Abstract:
According to the present invention, the line downhole jarring tool is a downhole tool for manipulating a work string which is easily configured to deliver a specific amount of force to the work string in a small and simple apparatus.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to downhole fishing and drilling operations, or removing obstructions to a drilling line when such a line becomes lodged or otherwise stuck in a well bore. Consequences of failure to remove the obstruction can be failure of the well to produce at all or in part, also, current methods of removing obstructions can result in failure to loosen the work string, both of which result in having to relocate the drilling operation, which necessarily involves lost time and money.  
           [0002]    This problem can be overcome, as it is now, by various devices which exert pressure or mechanical energy on the work string in an attempt to dislodge it. These tools are generally large, complex and expensive, and many are not easily configured to apply varying amounts of force to the work string, which can result in imprecise application of energy to the work string. This, in turn, can break or otherwise damage the work string, resulting in a requisite move of a project, or at the very least, lost time and energy in repairing the work string.  
           [0003]    The current invention fills the existing gap in technology by providing a relatively small, simple, adjustable tool which can be easily transported and implemented and be tailored to specific applications.  
           [0004]    It is known in the art to apply force to dislodge a work string, however the current devices in this field do not offer the unique combination of the small, simple and configurable characteristics inherent in the configuration presented herein.  
         OBJECTS OF THE INVENTION  
         [0005]    One object of this invention is to provide a configurable device which can apply specific amounts of pressure to a work string.  
           [0006]    Another object of the invention is to provide a device that is small and easily transported.  
           [0007]    Still another object of the invention is to provide a device that is able to shield an adjustment mechanism with a sleeve.  
           [0008]    Other objects and advantages of this invention shall become apparent from the ensuing descriptions of the invention.  
         SUMMARY OF THE INVENTION  
         [0009]    According to the present invention, the invention is a downhole tool for manipulating a work string which is easily configured to deliver a specific amount of force to the work string in a small and simple apparatus. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    The accompanying drawings illustrate an embodiment of this invention. However, it is to be understood that this embodiment is intended to be neither exhaustive, nor limiting of the invention. They are but examples of some of the forms in which the invention may be practiced.  
         [0011]    [0011]FIG. 1A shows a side view of the top half of the jarring tool, partially disassembled.  
         [0012]    [0012]FIG. 1B shows a side view of the bottom half of the jarring tool, partially disassembled.  
         [0013]    [0013]FIG. 2A shows a cutaway view of the top half of the jarring tool.  
         [0014]    [0014]FIG. 2B shows a cutaway view of the bottom half of the jarring tool.  
         [0015]    [0015]FIG. 3 shows a top view of the aligning collar. 
     
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS  
       [0016]    Without any intent to limit the scope of this invention, reference is made to the figures in describing the various embodiments of the invention. Referring to FIGS. 1 through 3, line downhole jarring tool  100  is pictured.  
         [0017]    Jarring tool  100  has a hammer mandrel  101  near the top end of jarring tool  100  which is formed with shaft  113  extending from the bottom end of hammer mandrel  101 . Shaft  113  can be formed such that a portion of shaft  113  has beveled sides, providing a flat surface that permits the shaft to be turned with a wrench, as well as forming a “keyed” relationship with the square opening  122  of retaining mandrel  102 &#39;s aligning collar  121 . This “keyed” relationship prevents relational torquing between shaft  113  and retaining mandrel  102 . This arrangement also precludes the need for aligning screws or other components, which detract from the simplicity and effectiveness of a tool.  
         [0018]    At the end of shaft  113 , shaft  113  forms a releasable bolt  103  which can be shaped conically as pictured, but could conceivably take various shapes, so long as releasable bolt  103  could be grasped and retained by another device, as explained in further detail below. The conical or “spear” shape of releasable bolt  103  also facilitates the re-entry of releasable bolt  103  into collet  105 , explained in greater detail below.  
         [0019]    Retaining mandrel  102  surrounds shaft  113 , and is usually threaded at one end to receive firing mandrel  104  which lies below it on jarring tool  100 . Firing mandrel  104  is generally cylindrical in shape, and having unlatching recess  117  along firing mandrel&#39;s  104  inner diameter, which is shaped to accommodate collet  105  as outlined below. Releasable bolt  103  also prevents shaft  113  from disengaging retaining mandrel  102  by virtue of releasable bolt&#39;s  103  size being larger than that of the edge  116  of retaining mandrel  102 .  
         [0020]    Collet  105  is attached to a kinetic energy shaft  118  toward the top end of jarring tool  100 . Collet  105  can have longitudinal slits  114  around its body, such that the overall diameter of collet  105  can be permitted to increase by radially expanding or separating slits  114 . The top end  115  of collet  105  should also be configured to be of larger diameter than the remainder of collet  105  to create a section that can enter either latching recess  117  or unlatching recess  123  of firing mandrel  104  permitting collet  105  to expand. This will be explained in greater detail below.  
         [0021]    Positioned between collet  105  and middle joint  107  is reloading mechanism  106 , generally a spring or spring-type device, which is held in place between collet  105  and middle joint  107 . It is positioned such that pressure is exerted upwardly on collet  105  and downwardly on middle joint  107 .  
