific embodiments of landing sub 100 will now be described. It should be appreciated that any of the following embodiments of landing sub 100 may be used in the cementing operations shown in Figures 2-5.

[0036] Referring now to Figure 6, an embodiment of a landing sub or assembly 200 for use within a wellbore tubular string (e.g., casing string 20) is shown. Landing sub 200 includes a central or longitudinal axis 205, a first or uphole end 200a, and a second or downhole end 200b opposite uphole end 200a. In addition, landing sub 200 includes an outer housing 202 and a central landing assembly 220 disposed within the outer housing assembly 202. [0037] Outer housing assembly 202 comprises an uphole connector member 210, a downhole connector member 290, an uphole outer housing member 222, and a downhole outer housing member 470. Uphole connector member 210 includes a first or uphole end 210a, a second or downhole end 210b opposite uphole end 210a, a radially outer surface 210c extending between ends 210a, 210b, and a radially inner surface 21 Od also extending between ends 210a, 210b. Uphole end 210a is commensurate with uphole end 200a of landing sub 200. Radially inner surface 21 Od defines a throughbore 212 extending axially between ends 210a, 210b and includes a first or uphole connector 214 proximate uphole end 210a. In this embodiment, uphole connector 214 is a box-end threaded connector that is configured to threadably engage with a pin-end threaded connector disposed on a downhole end of the uphole adjacent tubular member forming the tubular string (e.g., casing 20). Radially outer surface 210c includes an external threaded connector 216 that is configured to threadably engage with a corresponding threaded connector disposed on central landing assembly 220 as will be described in more detail below.

[0038] Downhole connector member 290 includes a first or uphole end 290a, a second or downhole end 290b opposite uphole end 290a, a radially outer surface 290c extending between ends 290a, 290b, and a radially inner surface 290d also extending between ends 290a, 290b. Downhole end 290b is commensurate with downhole end 200b of landing sub 200. Radially outer surface 290c includes an uphole, external threaded connector 292 proximate uphole end 290a. Radially inner surface 290d defines a throughbore 291 extending between ends 290a, 290b, and includes a first cylindrical surface 294 extending from uphole end 290a, a radially extending shoulder 295 extending from first cylindrical surface 294, and a second cylindrical surface 296 extending axially from radially extending shoulder 295. Radially outer surface 290c includes a downhole connector 298 proximate downhole end 290b. In this embodiment downhole connector 298 is a pin-end threaded connector that is configured to threadably engage with a box-end threaded connector disposed on an uphole end of the downhole adjacent tubular member forming the tubular string (e.g., casing 20).

[0039] Uphole outer housing member 222 includes a first or uphole end 222a, a second or downhole end 222b opposite uphole end 222a, a radially outer surface 222c extending between ends 222a, 222b, and a radially inner surface 222d also extending between ends 222a, 222b. Radially outer surface 222c includes an external threaded connector 234 that is disposed between ends 222a, 222b. Radially inner surface 222d includes an internal threaded connector 224 proximate uphole end 222a, a first or uphole cylindrical surface 226, a second or central cylindrical surface 230 disposed downhole from uphole cylindrical surface 226, and a third or downhole cylindrical surface 232 disposed downhole from uphole cylindrical surface 226 and central cylindrical surface 230. In addition, radially inner surface 222d also includes an uphole facing frustoconical surface 230 extending between uphole cylindrical surface 226 and central cylindrical surface 230, and a radially extending shoulder 233 extending between central cylindrical surface 230 and downhole cylindrical surface 232. Uphole cylindrical surface 226 includes a larger inner diameter than central cylindrical surface 230, and thus, frustoconical surface 226 extends radially inward when moving from uphole cylindrical surface 226 to central cylindrical surface 230. Further, central cylindrical surface 228 has a smaller inner diameter than downhole cylindrical surface 232 and thus, radially extending shoulder 233 extends radially outward from central cylindrical surface 228 to downhole cylindrical surface 232.

[0040] Downhole outer housing member 270 includes a first or uphole end 270a, a second or downhole end 270b opposite uphole end 270a, a radially outer surface 270c extending between ends 270a, 270b, and a radially inner surface 270d also extending between ends 270a, 270b. Radially inner surface 270d includes a first or uphole internal threaded connector 272 at uphole end 270a and a second or downhole internal threaded connector 274 at downhole end 270b.

[0041] As shown in Figure 6, connector 224 on uphole outer housing member 222 is threadably engaged with connector 216 on uphole connector member 210. In addition, connector 272 on downhole outer housing member 270 is threadably engaged with connector 234 on uphole outer housing member 222. Further, connector 274 on downhole outer housing member 270 is threadbaly engaged with connector 292 on downhole connector member 290. Therefore, each of the members 210, 222, 270, and 290 are threadably secured to one another and coaxially aligned along axis 205. [0042] Referring still to Figure 6, central landing assembly 220 includes a first or uphole landing sleeve 240, second or downhole landing sleeve 280, and a central sleeve 260 coupled to and extending between sleeves 240, 280. Uphole landing sleeve 240 includes a first or uphole end 240a, a second or downhole end 240b opposite uphole end 240a, a radially outer surface 240c extending between ends 240a, 240b, and a radially inner surface 240c also extending between ends 240a, 240b. Radially inner surface 240d defines a throughbore 252 extending axially between ends 240a, 240b. Radially outer surface 240c includes a first or uphole cylindrical surface 246 extending axially from uphole end 240a, a second or downhole cylindrical surface 248 extending axially from downhole end 240b, and a radially extending shoulder 250 extending radially between cylindrical surfaces 246, 248.

[0043] A plurality of apertures or ports 242 extend radially between uphole cylindrical surface 246 and radially inner surface 240d. Each of the ports 242 slidably receive an engagement member or dog 244 therethough. Referring briefly to Figure 7, each dog 244 includes a radially outer side 244a, a radially inner side 244b, and a shoulder 244c disposed radially between sides 244a, 244b. In addition, each port 242 includes an internal shoulder 242a disposed radially between uphole cylindrical surface 246 and radially inner surface 240d of sleeve 240. Referring now to Figures 6 and 7, each of the dogs 244 is transitionable or actuatable between a first or radially withdrawn position as shown in Figure 6 and a second or radially collapsed position shown in Figure 7. In particular, when dogs 244 are in the radially withdrawn position, shoulders 244c of dogs 244 are radially separate from shoulders 242a within ports 242 and radially inner sides 244b of dogs 244 are radially retracted or withdrawn from axis 205. When dogs 244 are in the radially collapsed position, shoulders 244c of dogs 244 are engaged with and abut with shoulders 242a and radially inner sides 244b of dogs 244 are radially collapsed in toward axis 205. It should be appreciated that in some embodiments, shoulders 244c, 242a may not engage when dogs 244 are in the radially collapsed position.

[0044] Referring back to Figure 6, a plurality of apertures or ports 254 extend radially from radially inner surface 240d to downhole cylindrical surface 248. As will be explained in more detail below, ports 254 provide communication to a bypass flow path for fluids during operation of landing sub 200.

[0045] Referring still to Figure 6, central connecting sleeve 260 (or more simply“central sleeve 260”) includes a first or uphole end 260a, a second end 260b opposite uphole end 260a, a radially outer surface 260c extending between ends 260a, 260b, and a radially inner surface 260d also extending between ends 260a, 260b. A plurality of apertures or ports 262 extend radially between surfaces 260c, 260d proximate uphole end 260a. In addition, radially inner surface 260d defines a throughbore 264 extending between ends 260a, 260b and includes an internal threaded connector 266 disposed proximate downhole end 260b.

[0046] Downhole landing sleeve 280 includes a first or uphole end 280a, a second or downhole end 280b opposite uphole end 280a, a radially outer surface 280c extending between ends 280a, 280b, and a radially inner surface 280d also extending between ends 280a, 280b. Radially outer surface 280c includes an external threaded connector

287 proximate uphole end 280a. In addition, radially inner surface 280d defines a throughbore 282 extending between ends 280a, 280b, and includes a landing surface

288 proximate uphole end 280a. A plurality of ports 286 extend radially through sleeve 280 from radially outer surface 280c to radially inner surface 280d axially downhole of landing surface 288.

[0047] As shown in Figure 6, downhole end 240b of uphole landing sleeve 240 is received into throughbore 264 of central sleeve 260 from uphole end 260a such that ports 254 in landing sleeve 240 are axially and circumferentially aligned with ports 262 in central sleeve 260. This initial relative axial and circumferential position of uphole landing sleeve 240 and connecting sleeve 260 is maintained with a plurality of evenly circumferentially spaced shear pins 256 that extend radially between sleeves 240, 260. In addition, as is also shown in Figure 6, uphole end 280a of downhole landing sleeve 280 is received within throughbore 264 of central sleeve 260 so that connector 266 on connecting sleeve 260 is threadably engaged with connector 287 on landing sleeve 280.

[0048] Moreover, still referring to Figure 6, the coupled sleeves 240, 260, and 280 are all coaxially disposed within the coupled outer housing members 222 and 270 along axis 205, and are axially positioned between uphole connecting member 210 and downhole connecting member 290. In addition, when sleeves 240, 260, 280 are received within outer housing members 222, 270 as previously described, an annulus or annular region 221 is formed axially between downhole end 222b of uphole outer housing member 222 and uphole end 290a of downhole connecting member 290 that extends radially between outer housing 202 and central landing assembly 220. In particular, the annulus 221 extends radially between the radially outer surfaces 260c, 280c of sleeves 260, 280, respectively, and radially inner surface 270d of downhole outer housing member 270. Initially, sleeves 240, 260, 280 are installed within outer housing members 222, 270 such that the aligned ports 254, 262 of sleeves 240, 260, respectively are axially overlapped with downhole cylindrical surface 230 within uphole outer housing member 222 so that fluid communication between throughbore 252 of sleeve 240 and annulus 221 is prevented (or at least restricted).

[0049] Referring now to Figures 6 and 8, during operations, landing sub 200 is coupled to and coaxially aligned with casing 20 (see Figure 1 ) via connectors 214, 298 as previously described, and first dart 60 is flowed axially through throughbores 212, 252, 624 of connecting member 210 and sleeves 240, 260 until a head 70 of first dart 60 lands and engages on landing surface 288 within downhole landing sleeve 280. As will be described in more detail below, the landing of first dart 60 upon landing surface 288 causes central landing assembly 220 to transition or actuate from a first or initial position shown in Figure 6 to a second position shown in Figure 8.

[0050] In particular, dart 60 includes a plurality of skirts or sealing members 72 that are coupled to head and axially spaced from one another along axis 205. Each of the skirts 72 sealingly engages with radially inner surface 260d of central sleeve 260 when head 70 of dart 60 is engaged with landing surface 288. As a result, fluid (e.g., cement 54 in Figures 2-5) is prevented (or at least restricted) from flowing through throughbore 264 of central sleeve 260 and into and past throughbore 282 of downhole landing sleeve 280, so that an axial load is placed on sleeves 240, 260, 280 via dart 60. Eventually, this axial load causes shear pins 283 extending between downhole connecting member 290 and downhole landing sleeve 280 to fail such that sleeves 240, 260, 280 transition axially within outer housing members 222, 270 from the first position of Figure 6 to the second position of Figure 8 where downhole end 280b of lower landing sleeve 280 is engaged with radially extending shoulder 295 within lower connecting member 290 and the aligned ports 254, 262 of sleeves 240, 260, respectively are now axially aligned with a portion of annulus 221. Accordingly, when central landing assembly 220 actuates to the second position of Figure 8, a bypass flow path is established that allows the fluid uphole of first dart 60 (e.g., cement 54 shown in Figures 2-5) to flow around landed dart 60 within landing sub 200. In particular, the bypass flow path extends from throughbore 252 of sleeve 240, through ports 254, 262, into annulus 221 , and back into throughbore 282 of sleeve 280 downhole of head 70 of first dart 60.

[0051] Referring now to Figures 6-9, when central landing assembly 220 (e.g., sleeves 240, 260, 280) are axially transitioned from the first position of Figure 6 to the second position of Figure 8, the dogs 244 are transitioned or actuated from the radially withdrawn position of Figure 6 to the radially collapsed position of Figures 7 and 8 to thereby deploy a second or uphole landing surface 249 defined by the radially inner sides 244b of dogs 244. In particular, axial translation of sleeves 240, 260, 280 within outer housing 202 causes the radially outer sides 244b of dogs 244 to slidingly engage with radially inner surface 222d of uphole outer housing member 222 so that dogs 244 slide from uphole cylindrical surface 226, past frustoconical surface 228, and finally onto downhole cylindrical surface 230. Because downhole cylindrical surface 230 has a smaller inner diameter than uphole cylindrical surface 226, the sliding engagement of dogs 244 along surfaces 226, 228, 230 as sleeves 240, 260, 280 axially transition from the first position of Figure 6 to the second position of Figure 8 causes dogs 244 to actuate radially inward from their initial radially retracted position with radially inner sides 244b radially withdrawn away from axis 205 to the radially collapsed position with radially inner sides 244b collapsed radially inward toward axis 205 as previously described above (see Figure 7). Thus, transitioning sleeves 240, 260, 280 to the second position shown in Figure 8 actuates or deploys the uphole landing surface 249 (see Figures 7 and 9) within central landing assembly 220.

[0052] Thereafter, when second dart 62 (which includes a head 70 and skirts 72 like the first dart 60) is flowed through throughbore 212 of uphole connecting member 210 and into throughbore 252 of uphole landing sleeve 240, the head 70 of second dart 62 lands and engages with uphole landing surface 249 (which is defined by dogs 244 as previously described) so that further axial advancement of second dart 62 is prevented. In addition, when head 70 of second dart 62 is landed on surface 249 the skirts 72 of dart 62 sealingly engage with radially inner surface 21 Od of uphole connector member 210 so that fluids (e.g., displacement fluid 56 in Figures 2-5) are prevented from flowing through throughbore 212 of member 210 and an axial load is placed on uphole landing sleeve 240 via dart 62. Eventually, this axial load causes shear pins 256 extending between uphole landing sleeve 240 and connecting sleeve 260 to fail so that central landing assembly 220 is transitioned or actuated from the second position of Figure 8 to a third position of Figure 9. In particular, upon failure of shear pins 256 under the axial load imposed by second dart 62, uphole landing sleeve 240 is transitioned axially downhole within connecting sleeve 260 until radial shoulder 250 on uphole landing sleeve 240 engages with uphole end 260a of connecting sleeve 260. This axial downhole movement of uphole landing sleeve 240 within connecting sleeve 260 to transition the central landing assembly 220 to the third position of Figure 9 also axially misaligns ports 254, 262 so that the fluid communication between throughbore 252 of sleeve 240 and annulus 221 via ports 254, 262 is once again prevented and bypass flow path flowing through annulus 221 is closed.

[0053] Referring now to Figure 10, an embodiment of a landing sub or assembly 300 for use within a wellbore tubular string (e.g., casing string 20) is shown. Landing sub 300 includes many of the same features as landing sub 200 of Figures 6-9, and thus, in the following description, like features are identified with the same reference numerals, and the discussion below will focus on the features of landing sub 300 that are different from landing sub 200. In particular, landing sub 300 includes a central or longitudinal axis 305, a first or uphole end 300a, and a second or downhole end 300b opposite uphole end 300a. In addition, landing sub 300 includes an outer housing 302 and a central landing assembly 320 disposed within the outer housing 302. .

[0054] Outer housing 302 includes an uphole connector member 310, downhole connector member 290, uphole outer housing member 222, and downhole outer housing member 270. Each of the downhole connector member 290, uphole outer housing member 222, and downhole outer housing member 270 are the same as previously described above for landing sub 200.

[0055] Downhole connector 290 is the same as previously described above for landing sub 200. Uphole connector member 310 includes a first or uphole end 310a, a second or downhole end 310b opposite uphole end 310a, a radially outer surface 310c extending between ends 310a, 310b, and a radially inner surface 31 Od also extending between ends 310a, 310b. Uphole end 310a is commensurate with uphole end 300a of landing sub 300. Radially inner surface 31 Od defines a throughbore 312 extending axially between ends 310a, 310b, and includes a first or uphole connector 314 proximate to uphole end 310a. In this embodiment, uphole connector 314 is a box-end threaded connector that is configured to threadably engage with a pin-end threaded connector disposed on a downhole end of the uphole adjacent tubular member forming the tubular string (e.g., casing 20). Radially outer surface 310c includes an external connector 316, and a downward facing frustoconical surface 318 extending axially uphole from downhole end 310b. As will be described in more detail below, external connector 316 is configured to threadably engage with a corresponding threaded connector disposed on central landing assembly 320.

[0056] Referring still to Figure 10, central landing assembly 320 includes a first or uphole landing sleeve 340, downhole landing sleeve 280, and central sleeve 260 coupled to and extending between the uphole landing sleeve 340 and downhole landing sleeve 280. Each of the downhole landing sleeve 280 and central sleeve 260 are the same as previously described above for landing sub 200.

[0057] Uphole landing sleeve 340 includes a first or uphole end 340a, a second or downhole end 340b opposite uphole end 340a, a radially outer surface 340c extending between ends 340a, 340b, and a radially inner surface 340c also extending between ends 340a, 340b. Radially inner surface 340d defines a throughbore 352 extending axially between ends 340a, 340b. Radially outer surface 340c includes a cylindrical surface 348 extending axially from downhole end 340b, and a radially extending shoulder 350 extending radially from cylindrical surface 248.

[0058] A plurality of axially extending slots 342 extending axially from uphole end 340a and radially between surfaces 340c, 340d. Therefore, slots 342 define a plurality of engagement members 344. In this embodiment, the engagement members 344 comprise a plurality of axially extending collets 344 that are evenly circumferentially spaced about axis 305. Each collet 344 includes a first or free end 344a that is commensurate with uphole end 340a of landing sleeve 340, and a second or fixed end 344b opposite free end 344a. In addition, each collet 344 includes a radially outer engagement surface 347 and an uphole facing frustoconical surface 346 each extending axially from free end 344a. Further, each collet 344 includes a radially inner engagement surface 349 extending axially from frustoconical surface 346. It should be appreciated that outer engagement surfaces 347 form a portion of radially outer surface 340c and that frustoconical surfaces 346 and inner engagement surfaces 349 form a portion of radially inner surface 340d. When landing sub 300 is in a first position as shown in Figure 10, frustoconical surfaces 346 are each engaged with frustoconical surface 318 of uphole connector member 310 such that collets 344 are forced radially outward or radially away from axis 305 to a radially expanded or withdrawn position. As will be explained in more detail below, when frustoconical surfaces 346 on collets 344 disengage from frustoconical surface 318, collets 344 are free to move radially inward or toward axis 305 toward a radially collapsed position, such that engagement surfaces 349 together form a second or uphole landing surface 343 within sleeve 340.

[0059] A plurality of apertures or ports 354 extend radially from radially inner surface 340d to cylindrical surface 348. As will be explained in more detail below, ports 254 align with ports 262 in central sleeve 260 to provide selective communication to a bypass flow path for fluids during operation of landing sub 300.

[0060] As shown in Figure 10, downhole end 340b of uphole landing sleeve 340 is received within throughbore 264 of connecting sleeve 260 from uphole end 260a such that ports 354 in landing sleeve 340 are axially and circumferentially aligned with ports 262 in central sleeve 260. This initial relative axial and circumferential position of uphole landing sleeve 340 within central sleeve 260 is maintained with a plurality of evenly circumferentially spaced shear pins 256 extending radially between sleeves 340, 360. In addition, downhole landing sleeve 280 and connecting sleeve 260 are coupled together via threaded connectors 287, 266 in the same manner as described above for landing sub 200. [0061] Moreover, the coupled sleeves 340, 260, and 280 are all coaxially disposed within outer housing members 222 and 270 along axis 305, and axially positioned between connecting members 210 and 290, such that annulus 221 is formed in the same manner as previously described for landing sub 200. Initially, sleeves 340, 260, 280 are installed within outer housing members 222, 270 such that the aligned ports 354, 262 of sleeves 240, 260, respectively, are axially overlapped with downhole cylindrical surface 230 within uphole outer housing member 222, so that fluid communication between throughbore 352 of sleeve 340 and annulus 221 is prevented (or at least restricted).

[0062] Referring now to Figures 10 and 11 , during operations landing sub 300 is coupled to and coaxially aligned with casing 20 (see Figure 1 ) via connectors 314, 298 as previously described, and first dart 60 is flowed axially through throughbores 312, 352, 264 of connecting member 210 and sleeves 240, 260 until a head 70 of first dart 60 lands and engages on landing surface 288 within downhole landing sleeve 280. As will be described in more detail below, the landing of first dart 60 upon landing surface 288 causes central landing assembly 320 to transition or actuate from a first or initial position shown in Figure 10 to a second position shown in Figure 11.

[0063] In particular, skirts 72 of dart 60 sealingly engage radially inner surface 260d of sleeve 260 when head 70 of dart 60 is engaged with landing surface 288. As a result, fluid (e.g., cement 54 in Figures 2-5) is prevented (or at least restricted) from flowing through throughbore 264 of central sleeve 260 and into and past throughbore 282 of downhole landing sleeve 280, so that an axial load is placed on sleeves 340, 260, 280 via dart 60. Eventually, this axial load causes shear pins 283 extending between downhole connecting member 290 and downhole landing sleeve 280 to fail such that sleeves 340, 260, 280 transition axially within outer housing members 222, 270 from the first position of Figure 10 to the second position of Figure 11 where downhole end 280b of lower landing sleeve 280 is engaged with radially extending shoulder 295 within lower connecting member 290 and the aligned ports 354, 262 of sleeves 240, 260, respectively are now axially aligned with a portion of annulus 221. Accordingly, when central landing assembly 320 actuates to the second position of Figure 8, a bypass flow path is established that allows the fluid uphole of first dart 60 (e.g., cement 54 shown in Figures 2-5) to flow around the landed dart 60 within landing sub 300. In particular, the bypass flow path extends from throughbore 352 of sleeve 340, through ports 354, 262, into annulus 221 , and back into throughbore 282 of sleeve 280 via ports 286 downhole of first dart 60.

[0064] Referring now to Figures 10-12, when central landing assembly 320 (e.g., sleeves 340, 260, 280) are axially transitioned from the first position of Figure 10 to the second position of Figure 11 , the collets 344 are transitioned or actuated from the radially withdrawn position of Figure 10 to the radially collapsed position of Figure 11 to thereby deploy the second or uphole landing surface 343 defined by engagement surface 349 of collets 344. In particular, axial translation of sleeve 340, 260, 280 within outer housing 302 causes frustoconical surfaces 346 of collets 344 to disengage from frustoconical surface 318 on uphole connecting member 310. As a result, collets 344 are free to move radially inward to the radially collapsed position (i.e. , toward axis 305) such that radially inner surfaces 349 of collets 344 circumferential align to define landing surface 343 (see Figure 12). The radially inward transition of collets 344 is also facilitated by sliding engagement of radially outer surfaces 347 on collets 344 with cylindrical surface 226, frustoconical surface 228, and cylindrical surface 230 within uphole outer housing member 222. In particular, because downhole cylindrical surface 230 has a smaller inner diameter than uphole cylindrical surface 226, the sliding engagement of radially outer surfaces 347 of collets 344 along surfaces 226, 228, 230 forces collets 344 radially inward toward axis 305 toward the radially collapsed position to form landing surface 343 as previously described. In some embodiments, collets 244 are radially biased toward the radially collapsed position shown in Figure 11. Thus, transitioning sleeves 340, 260, 280 to the second position of Figure 11 also actuates or deploys uphole landing surface 343 within central landing assembly 320.

[0065] Thereafter, as shown in Figure 12, when second dart 62 is flowed through throughbore 312 of uphole connecting member 310 and into throughbore 352 of uphole landing sleeve 340, head 70 of second dart 62 lands and engages with uphole landing surface 343 (which is defined by collets 344 as previously described) so that further axial advancement of second dart 62 is prevented. In addition, when head 70 of second dart 62 is landed on surface 343, skirts 72 of dart 62 sealingly engage with radially inner surface 31 Od of uphole connector member 310 so that fluids (e.g., displacement fluid 56 in Figures 2-5) are prevented from flowing through throughbore 312 of member 310 and an axial load is placed on uphole of landing sleeve 340 via dart 62. Eventually, this axial load causes shear pins 256 extending between sleeves 340, 260 to fail, so that central landing assembly 320 is transitioned or actuated from the second position of Figure 1 1 to a third position of Figure 12. In particular upon failure of share pins 256 under the axial load imposed by second dart 62, uphole landing sleeve 340 is transitioned axially downhole within connecting sleeve 260 until radial shoulder 350 engages with uphole end 260a of connecting sleeve 260. This axial downhole movement of uphole landing sleeve 340 within connecting sleeve 260 to transition the central landing assembly 320 to the third position of Figure 12 also axially misaligns ports 354, 262 so that the fluid communication between throughbore 352 of sleeve 340 and annulus 221 via ports 254, 262 is once again prevented and the bypass flow path defined by annulus 221 is closed.

[0066] In the manner described, each of the landing subs 200, 300 shown in Figures 6 and 10 are configured such that the landing of a first dart (e.g., dart 60) on a first or downhole landing surface (e.g., landing surface 288) actuates a central landing assembly (e.g., central landing assemblies 220, 320) from a first position to a second position to deploy a second or uphole landing surface (e.g., landing surfaces 249, 343) and to open a bypass flow path that routes fluids around the landed first dart. In addition, central landing assemblies (e.g., assemblies 220, 320) of the disclosed landing subs (e.g., subs 200, 300) are further configured to transition from the second position to a third position to close of the bypass flow path upon landing a second dart (e.g., dart 62) on the second landing surface.

[0067] Because the second or uphole landing surface (e.g., landing surfaces 249, 343) of the previously described landing subs (e.g., subs 200, 300) are deployable, each of the first and second darts (e.g., darts 60, 62) of the cementing operation may be the same size. This simplifies the use of multiple darts or other suitable flowable valve members during a cementing operation like the one described above (e.g., see Figures 2-5). For example, the size of both darts 60, 62 may be chosen to be large enough so that the central landing assemblies (e.g., central landing assemblies 202, 302) of the disclosed subs (e.g., subs 200, 300) are actuated between the first, second, and third position as previous described, but also small enough so that other landing assemblies within casing 20 disposed uphole of the landing sub (e.g., subs 200, 300), such as those installed within casing 20 to facilitate a subsequent hydraulic fracturing operations, do not prevent axial progress of the darts 60, 62 during the cementing operation. However, in spite of these benefits, it should be appreciated that in other embodiments, the uphole and downhole landing surfaces for the darts (e.g., darts 60, 62) may be sized so that the first and second darts may be different sizes.

[0068] For example, reference is now made to Figure 13, which shows another embodiment of a landing sub or assembly 400 for use within a wellbore tubular string (e.g., casing string 20). Landing sub 400 includes a central or longitudinal axis 405, a first or uphole end 400a, and a second or downhole end 400b opposite uphole end 400a. In addition, landing sub 400 also includes an outer housing 402 and a central landing assembly 420 disposed within housing 402.

[0069] Outer housing 402 includes a first or uphole connector member 410, a second or downhole connector member 490, and an outer housing member 470 coupled to and extending axially between connector members 410, 490. Referring still to Figure 13, uphole connector member 410 includes a first or uphole end 410a, a second or downhole end 410b opposite uphole end 410a, a radially outer surface 410c extending between ends 410a, 410b, and a radially inner surface 41 Od also extending between ends 410a, 410b. Uphole end 410a is commensurate with uphole end 400a of landing sub 400. Radially inner surface 41 Od defines a throughbore 412 extending between ends 410a, 410b, and includes a first or uphole internal threaded connector 414 proximate uphole end 410a, a second or downhole internal threaded connector 418 disposed between ends 410a, 410b, and a radially extending shoulder 419. In this embodiment, uphole connector 414 is a box-end threaded connector that is configured to threadably engage with a pin-end threaded connector disposed on a downhole end of the uphole adjacent tubular member forming the tubular string (e.g., casing 20). Radially outer surface 410c includes an external threaded connector 216 that is threadably engaged with a corresponding threaded connector disposed on central outer housing member 470 as will be described in more detail below. [0070] Central outer housing member 470 includes a first or uphole end 470a, and a second or downhole end 470b opposite uphole end 470a. In addition, housing member 470 includes a radially outer surface 470c extending between ends 470a, 470b, and a radially inner surface 470d also extending between ends 470a, 470b. Radially inner surface 470d defines throughbore 476 extending between ends 470a, 470b and includes a first or uphole threaded connector 472 proximate uphole end 470a, and a second or downhole threaded connector 474 proximate downhole end 470b. Uphole connector 474 is threadably engaged with external threaded connector 416 on radially outer surface 410c of uphole connector member 410.

[0071] Downhole connector member 490 includes a first or uphole end 490a, a second or downhole end 490b opposite uphole end 490a, a radially outer surface 490c extending between ends 490a, 490b, and a radially inner surface 490d also extending between ends 490a, 490b. Downhole end 490b is commensurate with downhole end 400b of landing sub 400. Radially outer surface 490c includes a downhole threaded connector 498. In this embodiment downhole threaded connector 498 is a pin-end threaded connector that is configured to threadably engage with a box-end threaded connector disposed on an uphole end of the downhole adjacent tubular member forming the tubular string (e.g., casing 20). In addition, radially outer surface 490c also includes an uphole threaded connector 492. Uphole connector 492 is threadably engaged with downhole connector 474 on outer housing member 470. Therefore, each of the uphole connector member 410, outer housing member 470, and downhole connector member 490 are coaxially aligned along axis 405.

[0072] Referring still to Figure 13, central landing assembly 420 includes a first or uphole landing sleeve 440, a second or downhole landing sleeve 480, and a central connecting sleeve 460 (or more simply “central sleeve 460”) coupled to downhole landing sleeve 480 and disposed axially between uphole landing sleeves 440 and 480. Uphole landing sleeve 440 is a tubular member that includes a first or uphole end 440a, a second or downhole end 440b opposite uphole end 440a, a radially outer surface 440c extending between ends 440a, 440b, and a radially inner surface 440d also extending between ends 440a, 440b. Radially outer surface 440c includes a threaded connector 442. Radially inner surface 440d defines a throughbore 446 extending between ends 480a, 480b and includes an uphole landing surface 444 proximate uphole end 440a. Uphole landing sleeve 440 is coaxially received within throughbore 412 of uphole connector member 410 such that connector 442 is threadably engaged with internal connector 418 until downhole end 440b engages with shoulder 419.

[0073] Central sleeve 460 is a tubular member that includes a first or uphole end 460a, a second or downhole end 460b opposite uphole end 460a, a radially outer surface 460c extending between ends 460a, 460b, and a radially inner surface 460d also extending between ends 460a, 460b. A plurality of apertures or ports 462 extend radially between radially outer surface 460c and radially inner surface 460d that are axially disposed more proximate uphole end 460a than downhole end 460b. In addition, radially inner surface 460d defines a throughbore 468 extending between ends 460a, 460b and includes a threaded connector 464 proximate downhole end 460b. Central sleeve 460 is initially coaxially installed within outer housing member 470 such that uphole end 460a engages or abuts with downhole end 440b of uphole landing sleeve 440 and so that ports 462 are axially overlapped with radially inner surface 41 Od of uphole connector member 410. This initial axial position of central sleeve 460 within uphole connector 410 is maintained with a plurality of evenly circumferentially spaced shear pins 466 extending radially between uphole connector member 410 and central sleeve 460.

[0074] Downhole landing sleeve 480 includes a first or uphole end 480a, a second or downhole end 480b opposite uphole end 480a, a radially outer surface 480c extending between ends 480a, 480b, and a radially inner surface 480d also extending between ends 480a, 480b. Radially outer surface 480c includes an external threaded connector 488 proximate uphole end 480a. In addition, radially inner surface 480d defines a throughbore 486 extending between ends 480a, 480b and includes a landing surface 482 proximate uphole end 480a. A plurality of ports 484 extend radially through sleeve 480 from radially outer surface 480c to radially inner surface 480d axially downhole of landing surface 482.

[0075] Downhole landing sleeve 480 is secured to central sleeve 460 by threadably engaging external connector 488 on downhole landing sleeve 480 with internal connector 464 on central sleeve 460. Thus, because central sleeve 460 is initially axially and circumferentially fixed within outer housing member 470 via shear pins 466, lower landing sleeve 480 also has an initial axial and circumferential position within outer housing member 470 due to the threaded engagement at connectors 464, 488. In addition, when sleeves 460 480 are coaxially received within throughbore 476 of outer housing member 470, an annulus or annular region 421 is formed radially between outer housing 402 and central landing assembly 420. In particular, annulus 421 extends axially between downhole end 410b of uphole connecting member 410 and uphole end 490a of downhole connecting member 490 and radially between the radially outer surfaces 460c, 480c of sleeves 460, 480, respectively, and radially inner surface 470d of outer housing member 470. Initially, when sleeves 460 is received within throughbore 412 of uphole connector member 410 as shown in Figure 13, ports 462 are axially overlapped with radially inner surface 41 Od so that fluid communication between annulus 421 and throughbore 468 of sleeve 460 through ports 462 is prevented (or at least restricted).

[0076] Referring now to Figures 13 and 14, during operations landing sub 400 is coupled to and coaxially aligned with casing 20 (see Figure 1 ) via connectors 414, 498 as previously described, and a first dart 80 (which includes head 70 and skirts 72 as previously described for darts 60, 62) is flowed axially through throughbores 412, 446, 468 of connecting member 410 and sleeves 440, 460 until head 70 lands and engages on landing surface 482 within throughbore 486 of downhole landing sleeve 480. Landing surface 444 in uphole landing sleeve 440 has a larger inner diameter than landing surface 482 in downhole landing sleeve 480 such that head 70 of first dart 80 advances axially past landing surface 444 and eventually engages with landing surface 482 in downhole landing sleeve 480 as previously described. As will be described in more detail below, the landing of first dart 80 upon landing surface 482 causes central landing assembly 420 to transition or actuate from a first or initial position shown in Figure 13 to a second position shown in Figure 14.

[0077] In particular, when head 70 of first dart 80 is engaged with landing surface 482 as previously described, skirts 72 of dart 80 sealingly engage radially inner surface 460d within throughbore 468 of sleeve 460. As a result, fluid (e.g., cement 54 in Figures 2-5) is prevented (or at least restricted) from flowing through throughbore 468 of central sleeve 460 and into and past throughbore 486 of downhole landing sleeve 480, so that an axial load is placed on sleeves 460, 480 via dart 80. Eventually this axial load causes shear pins 466 extending between uphole connecting member 410 and central sleeve 460 to fail such that sleeves 460, 480 transition axially within outer housing member 470 from the first (or initial) position of Figure 13 to the second position of Figure 14 where downhole end 480b of lower landing sleeve 480 is engaged with uphole end 490a of downhole connecting member 490, and ports 462 are axially aligned with a portion of annulus 421. Accordingly, when central landing assembly 420 actuates to the second position of Figure 14, a bypass flow path is established that allows the fluid uphole of first dart 80 (e.g., cement 54 shown in Figures 2-5) to flow around landed dart 80 within landing sub 400. In particular, the bypass flow path extends from throughbore 468 of sleeve 460, through ports 462, into annulus 421 , and back into throughbore 486 of sleeve 480 via ports 484 downhole of head 70 of first dart 80.

[0078] Referring now to Figures 13-15, after first dart 80 has landed within downhole landing sleeve 480 on landing surface 482 as described above, a second dart 82 (which includes a head 70 and skirts 72 as previously described for darts 60, 62) is flowed through throughbore 412 of uphole connecting member 410 and into throughbore 446 of uphole landing sleeve 440. In this embodiment, second dart 82 has a larger outer diameter than first dart 80 (e.g., head 70 of second dart 82 has a larger outer diameter than head 70 of first dart 80). As a result, when dart 82 enters throughbore 446 of uphole landing sleeve 440, head 70 of second dart 80 engages with landing surface 444 and skirts 72 sealingly engage with radially inner surface 41 Od of uphole connector member 410. Accordingly, after second dart 82 has landed within uphole landing sleeve 440, fluid flow through throughbore 446 is prevented (or at least restricted) such that the bypass flow path formed by throughbore 468, ports 462, annulus 421 , and throughbore 486 is closed (or at least restricted).

[0079] Some embodiments of a landing sub disclosed herein (e.g., landing sub 100) may also include or incorporate burst discs or other pressure actuated assemblies for selectively relieving pressure to the annulus between the casing pipe and the wellbore wall (e.g., annulus 19 outside of casing 20 in Figure 1 ) to provide an alternative flow path for fluids (e.g., cement 54) if the annular flow paths defined within the landing sub become blocked or clogged. For example, referring now to Figure 16, an embodiment of a landing sub or assembly 500 for use within a wellbore tubular string (e.g., casing string 20) is shown. Landing sub 500 includes many similar features as landing sub 400 (previously described), and thus, in the following description, like features are identified with like reference numerals, and the discussion below will focus on the features of landing sub 500 that are different from landing sub 400. In particular, landing sub 500 includes a central or longitudinal axis 505, a first or uphole end 500a, and a second or downhole end 500b opposite uphole end 500a. In addition, landing sub 500 includes an outer housing 502 and a central landing assembly 520 disposed within the outer housing 502.

[0080] Outer housing 502 includes a first or uphole connecting member 510, downhole connector 490, a first or uphole outer housing member 544, and outer housing member 470. Outer housing member 470 and downhole connecting member 490 are the same as previously described above for landing sub 400.

[0081] Uphole connector member 510 includes a first or uphole end 510a, a second or downhole end 510b opposite uphole end 510a, a radially outer surface 510c extending between ends 510a, 510b, and a radially inner surface 51 Od also extending between ends 510a, 510b. Uphole end 510a is commensurate with uphole end 500a of landing sub 500. Radially inner surface 51 Od defines a throughbore 512 extending between ends 510a, 510b, and includes an uphole internal threaded connector 614 proximate uphole end 510a, a radially extending shoulder 519, and a downhole internal threaded connector 516 extending from downhole end 510b. In this embodiment, uphole internal connector 514 is a box-end threaded connector that is configured to threadably engage with a pin-end threaded connector disposed on a downhole end of the uphole adjacent tubular member forming the tubular string (e.g., casing 20). In addition, in this embodiment, downhole internal connector 516 is threadably engaged with an external connector uphole outer housing member 522 in the manner described in more detail below.

[0082] Uphole outer housing member 522 includes a first or uphole end 522a, a second or downhole end 522b opposite uphole end 522a, a radially outer surface 522c extending between ends 522a, 522b, and a radially inner surface 522d also extending between ends 522a, 522b. Radially outer surface 522c includes a first or uphole threaded connector 524 proximate uphole end 522a, and a second or downhole threaded connector 526 proximate downhole end 522b. In addition, uphole outer housing member 522 includes a plurality of apertures or ports 527 extending radially from radially inner surface 522d to radially outer surface 522c. A burst disc 528 is installed within each of the ports 527 that is configured to fracture or fail when the pressure differential across ports 527 (i.e. , the pressure differential between the area outside of outer housing member 522 and the area within outer housing member 522) increases above a predetermined threshold.

[0083] As shown in Figure 16, uphole external connector 524 is threadably engaged with downhole internal connector 516 on uphole connector member 510, and downhole external connector 526 is threadably engaged with uphole internal connector 572 on outer housing member 470. In addition, outer housing member 470 is secured to lower connector member 490 in the same manner described above for landing sub 400. Therefore, each of the uphole connector member 510, uphole outer housing member 522, outer housing member 470, and downhole connector member 490 are coaxially aligned along axis 505.

[0084] Referring still to Figure 16, central landing assembly 520 includes a first or uphole landing sleeve 540, downhole landing sleeve 480, and a central connecting sleeve 560 disposed axially between landing sleeves 540, 480. Downhole landing sleeve 480 is the same as previously described above for landing sub 400.

[0085] Uphole landing sleeve 540 is a tubular member that includes a first or uphole end 540a, a second or downhole end 540b opposite uphole end 540a, a radially outer surface 540c extending between ends 540a, 540b, and a radially inner surface 540d also extending between ends 540a, 540b. Radially inner surface 540d defines a throughbore 542 that extends between ends 540a, 540b, and includes a landing surface 544 extending from uphole end 540a.

[0086] Central sleeve 560 is a tubular member that includes a first or uphole end 560a, a second or downhole end 560b opposite uphole end 560a, a radially outer surface 560c extending between ends 560a, 560b, and a radially inner surface 560d also extending between ends 560a, 560b. Radially inner surface 560d defines a throughbore 562 extending between ends 560a, 560b, and includes an internal threaded connector 564 disposed proximate downhole end 560b. In addition, central sleeve 560 includes a plurality of evenly circumferentially spaced apertures or ports 568 extending radially between radially inner surface 560d and radially outer surface 560c.

[0087] As shown in Figure 16, uphole landing sleeve 540 is disposed within uphole outer housing member 522 such that uphole end 540a of sleeve 540 is engaged with radially extending shoulder 519. This initial position of uphole landing sleeve 540 within uphole outer housing member 522 is maintained with a plurality of evenly circumferentially spaced shear pins 546 extending radially between uphole outer housing member 522 and uphole landing sleeve 540.

[0088] In addition, when uphole landing sleeve 540 is received within uphole outer housing member 522 as shown in Figure 16, an annulus or annular region 521 is formed radially between central landing assembly 520 and outer housing 502. In particular, annulus 521 extends axially between downhole end 522b of uphole outer housing member 522 and uphole end 490a of downhole connecting member 490 and radially between the radially outer surfaces 560c, 480c of sleeves 560, 480, respectively, and radially inner surface 470d of outer housing member 470. Further, as is also shown in Figure 16, when uphole end 560a of central sleeve 560 is received within uphole outer housing member 522 from downhole end 522b such that uphole end 560a engages with downhole end 540b of uphole landing sleeve 540, ports 568 are axially overlapped with radially inner surface 522d, and thus, fluid communication between throughbore 562 of sleeve 560 and annulus 521 through ports 568 is prevented (or at least restricted). This initial axial position of central sleeve 560 of within uphole outer housing member 522 is maintained with a plurality of evenly circumferentially spaced shear pins 567 extending radially between uphole outer housing member 522 and central sleeve 560. Still further, internal connector 544 is threadably engaged with external connector 488 on downhole landing sub 480. Therefore, each of the uphole landing sleeve 540, central sleeve 560, and downhole sleeve 480 are coaxially aligned within uphole outer housing member 522 and outer housing member 470 along axis 505. [0089] Referring now to Figures 16 and 17, during operations landing sub 500 is coupled to and axially aligned with casing 20 (see Figure 1 ) via connectors 514, 498 as previously described, and a first dart 80 (which includes head 70 and skirts 72 as previously described) is flowed axially through throughbores 512, 542, 562 of connecting member 510 and sleeves 540, 560 until head 70 lands and engages on landing surface 482 within throughbore 486 of downhole landing sleeve 480. Landing surface 544 in uphole landing sleeve 540 has a larger inner diameter than landing surface 482 in downhole landing sleeve 480 such that head 70 of first dart 80 advances axially past landing surface 544 and eventually engages with landing surface 482 in downhole landing sleeve 480 as previously described. As will be described in more detail below, the landing of first dart 80 upon landing surface 482 causes central landing assembly 520 to transition or actuate from a first or initial position shown in Figure 16 to a second position shown in Figure 17.

[0090] In particular, when head 70 of first dart 80 is engaged with landing surface 482 as previously described, skirts 72 of dart 80 sealingly engage with radially inner surface 560d within throughbore 562 of sleeve 560. As a result, fluids (e.g., cement 54 in Figures 2-5) is prevented (or at least restricted) from flowing through throughbore 562 of central sleeve 560 and into and past throughbore 486 of downhole landing sleeve 480, so that an axial load is placed on sleeves 560, 480 via dart 80. Eventually this axial load causes shear pins 567 extending between uphole outer housing member 522 and central sleeve 660 to fail such that sleeves 560, 480 transition axially within uphole outer housing member 522 and outer housing member 470 from the first position of Figure 16 to the second position of Figure 17 where downhole end 480b of lower landing sleeve 480 is engaged with uphole end 490a of downhole connecting member 490, and ports 568 are axially aligned with a portion of annulus 521. Accordingly, when central landing assembly 520 actuates to the second position of Figure 17, a bypass flow path is established that allows the fluid uphole of the first dart 80 (e.g., cement 54 shown in Figures 2-5) to flow around landed dart 80 within landing sub 500. In particular, the bypass flow path extends from throughbore 562 of sleeve 560, through ports 568, into annulus 521 , and back into throughbore 486 of sleeve 480 via ports 484 downhole of dart 80. [0091] In addition, when central landing assembly 520 actuates to the second position of Figure 17 (e.g., such that sleeves 560, 480 translate downhole toward downhole connecting member 490 as previously described), throughbore 542 of uphole landing sleeve 540 is placed in fluid communication with ports 527 and burst discs 528. As a result, if an overpressure of throughbore 542 should occur (i.e. , to result in a pressure differential across burst discs 528 that is above the predetermined threshold), burst discs 528 will fail, thereby allowing fluid (e.g., cement 54) to flow through ports 527 and outside of landing sub 500 (e.g., into annulus 19 shown in Figure 1 ). As previously described above, such an over pressuring of throughbore 542 may occur if there is a blockage within the bypass flow path defined by throughbore 562, ports 568, annulus 521 , and throughbore 486. Thus, burst discs 528 help to ensure that cement 54 is successfully advanced past (e.g., downhole of) landing sub 500 and into annulus 13 (see Figures 1 -5), even if there is a fluid blockage within landing sub 500.

[0092] Referring now to Figures 16-18, after first dart 80 has landed on landing surface 482 within downhole landing sleeve 480 as described above, a second dart 82 (which includes a head 70 and skirts 72 as previously described) is flowed through throughbore 512 of uphole connecting member 510 and into throughbore 542 of uphole landing sleeve 540. In this embodiment, second dart 82 has a larger outer diameter than first dart 80 as previously described above. As a result, when dart 82 enters throughbore 542 of uphole landing sleeve 540, head 70 of second dart 82 engages with landing surface 544 and skirts 72 (not specifically shown in Figure 20) sealingly engage with radially inner surface 51 Od of uphole connecting member 510. Accordingly, after second dart 82 has landed within uphole landing sleeve 540, fluid flow through throughbore 542 is prevented (or at least restricted) such that an axial load is placed on uphole landing sleeve 640 via dart 82 (note: the restriction of flow through throughbore 542 also prevents flow through bypass flow path partially formed by annulus 521 ). Eventually this axial load causes shear pins 546 to fail such that central landing assembly 520 is transitioned or actuated from the second position of Figure 17 to a third position shown in Figure 18. In particular, upon failure of shear pins 546 under the axial load imposed by second dart 82, uphole landing sleeve 540 translates axially downhole within uphole outer housing member 622 until downhole end 540b engages with uphole end 560a of central sleeve 560. This axial downhole movement of uphole landing sleeve 540 to transition the central landing assembly 520 to the third position of Figure 18 also causes ports 527 to be covered or axially overlapped by radially outer surface 540c of sleeve 540, such that fluid communication between throughbore 542 and ports 527 is closed.

[0093] In the manner described, the landing subs 400, 500 shown in Figures 13 and 16 are configured such that the landing of a first dart (e.g., dart 80) on a first or downhole landing surface (e.g., landing surface 482) actuates a central landing assembly (e.g., central landing assemblies 420, 520) from a first position to a second position to open a bypass flow path that routes fluids around the landed first dart. So that continued displacement of a second dart and fluid (e.g., cement) is possible following the landing of the first dart. In addition, central landing assemblies (e.g., assemblies 420, 520) of the disclosed landing subs (e.g., subs 400, 500) are further configured to close of the bypass flow path upon landing a second dart (e.g., dart 82) on a second landing surface.

[0094] Some embodiments of a landing sub disclosed herein (e.g., landing sub 100) may only be configured to land only a single dart on a landing surface during cementing operations (e.g., such as for cementing operations that only utilize a single flowable valve member). For example, referring now to Figure 19, an embodiment of a landing sub or assembly 600 for use within a wellbore tubular string (e.g., casing string 20) is shown. Landing sub 600 includes many similar features as landing sub 400 (previously described), and thus, in the following description, like features are identified with like reference numerals, and the discussion below will focus on the features of landing sub 600 that are different from landing sub 400. In particular, landing sub 600 includes a central or longitudinal axis 605, a first or uphole end 600a, and a second or downhole end 600b opposite uphole end 600a. In addition, landing sub 600 includes an outer housing 602 and a central landing assembly 620 disposed within outer housing 602.

[0095] Outer housing 602 includes a first or uphole connecting member 610, downhole connector 490, and a central outer housing member 470. Central landing assembly 620 includes landing sleeve 480 and a central sleeve 460. Each of the downhole connector 490, a outer housing member 470, landing sleeve 480, and central sleeve 460 are the same as previously described above for landing sub 400.

[0096] Uphole connector member 610 includes a first or uphole end 610a, a second or downhole end 610b opposite uphole end 610a, a radially outer surface 610c extending between ends 610a, 610b, and a radially inner surface 61 Od also extending between ends 610a, 610b. Uphole end 610a is commensurate with uphole end 600a of landing sub 600. Radially inner surface 61 Od defines a throughbore 612 extending between ends 510a, 510b, and includes an internal threaded connector 614 proximate uphole end 510a, and a radially extending shoulder 619. Radially outer surface 610c includes an external threaded connector 618 proximate downhole end 610b. In this embodiment, internal connector 614 is a box-end threaded connector that is configured to threadably engage with a pin-end threaded connector disposed on a downhole end of the uphole adjacent tubular member forming the tubular string (e.g., casing 20). In addition, external connector 618 is threadably engaged with internal connector 472 on outer housing member 470 such that uphole connector member is coaxially aligned with outer housing member 470 and downhole connecting member 490.

[0097] Initially, as shown in Figure 19, uphole end 460a of central sleeve 460 is received within throughbore 612 of connecting member 610 axially from downhole end 610b until uphole end 460a of sleeve 460 engages with radially extending shoulder 619. When in this initial position, ports 462 in sleeve 460 are axially overlapped with radially inner surface 61 Od of connecting member 610 so that fluid communication between annulus 421 and throughbore 468 of sleeve 460 through ports 462 is prevented (or at least restricted). This initial axial position of sleeves 460 (and thus also sleeve 480) and connector member 610 is maintained with a plurality of shear pins 667 extending radially through each of uphole connecting member 610 and central sleeve 460.

[0098] Referring now to Figures 19 and 20, during operations landing sub 600 is coupled to and coaxially aligned with casing 20 (see Figure 1 ) via connectors 614, 498 as previously described, and dart 60 (which includes head 70 and skirts 72 as previously described) is flowed axially through throughbores 612, 468 of connecting member 610 and sleeve 460 until head 70 lands and engages on landing surface 482 within throughbore 486 of downhole landing sleeve 480. As will be described in more detail below, the landing of dart 60 upon landing surface 482 causes central landing assembly 420 to transition or actuate from a first or initial position shown in Figure 19 to a second position shown in Figure 20.

[0099] In particular, when head 70 of dart 60 is engaged with landing surface 482 as previously described, skirts 72 sealingly engages radially inner surface 460d within throughbore 468 of sleeve 460. As a result, fluid (e.g., cement 54 in Figures 2-5) is prevented (or at least restricted) from flowing through throughbore 468 of central sleeve 460 and into and past throughbore 486 of downhole landing sleeve 480, so that an axial load is placed on sleeves 460, 480 via dart 60. Eventually this axial load causes shear pins 667 extending between uphole connecting member 610 and central sleeve 460 to fail such that sleeves 460, 480 transition axially within outer housing member 470 from the first position of Figure 19 to the second position of Figure 20 where downhole end 480b of lower landing sleeve 480 is engaged with uphole end 490a of downhole connecting member 490, and ports 462 are axially aligned with a portion of annulus 421. Accordingly, when central landing assembly 620 transitions or actuates to the second position of Figure 20, a bypass flow path is established that allows the fluid uphole of dart 60 (e.g., cement 54 shown in Figures 2-5) to flow around landed dart 60 within the landing sub 600. In particular, the bypass flowpath extends from throughbore 468 of sleeve 460, through ports 462, into annulus 421 , and back into throughbore 486 of sleeve 480 via ports 484 downhole of dart 60. As a result, the arrangement of landing sub 600 facilitates cementing operations utilizing only a single dart (e.g., dart 60), which may be desirable in some circumstances.

[0100] Embodiments of a landing sub (e.g., landing subs 200, 300, 400, 500, 600) have been disclosed herein for use within a wellbore tubular string (e.g., casing 20) that provide actuatable bypass flow paths to enable flow around a landed flowable valve member (e.g., darts 60, 80) to facilitate and improve operations within the wellbore tubular (e.g., cementing operations). In addition, at least some embodiments of the landing subs disclosed herein (e.g., landing subs 200, 300) include an uphole landing surface that is deployed as a result of a first flowable valve member landing on a downhole landing surface. As a result, a second flowable valve member, being of the same size as the first flowable valve member, may be subsequently landed within the same landing sub uphole of the first flowable valve member, which greatly simplifies wellbore operations utilizing multiple such flowable valve members.

[0101] While exemplary embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the scope or teachings herein. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of the systems, apparatus, and processes described herein are possible and are within the scope of the disclosure. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims. Unless expressly stated otherwise, the steps in a method claim may be performed in any order. The recitation of identifiers such as (a), (b), (c) or (1 ), (2), (3) before steps in a method claim are not intended to and do not specify a particular order to the steps, but rather are used to simplify subsequent reference to such steps.

Claims

CLAIMS What is claimed is:

1. A landing assembly for use within a subterranean wellbore, the landing assembly comprising:

an outer housing having a central axis and configured to be coaxially coupled to a tubular string; and

a central landing assembly disposed within the outer housing, the central landing assembly comprising a first landing surface and a second landing surface that is axially uphole of the first landing surface;

wherein the central landing assembly is configured to actuate from a first position to a second position, upon engagement of a first flowable valve member with the first landing surface; and

wherein the second landing surface is configured to translate radially inward toward the central axis when the central landing assembly actuates from the first position to the second position.

2. The landing assembly of claim 1 , wherein the central landing assembly is configured to translate axially within the outer housing to actuate from the first position to the second position.

3. The landing assembly of claim 2, wherein the second landing surface is defined by a plurality of engagement members that are configured to actuate radially inward toward to the central axis when the central landing assembly is actuated from the first position to the second position.

4. The landing assembly of claim 3, wherein the engagement members comprise a plurality of dogs slidably disposed within a plurality of apertures extending radially within the central landing assembly.

5. The landing assembly of claim 3, wherein the engagement members comprise a plurality of axially extending collets.

6. The landing assembly of claim 2, further comprising:

an annulus between the outer housing and the central landing assembly;

wherein the central landing assembly further comprises a first plurality of ports and a second plurality of ports wherein the first plurality of ports are disposed on an axially opposite side of the first landing surface from the second plurality of ports;

wherein the second plurality of ports are not in fluid communication with the annulus when the central landing assembly is in the first position; and wherein the second plurality of ports are in fluid communication with the annulus when the central landing assembly is in the second position.

7. The landing assembly of claim 6, wherein the first plurality of ports are in fluid communication with the annulus when the central landing assembly is in both the first position and the second position.

8. The landing assembly of claim 7, wherein the second plurality of ports is axially disposed between the first landing surface and the second landing surface.

9. The landing assembly of claim 8, wherein the central landing assembly comprises: a first landing sleeve comprising the first landing surface, wherein the first plurality of ports extend radially through the first landing sleeve;

a second landing sleeve, comprising the second landing surface, wherein the second plurality of ports extend radially through the second landing sleeve; and

a central sleeve coupled to and disposed axially between each of the first landing sleeve and the second landing sleeve, wherein the central sleeve comprises a third plurality of ports, wherein the third plurality of ports are aligned with the second plurality of ports when the central landing assembly is in both the first position and the second position.

10. The landing assembly of claim 9, wherein the central landing assembly is configured to actuate from the second position to a third position upon engagement of a second flowable valve member with the second landing surface, wherein the second plurality of ports are misaligned with the third plurality of ports when the central landing assembly is in the third position.

1 1 . The landing assembly of claim 10, wherein the second landing sleeve is configured to translate axially relative to the central sleeve when the central landing assembly is actuated from the second position to the third position.

12. A landing assembly for use within a subterranean wellbore, the landing assembly comprising:

a central landing assembly disposed within the outer housing;

an annulus between the outer housing and the central landing assembly;

wherein the central landing assembly comprises:

a first landing surface;

a first plurality of ports; and

a second plurality of ports;

wherein the first plurality of ports is disposed on an axially opposite side of the first landing surface from the second plurality of ports; and wherein the central landing assembly is configured to actuate from a first position, in which the second plurality of ports are not in fluid communication with the annulus, to a second position in which the second plurality of ports are in fluid communication with the annulus, upon engagement of a first flowable valve member with the first landing surface.

13. The landing assembly of claim 12, wherein the first plurality of ports are in fluid communication with the annulus when the central landing assembly is in both the first position and the second position.

14. The landing assembly of claim 13, wherein the central landing assembly further comprises:

a first landing sleeve, further comprising the first landing surface;

a second landing sleeve, further comprising a second landing surface; and a central sleeve coupled to and disposed axially between each of the first landing sleeve and the second landing sleeve.

15. The landing assembly of claim 14, wherein the first plurality of ports extend radially through the first landing sleeve;

wherein the second plurality of ports extend through the second landing sleeve; and

wherein the central sleeve comprises a third plurality of ports that are aligned with the second plurality of ports when the central landing assembly is in both the first position and the second position.

16. The landing assembly of claim 15, wherein the central landing assembly is configured to actuate from the second position to a third position upon engagement of a second flowable valve member with the second landing surface, wherein when the central landing assembly is in the third position, the second plurality of ports are misaligned with the third plurality of ports

17. The landing assembly of claim 14, wherein the first plurality of ports extend radially through the first landing sleeve, and wherein the second plurality of ports extend through the central sleeve.

18. The landing assembly of claim 12, further comprising a burst disc mounted to the outer housing; wherein the burst disc is not in fluid communication with a central throughbore of the first landing sleeve when the central landing assembly is the first position; and

wherein the burst disc is in fluid communication with the central throughbore of the first landing sleeve when the central landing assembly is in the second position.

19. A method, comprising:

(a) coupling a landing assembly to a tubular string, the landing assembly having a central axis;

(b) inserting the landing assembly and the tubular string within a subterranean wellbore;

(c) flowing a first flowable valve member into the tubular string;

(d) landing the first flowable valve member on a first landing surface within the landing assembly;

(e) opening a bypass flow path as a result of (d), wherein the bypass flow path extends from a first plurality of ports in the landing assembly that are uphole of the first landing surface to a second plurality of ports in the landing assembly that are downhole of the first landing surface;

(f) flowing a second flowable valve member into the tubular string;

(g) landing the second flowable valve member on a second landing surface; and

(h) closing the bypass flow path as a result of (g).

20. The method of claim 19, further comprising actuating the second landing surface from a radially withdrawn position to a radially collapsed position as a result of (d).