Patent Publication Number: US-2023139858-A1

Title: External sleeve cementer

Description:
BACKGROUND 
     When completing a subterranean well, casing is typically inserted into the wellbore and secured in place by injecting cement within the casing. The cement is forced through a lower end of the casing and into an annulus between the casing and wellbore wall. A displacement fluid is pumped into the casing above a plug to urge the plug downward through the casing to extrude the cement from the casing outlet and back up into the annulus. In some instances, it is impossible or impractical to cement the entire well. 
     To overcome the problems of a single stage cement process, the casing string is cemented in sections, which is known as a staging process. Staging involves placing cement staging tools integral within the casing string; the staging tools allow cement to flow downward therethrough to a lower section of the casing string during primary or first stage cementing operations. When the portion of the casing string below the particular staging tool is cemented to the well, the staging tool will divert cement into the surrounding annulus where the cement can flow upwards in the annulus. 
     At times, it is desired to cancel a stage of cementing after the tool has been lowered into the wellbore. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic showing a stage cementing tool in a wellbore. 
         FIG.  2    is a cross section of a stage cementing tool in a run-in position. 
         FIG.  3    is a cross section of the stage cementing tool of  FIG.  2    in a set position. 
         FIG.  4    is a cross section of the stage cementing tool of  FIG.  2    in a cementing position. 
         FIG.  5    is a cross section of the stage cementing tool of  FIG.  2    in a closed or completed position. 
         FIG.  6    is a cross section of the stage cementing tool of  FIG.  2    moved to the set position with a cancellation plug. 
         FIG.  7    is a cross section of the stage cementing tool of  FIG.  2    with an opening plug and a cancellation plug. 
         FIG.  8    is an expanded view of a portion of the mandrel. 
     
    
    
     DESCRIPTION OF AN EMBODIMENT 
     In the drawings and description that follow, like parts are typically marked throughout the specification and drawings with the same reference numerals, respectively. In addition, similar reference numerals may refer to similar components in different embodiments disclosed herein. The drawing figures are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. The present invention is susceptible to embodiments of different forms. Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is not intended to limit the invention to the embodiments illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed herein may be employed separately or in any suitable combination to produce desired results. 
     Unless otherwise specified, use of the terms “connect,” “engage,” “couple,” “attach,” or any other like term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described. 
     Unless otherwise specified, use of the terms “up,” “upper,” “upward,” “up-hole,” “upstream,” or other like terms shall be construed as generally toward the surface; likewise, use of “down,” “lower,” “downward,” “down-hole,” “downstream,” or other like terms shall be construed as generally away from the surface, regardless of the wellbore orientation. Use of any one or more of the foregoing terms shall not be construed as denoting positions along a perfectly vertical axis.  FIG.  1    schematically discloses a stage cementing tool  15  disposed in a wellbore  10 . Stage cementing tool  15  is connected in a casing  5 .  FIG.  1    also shows cement below stage cementing tool  15  which will have occurred in a prior cementing stage. An annulus  20  is defined by and between casing  5  and wellbore  10  and thus between stage cementing tool  15  and wellbore  10 . Stage cementing tool  15  has a run-in position  25 , shown in  FIG.  2   , a set position  30  shown in  FIG.  3   , a cementing position  32  shown in  FIG.  4    and a completed position  34  shown in  FIG.  5   . As is evident from the drawings, in the cementing and completed positions the tool  15  remains in the set position. When referred to herein as the set position, it is that position when the packer described herein is set, but prior to the time the stage cementing tool  15  moves to the cementing position. Stage cementing tool  15  also has two cancelled positions, which occur when it is determined that no cement is to be placed in the annulus through stage cementing tool  15 . The first cancelled position  36  is show in  FIG.  6    and the second cancelled position  38  is shown in  FIG.  7   . 
     Stage cementing tool  15  comprises a mandrel  40  with upper end  42  and lower end  44 . Upper and lower ends  42  and  44  are both connectable in casing  5  and may form a part thereof. Mandrel  40  defines a central flow passage  46  therethrough. A plurality of first longitudinal slots  48  are defined in mandrel  40 . First longitudinal slots  48  are spaced around mandrel  40  and may be referred to as a plurality of circumferentially spaced first longitudinal slots. A plurality of second longitudinal slots  50  are defined in mandrel  40 . Second longitudinal slots  50  are spaced around mandrel  40  and may be referred to as a plurality of circumferentially spaced second longitudinal slots. Second longitudinal slots  50  are defined in mandrel  40  above and longitudinally spaced from the plurality of first longitudinal slots  48 . Longitudinal slots  48  have upper end  52  and lower end  54 . Longitudinal slots  50  have upper end  56  and lower end  58 . Mandrel  40  has an outer surface  60  and an inner surface  62 . A groove containing an O-ring seal  49  is defined in outer surface  60  of mandrel  40  below the plurality of first longitudinal slots  48 . A groove  59  is defined in inner surface  62  of mandrel  40  below second longitudinal slots  50 . A bottom of groove  59  defines an upward facing shoulder  61 . 
     A packer  64  that is movable from an unset position as shown in  FIG.  2    to the set position shown in  FIG.  3    is disposed about mandrel  40 . Packer  64  comprises a packer element  66  that is an expandable packer element and a fixed wedge  68  disposed about mandrel  40  below packer element  66 . A setting sleeve  70  that is movable on mandrel  40  is disposed about mandrel  40 . A body lock ring  72  is disposed between setting sleeve  70  and outer surface  60  of mandrel  40 . Body lock ring  72  will prevent setting sleeve  70  from moving upwardly relative to mandrel  40  after the packer  64  is moved to the set position. Body lock rings are known in the art, and act like a ratchet so that upward movement of setting sleeve  70  is prevented after each incremental downward movement. A plurality of shear pins  74  detachably connect setting sleeve  70  to mandrel  40 . O-ring seal  49  provides a seal between setting sleeve  70  and mandrel  40  below first longitudinal slots  48 . 
     Stage cementing tool  15  comprises a cementing valve  80 . Cementing valve  80  comprises opening sleeve  82  and setting sleeve  70 .  FIG.  2    shows the first position  84  of opening sleeve  82  and setting sleeve  70 . First position  84  of the opening sleeve  82  and setting sleeve  70  is the run-in position of cementing tool  15 . Opening sleeve  82  is connected to setting sleeve  70  with at least one and preferably a plurality of drive pins  86  that are shearable drive pins  86 . Drive pins  86  extend through the plurality of first longitudinal slots  48 . Thus, opening sleeve  82  and setting sleeve  70  are connected to one another and are movable together. Setting sleeve  70  has upper end  90  and lower end  92 . A setting wedge  94  is defined at lower end  92  of setting sleeve  70 . Setting sleeve  70  has inner surface  96 , outer surface  98  and a plurality of cement flow ports  100  defined therein. Cement flow ports  100  may comprise circular ports, or elongated slots. In the embodiment described, there are sixteen (16) first longitudinal slots  48  equally spaced around mandrel  40  and sixteen (16) cement flow ports  100  equally spaced around setting sleeve  70 , but other numbers of flow ports  100  and longitudinal slots  48  may be used. In the cementing position  32  the central flow passage  46  is communicated with annulus  20  through the plurality of first longitudinal slots  48  and cement flow ports  100 . Because there are a plurality of flow ports  100  through which cement is communicated into annulus  20 , the placement of cement around the entire circumference of the cementing tool  15  and casing  5  is accomplished. Prior art tools normally include ports with rupture disks, and only one flow port that opens to allow cement to pass therethrough, making it difficult to achieve universal placement of cement, which is easily accomplished with the cementing tool disclosed herein. 
     In a second position  102  of the setting sleeve  70  and opening sleeve  82  the plurality of circumferentially spaced first longitudinal slots  48  are blocked by opening sleeve  82  such that no flow from the central flow passage  46  therethrough is allowed. However, in the second position  102 , which is the set position  30  of the stage cementing tool  15 , first longitudinal slots  48  in mandrel  40  are aligned with and communicated with cement flow ports  100  in setting sleeve  70 . 
     Opening sleeve  82  has upper end  104 , lower end  106 , inner surface  108  and outer surface  110 . An opening sleeve seat  112  is defined on opening sleeve  82  and is preferably defined on inner surface  108  thereof between the upper and lower ends  104  and  106  respectively. Opening sleeve seat  112  is sized to receive an opening plug  114  which will be described in more detail hereinbelow. A lock ring  118  is disposed in a groove  120  in the outer surface  110  of opening sleeve  82 . O-rings  122  may be disposed in grooves  124  in outer surface  110  of opening sleeve  82 . 
     A drive sleeve  130  is disposed in mandrel  40  above opening sleeve  82 . Drive sleeve  130  has upper end  132 , lower end  134 , inner surface  136  and an outer surface  138 . A lock ring  140  is disposed in a groove  142  in outer surface  138 . A drive sleeve seat  144  is defined at upper end  132  of drive sleeve  130 . Drive sleeve seat  144  may be a separate piece connected to drive sleeve  130  or may simply be defined at the upper end thereof. Drive sleeve seat  144  is sized to receive and engage a drive plug  146  placed into casing  5 . The drive plug  146  may be a closing plug which will be operable to prevent communication between central flow passage  46  and the annulus  20 , or may be a cancellation plug  150  which may be dropped into casing  5  to prevent cement from flowing from the central flow passage  46  to annulus  20  if it is determined that the cementing is to be cancelled and no cement is to be flowed into the annulus through stage cementing tool  15 . An O-ring  152  may be disposed in a groove  154  in outer surface  138  of drive sleeve  130 . O-ring  152  will sealingly engage mandrel  40 . 
     A closing sleeve  160  has upper end  162 , lower end  164 , inner surface  166  and outer surface  168 . Outer surface  168  has seals  170  disposed in grooves  172 . Seals  170  engage the inner surface  96  of setting sleeve  70  such that closing sleeve  160  and setting sleeve  70  are sealingly engaged. Closing sleeve  160  is detachably connected to mandrel  40  with shear pins  174 . Closing sleeve  160  is positioned above setting sleeve  70 , and extends downward on mandrel  40  so that a portion of closing sleeve  160  is disposed between setting sleeve  70  and mandrel  40 . Mandrel  40  has grooves  176  with O-ring seals  178  therein that seal against closing sleeve  160 . Closing sleeve  160  is connected to drive sleeve  130  with drive pins  175  and is movable therewith. Drive pins  175  extend through longitudinal slots  50 . 
     In operation, stage cementing tool  15  is lowered into a desired location in the well on casing  5 . Once the desired location is reached, cement is pumped through casing  5 , out a bottom of the casing  5  and into annulus  20 . After cement is placed in annulus  20 , a determination may be made as to whether or not annulus  20  has a sufficient amount of cement so that no additional cement needs to be placed in annulus  20  through cementing tool  15 . This determination is made by means known in the art, for example by observing whether there are cement returns at the surface. In situations in which the determination is made that no cement is to be flowed and as a result the stage cementing job is cancelled, a cancellation plug  150  may be dropped into the casing  5 . That process is explained in more detail hereinbelow. 
     If it is determined that second stage cementing is to occur and cement is to be flowed into annulus  20  through cementing tool  15  a freefall opening plug  114  is dropped into casing  5  and is allowed to free fall downwardly therein through any fluid in the casing until it engages opening sleeve seat  112 . Once opening sleeve seat  112  is engaged by opening plug  114 , pressure thereabove is increased to cause opening sleeve  82  to move from the first position shown in  FIG.  2    to the second position shown in  FIG.  3   . As is apparent from the drawings, opening sleeve seat  112  is located in opening sleeve  82  such that the opening plug  114  landed on opening sleeve seat  112  will be positioned below upper end  104  of opening sleeve  82 . The setting sleeve  70  is movable with opening sleeve  82  such that the movement of opening sleeve  82  will move the setting sleeve  70  to its second position  102 . Opening sleeve  82  and setting sleeve  70  are initially held in first position by shear pins  74  and by packer  64 . 
     Drive pins  86  will slide downwardly in the plurality of first longitudinal slots  48  from the upper end  52  to the lower end  54  thereof when opening sleeve  82  and setting sleeve  70  move to their second positions. The setting sleeve  70  in its second position moves the packer  64  to its set position against the well. This may be referred to as the set position of the stage cementing tool  15 . 
     In order to move the tool to the cementing position  32 , additional pressure is applied in the casing and drive pins  86  will break and opening sleeve  82  will be moved to its third position  180 . In the third position of the opening sleeve  82 , lock ring  118  will expand outwardly into a groove  182  in inner surface  62  of mandrel  40 . Lock ring  118  prevents the opening seat from moving upwardly once it is moved to its third position. A seat retainer  186  disposed in mandrel  40  will prevent opening sleeve  82  from moving downwardly past its third position  180 . Opening sleeve  82  moves relative to mandrel  40  and to setting sleeve  70  when it moves to the third position. Setting sleeve  70  will remain in its second position  102 . This position which is shown in  FIG.  4    is referred to as the cementing position. In the cementing position  32 , cement may be communicated through the first longitudinal slots  48  and through flow ports  100  to annulus  20 . In the cementing position shown in  FIG.  4   , an annular space  184  is defined by and between mandrel  40  and setting sleeve  70  and fluid, such as cement must flow therethrough to pass through flow ports  100  into annulus  20 . 
     Once a desired amount of cement has been flowed into annulus  20  a drive plug is displaced into casing  5 . In the case where cement is flowed into the annulus  20 , the drive plug is a closing plug  148 . The closing plug  148  may be of a type known in the art that has wipers  149  thereon so that it will urge cement downwardly in casing  5 . Closing plug  148  is pumped into casing  5  and will push cement ahead of it through the flow path created by first longitudinal slots  48  and cement flow ports  100 . Once closing plug  148  engages drive sleeve seat  144  pressure is increased to break shear pins  174  that connect closing sleeve  70  to mandrel  40 . 
     Once shear pins  174  break, drive sleeve  130  and closing sleeve  160  will move downwardly together. The lower end of closing sleeve  160  will be positioned below cement flow ports  100  and will sealingly engage the inner surface  96  of setting sleeve  70  to prevent communication from central flow passage  46  of mandrel  40  into annulus  20 . The position shown in  FIG.  5    is the completed position of the tool  15 , and closing sleeve  160  and drive sleeve  130  are in their second positions. When drive sleeve  130  is in its second position lock ring  140  is received in groove  59  in mandrel  40 . Shoulder  61  on mandrel  40  will prevent any further downward movement of drive sleeve  130 , for example if pressure is increased thereabove. This is a safety feature to account for increases in pressure for any reason, or when an unexpected or inadvertent increase occurs. 
     If it is determined that the cement displaced into the annulus  20  through the lower end of casing  5  is sufficient such that second stage cementing is not to be performed with stage cementing tool  15 , cementing can be cancelled easily with the stage cementing tool  15 . In order to cancel a second stage cementing job a drive plug, which in the case of a cancellation process is a free fall cancellation plug  150 , is dropped into casing  5  and allowed to free fall until it engages drive sleeve  130 . When the determination is made after the cementing tool  15  is lowered into the well and prior to moving the opening sleeve  82 , the cancellation plug  150  is dropped into casing  5 . Cancellation plug  150  will not engage the inner surface of the casing and requires no pumping. Cancellation plug  150  simply drops through any fluid in the casing and lands on drive sleeve seat  144 . Pressure is then increased above cancellation plug  150  to move drive sleeve  130  downward to engage opening sleeve  82 , and to move opening sleeve  82  and setting sleeve  70  to the set position of the tool  15  as depicted in  FIG.  7   . Drive sleeve  130  pushes opening sleeve  82  down in mandrel  40 , moving setting sleeve  70  to the second position which sets the packer  64 . Closing sleeve  160  will move down on mandrel  40  with drive sleeve  130  and communication between central flow passage  46  and annulus  20  is prevented during the entire cancellation process, so that there is no chance of communication therebetween during the cancellation of the cementing job. As shown in  FIG.  7    opening sleeve  82  covers first longitudinal slots  48  and closing sleeve  160  is positioned between mandrel  40  and setting sleeve  70  to block flow ports  100  and prevent communication therethrough. With prior art tools, there is a moment of time in which communication from a flow passage of the prior art tool is communicated with the well annulus during the cancellation process. With known second stage cementing tools, there is a temporary (very short) time frame when sleeves are shifting in which there is communication from the central flow passage of the tool to the annulus. This can create a risk of fluid inflow from the annulus to the central flow passage of the tool, a lack of pressure integrity during the cancellation process, a potential injection of well fluids into cement and seals crossing flow ports. The stage cementing tool  15  completely prevents communication between the central flow passage  46  of stage cementing tool  15  and the annulus  20  during the cancellation process. The foregoing cancellation process may be referred to as the primary cancellation process, in which the determination to cancel is made prior to the shifting of the opening sleeve, or any other sleeves. 
     In some cases, the cementing tool  15  may be moved to the cementing position  32 , and then the determination is made to cancel. In those situations, a cancellation plug  150  is dropped as described above. The cancellation process occurring after the opening sleeve  82  has been shifted may be referred to as the secondary cancellation process. In the secondary cancellation process the cancellation plug  150  will free fall downward until it engages drive sleeve seat  144 . Opening plug  114 , which is engaged with opening sleeve seat  112 , is located far enough below the upper end  104  of opening sleeve  82  to allow cancellation plug  150  to land. Such an arrangement is not feasible with prior art tools. Prior art tools are generally opened with a plug that engages the upper end of the prior art opening sleeve. As a result, there is no room for a cancellation plug. Instead, a closing plug with wipers must be used, and additional cement pumped into the annulus ahead of the closing plug even though the additional cement is not needed. The stage cementing tool  15  disclosed herein allows a job to be cancelled after an opening plug has engaged opening sleeve  82  and the tool  15  is moved to the cementing position. 
     Embodiment 1: A stage cementing tool for use in a wellbore comprising a mandrel having a plurality of circumferentially spaced first longitudinal slots and a plurality of circumferentially spaced second longitudinal slots, the plurality of circumferentially spaced second longitudinal slots being spaced longitudinally from the plurality of circumferentially spaced first longitudinal slots, an opening sleeve disposed in the mandrel in a first position and movable relative thereto, a setting sleeve disposed about the mandrel in a first position and movable relative thereto, the setting sleeve connected to the opening sleeve with connecting pins extending through the longitudinal slots in the plurality of the circumferentially spaced first longitudinal slots, the opening sleeve and setting sleeve movable together, the drive sleeve disposed in the mandrel above the opening sleeve and movable relative to the mandrel, and a closing sleeve disposed about the mandrel and connected to the drive sleeve with drive pins extending through the plurality of circumferentially spaced second longitudinal slots, the drive sleeve and closing sleeve movable together. 
     Embodiment 2: The stage cementing tool of embodiment 1 further comprising a settable packer disposed about the mandrel, the opening sleeve and setting sleeve movable together to a second position in which the setting sleeve moves the packer from an unset to a set position against the wellbore. 
     Embodiment 3: The stage cementing tool of embodiment 2, the drive sleeve engageable with the opening sleeve and movable to a second position of the drive sleeve, the drive sleeve operable to engage and move the opening sleeve and the setting sleeve to the second position without establishing communication between a central flow passage of the stage cementing tool and an annulus defined by the stage cementing tool and the wellbore. 
     Embodiment 4: The stage cementing tool of either of embodiments 2 or 3, further comprising a lock ring disposed about the drive sleeve, the mandrel having an upward facing shoulder thereon, the upward facing shoulder engageable with the lock ring on the drive sleeve to prevent the drive sleeve from moving past the second position of the drive sleeve. 
     Embodiment 5: The stage cementing tool of any of embodiments 2-4, the opening sleeve having an opening seat defined thereon, the opening sleeve movable from the first to the second position upon the application of pressure above an opening plug landed on the opening seat, the opening sleeve movable relative to the mandrel and the setting sleeve to a third position in the mandrel in which communication is permitted through the plurality of circumferentially spaced first longitudinal slots from a central flow passage of the mandrel to an annulus defined between the cementing tool and the wellbore. 
     Embodiment 6: The stage cementing tool of embodiment 5, the setting sleeve having a plurality of flow ports defined therethrough, the central flow passage communicated with the annulus through the plurality of circumferentially spaced first longitudinal slots and the flow ports in the setting sleeve when the opening sleeve is in the third position. 
     Embodiment 7: The stage cementing tool of either of embodiments 5 and 6, the closing sleeve being movable from a first closing sleeve position to a second closing sleeve position in which the closing sleeve blocks the flow ports in the setting sleeve to prevent communication therethrough to the annulus. 
     Embodiment 8: The stage cementing tool of any of embodiments 2-7 further comprising an opening plug landed on an opening seat defined in the opening sleeve and a drive plug landed on a seat defined by the driving sleeve. 
     Embodiment 9: A method comprising providing a stage cementing tool, the stage cementing tool comprising a mandrel defining a central flow passage therethrough and having a plurality of circumferentially spaced first longitudinal slots and a plurality of circumferentially spaced second longitudinal slots defined therein, the plurality of circumferentially spaced second longitudinal slots being longitudinally spaced from the plurality of circumferentially spaced first longitudinal slots; an opening sleeve disposed in the mandrel in a first position covering the plurality of circumferentially spaced first longitudinal slots and movable relative to the mandrel to allow communication through the plurality of circumferentially spaced first longitudinal slots; a drive sleeve disposed in the mandrel above the opening sleeve; and drive pins extending through at least some of the plurality of circumferentially spaced second longitudinal slots connecting the drive sleeve with a closing sleeve disposed about the mandrel; the method comprising lowering the stage cementing tool into a wellbore on a casing to a desired location; dropping a cancellation plug into the casing to cancel cementing through the stage cementing tool without establishing communication between the central flow passage and the well. 
     Embodiment 10: The method of embodiment 9, the cementing tool further comprising a packer disposed about the mandrel and a setting sleeve disposed about the mandrel, the setting sleeve connected to and movable with the opening sleeve, the method further comprising moving the opening sleeve and setting sleeve downward to move the packer to a set position against the wellbore. 
     Embodiment 11: The method of either of embodiments 9 or 10, wherein the setting step occurs after the cancellation plug is displaced into the casing. 
     Embodiment 12: The method of embodiment 11, the setting step comprising engaging a seat defined on the drive sleeve with the cancellation plug; increasing the pressure in the casing after the cancellation plug has engaged the drive sleeve; and pushing the opening sleeve downwardly in the mandrel with the drive sleeve to move the packer to the set position. 
     Embodiment 13: A stage cementing tool for use in a wellbore comprising a casing, the casing and wellbore defining an annulus therebetween; a mandrel having a plurality of first longitudinal slots defined therein and a plurality of second longitudinal slots defined therein connected in the casing, the plurality of second longitudinal slots spaced longitudinally from the plurality of first longitudinal slots; a drive sleeve disposed in the mandrel; an opening sleeve disposed in the mandrel in a first position covering the first longitudinal slots to prevent communication from a central flow passage of the mandrel to the annulus; a setting sleeve connected to the opening sleeve with a plurality of opening sleeve pins extending through the plurality of first longitudinal slots; and a packer disposed about the mandrel, the drive sleeve engageable with the opening sleeve and operable to move the opening sleeve and the setting sleeve to a second position in which the setting sleeve moves the packer to a set position against the wellbore. 
     Embodiment 14: The cementing tool of embodiment 13, the opening sleeve movable from the second to a third position to uncover the first plurality of longitudinal slots and allow communication from the central flow passage through the first plurality of longitudinal slots. 
     Embodiment 15: The cementing tool of embodiment 14, the setting sleeve having a plurality of flow ports therethrough, wherein cement communicated to the annulus is communicated through the plurality of first longitudinal slots and the plurality of flow ports in the setting sleeve. 
     Embodiment 16: The cementing tool of either of embodiments 14 and 15, the setting sleeve and the mandrel defining an annular space therebetween through which cement is flowed into the annulus. 
     Embodiment 17: The cementing tool of embodiment 16 further comprising the drive sleeve defining a drive sleeve seat for receiving a drive plug displaced into the mandrel and movable to a second position of the drive sleeve upon the application of pressure above the drive plug, wherein in the second position of the drive sleeve no communication is permitted through the plurality of circumferentially spaced first longitudinal slots to the annulus. 
     Embodiment 18: The cementing tool of any of embodiments 13-17, further comprising a freefall plug delivered into the mandrel and seated on the drive sleeve prior to setting the packer. 
     Embodiment 19: The cementing tool of any of embodiments 13-18, further comprising an opening plug delivered into the mandrel and seated on the opening sleeve and a freefall plug cancellation plug seated on the drive sleeve. 
     Embodiment 20: The cementing tool of embodiment 19, further comprising the freefall cancellation plug delivered into the mandrel and seated on the drive sleeve after the opening sleeve has moved to a third position in which communication to the annulus is established through the plurality of first longitudinal slots. 
     Thus, it is seen that the apparatus and methods of the present invention readily achieve the ends and advantages mentioned as well as those inherent therein. While certain preferred embodiments of the invention have been illustrated and described for purposes of the present disclosure, numerous changes in the arrangement and construction of parts and steps may be made by those skilled in the art, which changes are encompassed within the scope and spirit of the present invention.