         [0022]    Kinetic energy store  109  is positioned around kinetic energy shaft  118 , and can be any mechanical kinetic energy store, like a Belleville washer stack or a spring. Kinetic energy store  109  is usually a Belleville washer stack, which is generally an assemblage of concave washers stacked end to end such that resistance and linear energy is built up when the kinetic energy store  109  is compressed.  
         [0023]    At the base of kinetic energy shaft  118  is threaded or otherwise attached adjuster collar  110 . This is configured such that as adjuster collar  110  is threaded onto the bottom end of kinetic energy shaft  118 , such that as adjuster collar  110  is turned up the tool, compression is naturally increased on the kinetic energy store  109 , and thus upward resistance is increased.  
         [0024]    There is also in some exemplary forms of the invention threaded hole  119  drilled in kinetic energy shaft  118 , generally perpendicular to the lateral axis of jarring tool  100 . This provides for setscrew  120  which, when engaged in threaded hole  119 , prevents adjuster collar  110  from turning about its axis.  
         [0025]    Surrounding and encasing kinetic energy shaft  118  and kinetic energy store  109  is bottom mandrel  112 . Integrated in bottom mandrel  112  is adjuster collar guard  108 . Collar guard  108  has opening  111  which is essentially a window used to access adjuster collar  110 . Collar guard  108  is able to be turned about the axis of the tool, such that opening  111  only reveals a small portion of the surface beneath it. When properly actuated, however, opening  111  of collar guard  108  reveals adjuster collar  110  so that it may be accessed, and thus adjusted via various means. If collar guard  108  is then turned further, it effectively conceals adjuster collar  108 , thus preventing contaminants from entering, or from accidental adjustment of the components.  
         [0026]    Joining bottom mandrel  112  to firing mandrel  104  is middle joint  107 , which also houses a portion of kinetic energy shaft  118 .  
         [0027]    Each of the parts which lie along the central axis, if they are to be used in an application which requires electrical, data or other connections at the base of the tool can have a bore drilled parallel to this axis to permit runs of electrical or other wire through the center of jarring tool  100 . In such an application, parts along the center portion of the tool, such as shaft  113 , releasable bolt  103 , hammer mandrel  101 , collet  105  and kinetic energy shaft  118  have a bore in the center of them, permitting a wire or other ductile compound to be threaded through them, and thus, the entire tool.  
         [0028]    In operation, line downhole jarring tool  100  will be attached on its top and bottom ends to the work string. Jarring tool  100  will be likely initially “set,” whereby releasable bolt  103  is inserted into the center of collet  105 . This “setting” procedure is accomplished by moving shaft  113 , and thus bolt  103 , toward the bottom end of jarring tool  100 . Bolt will press against collet  105 , pushing it down whereby the top  115  of collet  105  will enter latching recess  117 , and bolt  103  will enter collet  105 . In this way, bolt  103  becomes mechanically coupled with collet  105 , and is ready for the impact stroke of jarring tool  100 .  
         [0029]    Adjuster collar guard  108  will be rotated about the axis of jarring tool  100  so that opening  111  will permit access to setscrew  120 , such that setscrew  120  may be removed, in turn permitting adjuster collar  110  to be threaded up or down, providing a corresponding increase or decrease in the tension stored in kinetic energy store  109 . In an exemplary embodiment, each full turn of adjuster collar  110  will raise or lower the pressure stored in kinetic energy store  109  by one hundred (100) pounds. Setscrew  120  can then be replaced, effectively locking adjuster collar  110  in place. Adjuster collar guard  108  can then be rotated back around to re-conceal setscrew  120  and related parts of adjuster collar  110 . Naturally, the setting need not be one hundred pounds, but is helpful to the operator to be in whole number increments, as to provide easy administration of pressure changes.  
         [0030]    When an obstruction is encountered, or the drill string otherwise needs to be loosened, force will be applied to jarring tool  100 , drawing back on the end of jarring tool  100 . When this force is applied to hammer mandrel  101 , shaft  113  is also drawn upward by virtue of its mechanical connection to hammer mandrel  101 . Releasable bolt  103  will similarly be drawn back, and move with it collet  105  and thus kinetic energy shaft  118 .  
         [0031]    As the force is applied, kinetic energy will continue to build as a result of the compression of kinetic energy store  109  under the force applied to hammer mandrel  101 . As this force increases, hammer mandrel  101 , shaft  113 , releasable bolt  103 , collet  105 , and kinetic energy shaft  118  all move toward the top end of jarring tool  100  until collet&#39;s  105  top end  115  slides into unlatching recess  117 , at which point longitudinal slits  114  expand, and releasable bolt  103  is released.  
         [0032]    As a result of this, the full store of kinetic energy in kinetic energy store  109  is exerted up and away, such that releasable bolt  103  travels quickly up within retaining mandrel  102  until it strikes edge  116  of retaining mandrel  102 , delivering the upward stroke, which, by design, helps to loosen the work string.  
         [0033]    At this time, the previous force exerted upon tool should be reversed, mechanically or otherwise, such that releasable bolt  103  will be inserted back into collet  105 . As bolt  103  is inserted into collet  105 , collet  105  is pushed back beyond unlatching recess  117  such that slits  114  are compressed, once again holding and retaining releasable bolt  103  within the confines of collet  105 . This cycle is thus repeated to achieve the desired hammering effect to loosen or otherwise manipulate the work string.  
         [0034]    Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims.