Patent Publication Number: US-9428991-B1

Title: Multi-frac tool

Description:
RELATED APPLICATIONS 
     This application claims priority based upon U.S. Provisional Application Ser. No. 61/953,929 filed Mar. 16, 2014. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a downhole tool for selectively opening and closing multiple stages of hydrocarbon fluid flow during fracking operations and during production of hydrocarbons, and more particularly relates to an apparatus and system for receiving predetermined hydraulic pressure or other control signals from the surface to an opening port or a closing port to urge movement of a sliding frack valve to one of a plurality of positions that enable or lock down hydrocarbon fluid flow, respectively. When the downhole closing port receives pressure from the surface, the sliding frac valve is caused to slide in a prescribed direction wherein a slot contained thereon is misaligned with the slots contained on each of an open sleeve and a mandrel, both of which are immovable with their slots being permanently aligned. When the downhole opening port receives pressure from the surface, the sliding frack valve is caused to slide in an opposite direction wherein a slot contained thereon is aligned with the slots contained on each of an open sleeve and mandrel, thereby initiating or resuming hydrocarbon fluid in one of a plurality of frack stages or production zones. 
     BACKGROUND 
     There has been significant growth and developments in domestic applications of fracking during well completion operations. Special downwell equipment and downhole tools have been introduced to support and promote multi-zone production and during fracking operations, but a problem that has persisted is having the capability to efficiently open and close multiple frack stages and/or multiple production zones solely using permanently-placed downhole tools. 
     Furthermore, in order to promptly selectively shut down a particular frack stage or a particular production zone due to operational problems or change of circumstances, there is a paucity of tools and methodologies for effectively and reliably accomplish this crucial shut-down task without jeopardizing wellbore integrity. As will be readily appreciated by those skilled in that art, common approaches for handling this situation generally involve injecting cement into a wellbore which, unfortunately, shuts down production in all producing zones—not just the particular troublesome production zone. It will be understood that such approach adversely affects the plethora of pores permeating the producing zone and, indeed, requires substantial reworking if production from the wellbore were to be revived. 
     Those conversant in the art will understand that an intervention step would typically be prerequisite to address the challenge of selectively closing a particular frack stage or production zone in a multiple frack stage or multiple production zone scenario. There appears to have been a paucity of improvements in the art. The commonly used drop ball methodology for fracking seems to inherently preclude such selective opening and closing of stages or zones contemplated herein. Indeed, it should be evident that this drop ball approach precludes such opening and closing, and consequently requires that cementing be invoked to plug a wellbore which, of course, essentially undermines the well&#39;s prospects for further production. Sliding sleeve downhole tool embodiments have been applied to promote fracking using a series of plugs urged downhole under pressure. But, this sliding sleeve approach also significantly inhibits opening and closing as contemplated hereunder. Nevertheless, it appears that the heretofore most reliable method for shutting down and sealing a wellbore is to inject cement therein. 
     Accordingly, what is needed in the art is a downhole tool permanently emplaced within a wellbore using a packer affixed at each end thereof, having the inherent capability to selectively open and close multiple frack stages and multiple production zones without requiring not only a total shutdown of fracking operations or hydrocarbon production, but also just receiving a signal from the well surface that remotely triggers such specific opening and closing, in the absence of an additional intervening and costly step. 
     In view of these and other known deficiencies in the downhole art, it appears that selective opening and closing of multiple frack stages and multiple production zones has heretofore been and remains nonexistent. Accordingly, these limitations and disadvantages of the prior art are overcome with the present invention, wherein improved means and techniques are provided which are especially useful for using the multi-frac tool of the present invention with its in situ capability to effectively open and close frack stages and production zones. 
     SUMMARY 
     Embodiments of the present multi-frac tool pertain to selectively opening and closing a section of a plurality of frack sections constituting a frack stage. Embodiments afford a useful option of screening hydrocarbons during production to filter out particles of sand and other unavoidable downhole debris. 
     It will be seen that embodiments of the present invention enable downhole fracking operations to be segmented into up to 4 separate fracks contemplated to be as far apart 50 meters between each frack, whereupon a segment devolves to about 200 meters. This wellbore segmentation would be achieved using just one multi-frac tool of the present invention. 
     It will also be appreciated that, during production from a zone, if a problem should arise wherein production must cease, application of the instant downhole tool precludes usage of cement as is common in the art. Thus, by avoiding the prevalent cementing approach to abruptly cease production, the present invention inherently avoids typical wellbore damage and consequent undermining of other hydrocarbon producing zones. 
     Another important aspect of the present invention is that produced hydrocarbons can be filtered to separate sand and other impurities at the source in the wellbore, thereby preventing production pipe corrosion which is particularly advantageous since a variety of permanent production tools typically reside downhole during a well&#39;s lifetime. 
     It will be appreciated by those skilled in the art that the instant multi-frac tool, when disposed in an open position with all three slots being aligned, the sliding sleeve member would be positioned toward the bottom thereof, with a locking rib cage, in turn, positioned within the open sleeve and locked therein. As will become evident to those skilled in the art, considerable pressure will be prerequisite to compress the locking rib cage so that it vacates the recess, thereby enabling the sliding sleeve member to be urged into a corresponding closed position. It will be seen, that in this closed position, the sliding sleeve member would have slidably moved from one end of the tool to the other, wherein the locking rib cage is now disposed within another recess, the recess associated with the open sleeve member. It will become apparent that the sliding sleeve member slot is no longer aligned with the other two mandrel slots. Indeed, the sealing surface manifest in the sliding sleeve member will be blocking the passage of any flow either into or out of this sealing surface. 
     According to the present invention, to preclude flow, fluid pressure would be applied to at least one closing port preferably using a cup tool. Of course, it should be evident that a plurality of closing ports may be incorporated into embodiments hereof. Included on the mandrel is at least one channel that functions as a communication port. It will be appreciated that a plurality of such channels should preferably be arranged in a concentric and coplanar configuration to facilitate efficient linear inward flow 
     It is accordingly an object of the present invention to provide a downhole tool that reduces operating costs by precluding the necessity for conventional cementing. 
     It is another object of the present invention to provide a downhole tool that affords simple deployment. 
     It is yet another object of the present invention to provide a downhole frack tool that enables up to four frack zones to be selectively opened and closed without jeopardizing wellbore integrity and hydrocarbon production potential, with only a single trip downhole. 
     It is also an object and advantage of the present invention that embodiments may be used to selectively filter sand and other impurities out of hydrocarbon production at the downhole source, thereby avoiding or at least minimizing the occurrence of corrosion. 
     These and other objects of the present invention will become apparent from the following specifications and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts a frontal perspective view of an embodiment of the present invention. 
         FIG. 2A  depicts an enlarged view of the embodiment depicted in  FIG. 1 , disposed in an open condition. 
         FIG. 2B  depicts an enlarged view of the embodiment depicted in  FIG. 1 , disposed in a closed condition. 
         FIG. 3  depicts an isolated view of the open sleeve condition depicted in  FIG. 2A . 
         FIG. 4  depicts a simplified frontal perspective views of decompressed rib members contained within the rib cage of the embodiment depicted in  FIG. 1 . 
         FIG. 5  depicts an isolated frontal perspective view of a sliding frack valve of the embodiment depicted in  FIG. 1 . 
         FIG. 6  depicts a simplified schematic view of a frack perforation pattern disposed adjacent the embodiment of the present invention depicted in  FIGS. 1-5 . 
         FIG. 7  depicts a cross-sectional view of another embodiment of the present invention depicted in  FIG. 13 , corresponding to “no flow position with screen off” condition. 
         FIG. 8  depicts a cross-sectional view of the embodiment depicted in  FIGS. 7 and 13 , corresponding to “open flow position with screen off” condition. 
         FIG. 9  depicts a cross-sectional view of the embodiment depicted in  FIGS. 7 and 13 , corresponding to “open flow position with screen on” condition. 
         FIGS. 10A and 10B  depict enlarged cross-sectional views of the “no flow position with screen off” condition depicted in  FIG. 7 . 
         FIGS. 11A and 11B  depict enlarged cross-sectional views of the “open flow position with screen off” condition depicted in  FIG. 8 . 
         FIGS. 12A and 12B  depict enlarged cross-sectional views of the “open flow position with screen on” condition depicted in  FIG. 9 . 
         FIG. 13  depicts a frontal perspective view of the embodiment of the present invention depicted in  FIGS. 7-12 . 
         FIG. 14  depicts an isolated frontal perspective view of a sliding screen valve of a filtering screen embodiment of the present invention. 
         FIG. 15  depicts a frontal view of the sliding screen valve of the filtering screen embodiment depicted in  FIG. 14 , focusing on the seats for receiving locking rib cage members. 
         FIG. 16  depicts a frontal cut-away view of the sliding screen valve of the filtering screen embodiment depicted in  FIG. 14  and  FIG. 15 . 
     
    
    
     DETAILED DESCRIPTION 
     Reference is made herein to the figures in the accompanying drawings in which like numerals refer to like components. Now referring collectively to  FIGS. 1-5 and 7-16 , there are depicted embodiments of the present invention corresponding to downhole multi-frac tool that enables practitioners in the art to select one of a maximum of four frack zones to close during fracking operations or production of hydrocarbons for accommodating problems that may occur, without adversely affecting the integrity of the wellbore and future production of hydrocarbons. Accordingly, an embodiment of the present invention would be emplaced downhole at a predetermined depth in a wellbore after permanent production packers have been emplaced therein, and zonal shutdown would be expeditiously effectuated without interrupting other frack zones or production of hydrocarbons. 
     Referring now to  FIG. 1 , there is seen a frontal perspective view of a multi-frac tool  10  embodiment taught by the present invention. Open sleeve  40  is affixed to mandrel  70  with customer-specified threads  75  depicted at each end of mandrel  70 . At each end of embodiment  10  is end cap  15  A-B, Now referring to  FIGS. 2A-B , there is depicted an enlarged view of the embodiment depicted in  FIG. 1 , disposed first in an open condition and then disposed in a closed condition. Sliding frack valve  35  is disposed medially of open sleeve  40  and mandrel  70 . 
     As will become apparent to those skilled in the art, once the instant multi-frac tool is emplaced downhole and permanently situated connected to a packer pair (not shown). Mandrel  70  and open sleeve  40  remain fixed; only the sliding frack valve  35  moves along the mandrel as will be hereinafter described. Flow closing port  20  is shown at one end and flow opening port is shown at the opposite end thereof. It will be appreciated that each of these fluid flow ports should preferably comprise a plurality of channels that are preferably disposed in a concentric and coplanar configuration. Thus, to shut down fluid flow, hydraulic pressure would be applied to the flow closing port  20  whereupon there would be no communication between the reservoir and production in this zone being closed. According to the present invention, this shutdown is achieved when sliding frac valve  35  slides from left to right until the rib cage reaches the recess on the right side thereof and seats therein. Sliding frac valve  35  has thus been urged into a closed position wherein its slot  56  is misaligned with each of the inherently aligned mandrel slot  55 A and open sleeve slot  55 B. It will be seen that frack valve sealing surface  36  would be sandwiched between slot  55 B of open sleeve  40  and slot  55 A of mandrel  70 . Thus, fluid flow has been shut down, wherein there is neither flow in or out of the preferred embodiment. 
     On the contrary, fluid flow would be enabled if hydraulic pressure would be applied to the flow opening port  60  whereupon there would be communication between the reservoir and production in this zone being open. According to the present invention, this open condition is achieved when sliding frack valve  35  slides from right to left until the rib cage reaches the recess on the left side thereof and seats therein. Sliding frack valve  35  has thus been urged into an open position wherein its slot  56  is aligned with each of inherently aligned mandrel slot  55 A and open sleeve slot  55 B. It will be seen that frack valve surface would be sandwiched between slot  55 B of open sleeve  40  and slot  55 A of mandrel  70 . Thus, fluid flow out of the tool would be enabled for fracking and for injecting activity; and fluid flow into the tool would correspond to production of hydrocarbons from the reservoir to the surface. 
       FIG. 6  depicts a simplified schematic view of a frack perforation pattern disposed adjacent an embodiment of the present invention  10 . Shown therein, directed downhole, are four frack stages  85 A,  85 B,  85 C, and  85 D having plurality of perforations  80 , with the downhole tool  10  taught herein positioned downhole. As will be hereinafter explained, tool  10  enables a methodology for selectively opening and/or closing one or more of these four frack stages. For instance, to close one of up to four possible frack zones, a suitable signal would be sent downhole—illustrated herein by hydraulic pressure—through a closing port preferably located on the bottom side of tool  10 . This pressure signal urges the sliding frack valve to slide from one side of the tool to the other into a specially configured closed position, wherein the locking rib cage is seated within a corresponding recess to seal off this frack zone being shut down. This lock down sealing protocol taught by the present prevents hydrocarbon fluid from either entering or departing the designated frack zone—through the instant tool  10 . It will be seen that, if circumstances necessitate reopening a frack zone, then triggering hydraulic pressure would be applied to the opening port preferably located on the tool top side, the sliding frack valve would be urged to slide in the opposite direction toward the corresponding open position wherein the locking rib cage, disposed at the proximal end of the sliding frack valve, would be locked into a corresponding recess thereat. 
     It should be appreciated by those skilled in the art that, while the illustrations herein depict two positions of locking rib cage  50 , disposed on either side of the preferred embodiments, this is not intended to limit the scope of the self-contained closed flow and open flow system taught hereunder. Hence, embodiments hereof may be configured to accommodate a maximum of four frack stages or production zones by having a suitable variation of the infrastructure elucidated and illustrated herein. It will be understood that embodiments of the present invention enable a well to be subdivided into segments constituting either frac stages or production zones. Such novel segmentation enabled hereunder, in turn, enable selected segments—frack stages or production zones—to be opened and closed in a manner heretofore unknown in the art. 
     It will be understood that, for open condition depicted in  FIG. 2A , closing port  20  is shown inhibited or blocked from receiving inbound fluid flow, while opening port  60  is shown uninhibited and is poised to received inbound activation fluid pressure engendered from the surface through a cap tool or the like. On the other hand, in  FIG. 2B , there is seen a closed condition wherein opening port  60  is shown inhibited or blocked from receiving inbound fluid flow, while closing port  20  is shown uninhibited and is poised to received inbound activation fluid pressure engendered from the surface. 
     Still referring to  FIGS. 2A-B , there is seen locking rib cage  50  which encloses a plurality of ribs such as rib member  45  on each end hereof. Also shown is pair of cover rings  25  which sustain the integrity and arrangement of locking rib cage  50  as it is caused to move along with sliding frack valve  35  to which it is attached.  FIG. 3  depicts an isolated view of the open sleeve condition depicted in  FIG. 2A . There is seen recess members  41  and  42 , disposed at each end of tool  10  with open sleeve slot  55 A shown medially thereof. As a locking rib cage is caused to move from end to the other along with the sliding frack valve, this transition is stopped when the locking rib cage engages a recess and becomes enclosed therein. It will be appreciated that there is an inherent bias for sliding frac valve  35  to travel linearly along its path, thereby limiting rotational deviations thereof which would tend to interfere with proper alignment of sliding frzc valve slot  56  and fixed slots  55 A and  55 B. 
     A rib member contemplated herein is deformed strip of metal configured as depicted in simplified frontal perspective views of in  FIG. 4 . In particular, the compressed rib members shown would be contained within the locking rib cage of the present embodiment. Initially having a flat straight configuration having an elevated step-like middle portion with inclined surfaces of either side thereof, compression would cause the elevated middle portion to become level with the side portions, except that such downward movement of the middle portion tends to cause the each end portion to flare upwards. 
     Collectively referring now to  FIGS. 1-5 , there is seen the various positions occupied by individual ribs within an associated locking rib cage encasing a plurality of ribs as contemplated hereunder. As will be hereinafter described, when rib cage  50  is caused to move, its individual rib members are unseated from the outer surface of sliding frack valve  35  and urged to move along with sliding frack valve  35  to the other side of the tool and then become seated there in the proximal recess, either recess  41  or  42 , depending upon which side is implicated. The exterior surface of sliding frack valve  35  depicted in  FIG. 5  clearly depicts the profiles  37  and  38  thereon that facilitates locking rib cage  50  to be seated thereupon. It should be understood that the ribs  45  are always seated on the sliding frack valve either in a compressed or uncompressed disposition. It will be seen that movement of a locking rib cage  50 —either left or right—ceases when the recess  41  or  42  on the opposite end of the tool is reached and the locking rib cage  50  becomes positioned therewithin and immediately becomes uncompressed. 
     It will be seen that locking rib cage  51  or  52  would be emplaced under pressure in corresponding recess  41  or  42 , respectively at the end of slidable movement of sliding frack valve  35  either from left to right or from right to left, depending upon whether the pressure is applied to flow closing port  20  or flow opening port  60 , triggering a closed or open condition, respectively. It should be noted that, when the sliding frack valve  35  is disposed in the closed position, the locking rib cage would be seated within the recess of the open sleeve. Consequently, the sealing surface  36  associated with sliding frack valve  35  will be inhibiting fluid flow passage either into or out of the tool, since this sealing surface  36  has become aligned with mandrel slot  55 A and open sleeve slot  55 B. 
     Referring now to  FIG. 4 , there is seen plurality of rib members  50  which, as will become clear to those skilled in the art, are preferably encased within a locking rib cage wherein each rib member  45  is enclosed therein. Pair of cover ring members  25  enclose the locking rib cage to sustain the integrity and placement of the rib contained therein during compression and decompression thereof as contemplated hereunder. Each rib member  45 , preferably made from a deformed metal strip, is shown having a middle portion elevated relative to each end portion thereof. All of the plurality of ribs are disposed around the instant downhole tool. When pressure is applied downhole to either the flow opening port  60  or the flow closing port  20 , movement of sliding frack valve  35  which, in turn, causes locking rib cage  50  to transition from a recess member disposed at one end to the other opposite recess member. For instance, if the locking rib cage were to be caused to move left with the sliding frack valve to which it is attached, the ribs are no longer decompressed within a recess and become compressed due to entry into a smaller cross-sectional area than was available within the recess. Thus to move into the open sleeve, the ribs must be compressed. It should be understood this spring-like behavior manifest via a caged plurality of rib members may also be accomplished by other devices well known in the art. For example, the compression and decompression enabled via the rib cage and the plurality of deformed ribs contained therein could be effectuated via suitable springs or a series of Belleville rings washers or essentially any type of spring-like members that function to urge the sliding frac valve to decompress into its corresponding recess and remain therein until another signal is received from the surface to trigger further sliding action of the sliding frack valve and emplacement in the recess disposed at the opposite side of the instant multi-frac tool. 
     It will be appreciated that, according to the present invention, there typically is one set of ribs contained within a locking rib cage seated in a recess in an uncompressed condition. For example, when fluid pressure is received from the surface and input into flow closing port  20 , the sliding frack valve  35  is urged to slide from left to right. This sliding motion continues under pressure until the implicated locking rib cage with its compressed plurality of ribs reaches the right recess, whereupon the ribs expand into the extra space. 
     It will become apparent to those skilled in the art that this same behavior is manifest for an alternative embodiment of the present invention which incorporates a screen filtering feature into its multi-frac functionality. That is, besides the instant multi-frac tool taught herein having the profound ability to selectively open and close up to four frack or production zones, this alternative embodiment thereof also affords an ability to selectively filter out sand and other debris downhole in the reservoir as source thereof. Hence, it should be evident that virtually the same functionality is achieved based upon the analogous structure shown in  FIGS. 1-3 and 5 , pertaining to one embodiment comprising a sliding frack valve  35 , an open sleeve  40  and, of course, a mandrel  70 , on the one hand, and shown in  FIGS. 7-13  pertaining to another embodiment comprising these same components and a screen-related analogous infrastructure further comprising a screen off port  220 , a screen on port  360 , a sliding screen valve  230 , screen locking rib cage  251 , screen slot  256 , and screen  300 . 
     More particularly, referring now to  FIGS. 7-9 , there are depicted cross-sectional views of another embodiment of the present invention having an additional sleeve for accommodating a filtering screen feature. Thus,  FIG. 7  depicts a cross-sectional view of this screen embodiment corresponding to “no flow position with screen off” condition. Sliding frack valve  130  has been caused to slide from right to left into the no-flow position wherein locking rib cage  151  is sitting within recess  141 . Also, it is seen that there is a screen-off condition because screen locking rib cage is seated within recess  241 . Thus, in this arrangement, the present invention has shut down fluid flow and does not invoke a filtering screen. 
     Similarly,  FIG. 8  depicts a cross-sectional view of an embodiment of the present invention corresponding to “open flow position with screen off” condition and  FIG. 9  depicts a cross-sectional view corresponding to “open flow position with screen on” condition. Screen  300  is shown in on position in  FIG. 9 , being visibly active via slot  155 . Contrariwise, screen  300  is shown urged into an off position in  FIGS. 7 and 8 . There is seen screen off port  220  and screen on port  260 , sliding screen valve  230  and screen cover ring  225 . Also shown is customer specified thread  175 , extension  500 , flow closing port  120 , flow opening port  160 , and mandrel  170 . 
       FIGS. 10A and 10B  depict enlarged cross-sectional views of the “no flow position with screen off” condition depicted in  FIG. 7 . Shown therein is O-ring  105  representative of a plethora of O-rings permeated throughout the preferred embodiments—occasionally referred to as “Design I” and “Design II”—with Design II having the filtering screen option herein described.  FIGS. 11A and 11B  depict enlarged cross-sectional views of the “open flow position with screen off” condition depicted in  FIG. 8 . Similarly,  FIGS. 12A and 12B  depict enlarged cross-sectional views of the “open flow position with screen on” condition depicted in  FIG. 9 . Shown therein is sliding frack valve  130  and analogously functioning sliding screen valve  230 . 
     Now referring to  FIGS. 10-16 , there are depicted various views of the filtering screen embodiment  110  (embodiment II) of the present invention. Similar to the embodiment  10  depicted in  FIG. 1  corresponding to embodiment I which is devoid of a filtering screen, downhole tool  110  comprises open sleeve  240  is affixed to mandrel  170  with customer-specified threads  175  depicted at each end of mandrel  170 . At each end of embodiment  110  is end cap  215  A-B, This filter screen multi-frack tool would be emplaced downhole and preferably be permanently situated connected to a packer pair (not shown). Mandrel  170  and open sleeve remain fixed  140 ; only the sliding frack valve  135  moves along the mandrel as will be hereinafter described. Flow closing port  120  is shown at one end and flow opening port is shown at the opposite end thereof. It will be appreciated that each of these fluid flow ports should preferably comprise a plurality of channels that are preferably disposed in a concentric and coplanar configuration. Thus, to shut down fluid flow, hydraulic pressure would be applied to the flow closing port  120  whereupon there would be no communication between the reservoir and production in this zone being closed. According to the present invention, this shutdown is achieved when sliding frack valve  135  slides from left to right until the locking rib cage  151  reaches the recess  242  on the right side thereof and seats therein. Sliding frack valve  135  has thus been urged into a closed position wherein its slot  156  is misaligned with each of the inherently aligned mandrel slot  155 A and open sleeve slot  155 B. It will be seen that frack valve surface would be sandwiched between slot  155 B of open sleeve  140  and slot  155 A of mandrel  170 . Thus, fluid flow has been shut down, wherein there is neither flow in or out of this embodiment. 
     On the contrary, fluid flow would be enabled if hydraulic pressure would be applied to the flow opening port  160  whereupon there would be communication between the reservoir and production in this zone being open. According to the present invention, this open condition is achieved when sliding frack valve  135  slides from right to left until the locking rib cage  151  reaches the recess  141  on the left side thereof and seats therein. Sliding frack valve  135  has thus been urged into an open position wherein its slot  156  is aligned with each of inherently aligned mandrel slot  155 A and open sleeve slot  155 B. It will be seen that frack valve sealing surface  136  would be sandwiched between clot  155 B of open sleeve  140  and slot  155 A of mandrel  170 . Thus, fluid flow out of the tool would be enabled for fracking or into the tool for injecting activity; and fluid flow out of the tool would correspond to production of hydrocarbons from the reservoir to the surface. 
     For this filtering screen embodiment of the present invention, it will be appreciated that a similar structure and functional relationship exists for the intermediate sliding screen valve  230  and its associated components contemplated hereunder. In particular, open screen sleeve  240  is affixed to mandrel  170 . At each end of this screen embodiment is outer end cap  215  A-B, It will be understood that this filter screen multi-frac tool would be emplaced downhole and could be situated connected to packers or other downhole tools or to pipes. Mandrel  170  and open sleeve remain fixed  240 ; only the sliding frack valve  230  moves along the mandrel as will be hereinafter described. Screen closing port  220  is shown at one end and screen opening port  260  is shown at the opposite end thereof. It will be appreciated that each of these screen ports should preferably comprise a plurality of channels that are preferably disposed in a concentric and coplanar configuration. Thus, to shut down screen filtering, hydraulic pressure would be applied to the screen closing port  220  whereupon no filtering would be effectuated during fracking or production in this zone being closed. According to the present invention, this shutdown is achieved when sliding screen valve  230  slides from right to left until the locking rib cage  252  reaches the recess  242  on the left side thereof and seats therein. Sliding screen valve  230  has thus been urged into a no-screen position wherein its slot  256  is misaligned with each of the inherently aligned mandrel slot  255 A and open sleeve slot  255 B. Thus, the screen  300  has not been invoked, wherein filtering is not occurring. 
     On the contrary, screen filtering would be enabled if hydraulic pressure would be applied to the screen opening port  260 . According to the present invention, this open condition is achieved when sliding screen valve  230  slides from left to right until the screen locking rib cage  251  reaches the recess  241  on the right side thereof and seats therein. Sliding screen valve  230  has thus been urged into an active filtering position wherein its slot  256  is aligned with each of inherently aligned mandrel slot  255 A and screen open sleeve slot  255 B. 
     As will become apparent to those skilled in the art, once the instant multi-frac tool is emplaced downhole and situated proximal to a packer pair. The mandrel and open sleeve members remain fixed; only the sliding frack valve and sliding screen valve move along the mandrel as will be herein described. The locking rib cage and screen rib cage of the present invention are caused to slide along with the implicated sliding frack valve or sliding screen valve, as appropriate, and become engaged in a corresponding recess disposed at the end to which the sliding motion is directed. When the locking condition has been activated, this methodology locks out fluid flow from embodiments hereof and shuts down the frack stage or production zone; and either precludes or enables filtering of sand and particulate impurities as a function of whether the screen has been urged into a screen-on or screen-off position. Which of these screen conditions has been realized, as has been herein elucidated, is functionally related to the direction of the sliding movement of the sliding screen valve that has been urged from the surface, and the interaction between the locking screen rib cages disposed upon the sliding screen valve and their corresponding screen recesses. 
     Thus, it should be evident to those skilled in the art that the present invention teaches downhole tools having unique structure and functionality that enables up to four frack zones or production zones to be selectively opened or closed by receiving triggering signal via hydraulic downhole pressure or other means known in the art such as electrical signals. It is contemplated to within the scope of the present invention to subdivide a well into different segments or fracking up to four zones with a maximum of about 50 meters between fracks, wherein such a segment would devolve to about 200 meters. It has been shown hereunder that the instant multi-frac tool affords superior sealing characteristics which, of course, is especially useful to achieve a bona fide no-flow condition. 
     The following tabulation enumerates and identifies the various components comprising embodiments of the present invention. 
     
       
         
           
               
            
               
                   
               
               
                 Multi-Frac Tool Components 
               
            
           
           
               
               
               
            
               
                 Numeral 
                 Description 
                 Comments &amp; Explanation 
               
               
                   
               
               
                 10 
                 Multi-Frac tool 
                   
               
               
                 15A 
                 End cap 
                 Design I 
               
               
                 15B 
                 End cap 
                 Design I 
               
               
                 20 
                 Flow Closing port 
                 Design I 
               
               
                 25 
                 Cover ring 
                 Design I 
               
               
                 35 
                 Sliding frack valve 
                 Design I 
               
               
                 36 
                 Sealing surface 
                 Sealing surface in Sliding Frack  
               
               
                   
                   
                 Valve (design I) 
               
               
                 37 
                 Seats 
                 Locking rib member/cage seats in  
               
               
                   
                   
                 Sliding Frack Valve (design I), close  
               
               
                   
                   
                 to Sliding Frack Valve Slot 
               
               
                 38 
                 Seats 
                 Locking rib member/cage seats in  
               
               
                   
                   
                 Sliding Frack Valve (design I), close 
               
               
                   
                   
                 to Sliding Frack Valve sealing 
               
               
                   
                   
                 surface 
               
               
                 40 
                 Open sleeve 
                 Design I 
               
               
                 41 
                 Recess 
                 Recess in Open Sleeve Close to 
               
               
                   
                   
                 member 15A Design I 
               
               
                 42 
                 Recess 
                 Recess in Open Sleeve Close to  
               
               
                   
                   
                 member 15B Design I 
               
               
                 45 
                 Rib member 
                 Design I 
               
               
                 46 
                 Locking Rib member 
                 Sitting in 37 Design I 
               
               
                 47 
                 Locking Rib member 
                 Sitting in 38 Design I 
               
               
                 50 
                 Locking rib cage 
                   
               
               
                 51 
                 Locking Rib Cage 
                 Sitting in 37 Design I 
               
               
                 52 
                 Locking Rib Cage 
                 Sitting in 38 Design I 
               
               
                 55A, B 
                 Slot 
                 Refers to the 2 slots, the one in the  
               
               
                   
                   
                 Open Sleeve and the one in the  
               
               
                   
                   
                 Mandrel Design I 
               
               
                 56 
                 Slot 
                 Sliding Frack Valve Slot design I 
               
               
                 60 
                 Flow Opening port 
                 Design I 
               
               
                 65 
                 Rib housing cap 
                 Design I 
               
               
                 70 
                 Mandrel 
                 Design I 
               
               
                 75 
                 Customer Threads 
                 Design I 
               
               
                 80 
                 Plurality of 
                   
               
               
                   
                 Perforations 
                   
               
               
                 85A 
                 Frack stage 
                 Close to heal of vertical well 
               
               
                 85B 
                 Frack stage 
                 The 2 nd  from heal of vertical well 
               
               
                 85C 
                 Frack stage 
                 The 3 rd  from heal of vertical well 
               
               
                 85D 
                 Frack stage 
                 Close to bottom of horizontal well 
               
               
                 100 
                 Plurality of O-Rings 
                   
               
               
                 105 
                 Single O-Ring 
                   
               
               
                 115A 
                 End cap 
                 Design II 
               
               
                 115B 
                 End cap 
                 Design II Opposite end 
               
               
                 120 
                 Flow Closing Port 
                 Design II 
               
               
                 125 
                 Cover Ring 
                 Design II 
               
               
                 130 
                 Sliding frack valve 
                 Design II 
               
               
                 136 
                 Sealing surface 
                 Sealing surface in Sliding Frack  
               
               
                   
                   
                 Valve (design II) 
               
               
                 137 
                 Seats 
                 Locking rib member/cage seats in  
               
               
                   
                   
                 Sliding Frack Valve (design II), close 
               
               
                   
                   
                 to Sliding Frack Valve Slot 
               
               
                 138 
                 Seats 
                 Locking rib member/cage seats in 
               
               
                   
                   
                 Sliding Frack Valve (design II), close 
               
               
                   
                   
                 to Sliding Frack Valve sealing surface 
               
               
                 140 
                 Open sleeve 
                 Design II 
               
               
                 141 
                 Recess 
                 Recess in Open Sleeve Close to 
               
               
                   
                   
                 member 115A Design II 
               
               
                 142 
                 Recess 
                 Recess in Open Sleeve Close to  
               
               
                   
                   
                 member 115B Design II 
               
               
                 145 
                 Locking Rib member 
                 Design II 
               
               
                 146 
                 Locking Rib member 
                 Sitting in 137 Design II 
               
               
                 147 
                 Locking Rib member 
                 Sitting in 138 Design II 
               
               
                 150 
                 Locking Rib Cage 
                 Plurality of ribs Design II 
               
               
                 151 
                 Locking Rib Cage 
                 Sitting in 137 Design II 
               
               
                 152 
                 Locking Rib Cage 
                 Sitting in 138 Design II 
               
               
                 155A, B 
                 Slot 
                 Refers to the 2 slots, the one in the 
               
               
                   
                   
                 Open Sleeve and the one in the  
               
               
                   
                   
                 Mandrel Design II 
               
               
                 156 
                 Slot 
                 Sliding Frack Valve Slot design II 
               
               
                 160 
                 Flow Opening Port 
                 Design II 
               
               
                 170 
                 Multi-frac mandrel 
                   
               
               
                 175 
                 Customer Thread 
                   
               
               
                 215A 
                 Outer End Cap 
                   
               
               
                 215B 
                 Outer End Cap 
                 Opposite 
               
               
                 220 
                 Screen Off Port 
                   
               
               
                 225 
                 Screen Cover Ring 
                   
               
               
                 230 
                 Sliding Screen Valve 
                   
               
               
                 237 
                 Seats 
                 Locking rib member/cage seats in  
               
               
                   
                   
                 Screen Sliding Valve (design II),  
               
               
                   
                   
                 close to Screen 
               
               
                 238 
                 Seats 
                 Locking rib member/cage seats in  
               
               
                   
                   
                 Screen Sliding Valve (design II),  
               
               
                   
                   
                 close to Screen Sliding Valve Slot 
               
               
                 240 
                 Screen Open Sleeve 
                   
               
               
                 241 
                 Recess 
                 Recess in Open Sleeve Close to 
               
               
                   
                   
                 member 215A Design II 
               
               
                 242 
                 Recess 
                 Recess in Open Sleeve Close to  
               
               
                   
                   
                 member 215B Design II 
               
               
                 245 
                 Screen Rib member 
                   
               
               
                 250 
                 Screen Locking  
                   
               
               
                   
                 Rib Cage 
                   
               
               
                 255A, B 
                 Slots 
                 Mandrel &amp; screen open sleeve 
               
               
                 256 
                 Slot 
                 Screen Sliding Valve Slot design II 
               
               
                 260 
                 Screen On Port 
                   
               
               
                 300 
                 Screen 
                   
               
               
                 500 
                 Extension 
               
               
                   
               
            
           
         
       
     
     Other variations and modifications will, of course, become apparent from a consideration of the structures and techniques hereinbefore described and depicted. Accordingly, it should be clearly understood that the present invention is not intended to be limited by the particular features and structures hereinbefore described and depicted in the accompanying drawings, but that the present invention is to be measured by the scope of the appended claims herein.