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CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    This is a continuation-in-part of co-pending U.S. patent application Ser. No. 09/437,871, filed Nov. 10, 1999, which is incorporated herein by reference.  
           [0002]    Provisional Patent Application Ser. No. 60/110,232, filed Nov. 30, 1998, is hereby incorporated herein by reference thereto.  
         STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0003]    Not applicable  
         REFERENCE TO A “MICROFICHE APPENDIX” 
         [0004]    Not applicable  
         BACKGROUND OF THE INVENTION  
         [0005]    1. Field of the Invention  
           [0006]    The apparatus of the present invention relates to jarring tools used in downhole drilling. More particularly, the present invention relates to an improved apparatus for jarring stuck tools, including pipe, downhole and a method of achieving same.  
           [0007]    2. General Background of the Invention  
           [0008]    In the art of drilling wells for recovery of hydrocarbons, the process incorporates a drill string which comprises a plurality of threaded tubular members such as drill pipe being approximately  30  foot each in length, the drill pipe threaded end to end which is then used to rotate the drill bit either from the surface or through the use of a drill motor which would rotate the bit without the rotation of the drill pipe itself. Often times during that process, the drill string will become lodged at a certain point along its length within the borehole.  
           [0009]    In the efforts to dislodge the drill pipe or other tools lodged downhole, a type of tool known as a jarring tool would be used in such an attempt. In the current state of the art, jarring tools as they currently utilize may be used to either jar the stuck or the lodged portion of pipe either in the up or down direction, depending on the makeup of the tool. In most cases, it would be more desirable to jar down on the pipe than to jar up. The reason for this is that drill pipe will usually get lodged when it is being pulled up as opposed to being moved downward, so jarring downward will more likely free the pipe. In such a case, the pipe is probably wedged against an obstruction caused by the upper movement of the pipe, and jarring upward may tend to wedge the debris around the section of pipe even tighter.  
           [0010]    Methods of downward jarring which are currently used in the art includes applying compression on the drill string to which a down jar has been attached, whereby the jar releases at a pre-set load, allowing the hammer of the jar to freely travel a short distance impacting the anvil of the tool, delivering a downward blow. The effectiveness of this method has limitations, due to compressional buckling of the drill string, as well as drag. Therefore, it is often difficult to achieve a large downhole jarring force in a vertical well, and the problem is exacerbated in the horizontal portion of a directional drilling operation. A jar in the upward direction can be attached to the top of the stuck pipe or tool, and the jar can be pulled upward until it is tripped. While this type of jarring can produce more force than downward jarring, it is typically in the wrong direction for most instances of stuck pipe. Certain patents have been obtained which address the method of jarring pipe loose from a borehole, and these will be provided in the prior art statement submitted herewith.  
         BRIEF SUMMARY OF THE INVENTION  
         [0011]    The apparatus of the present invention solves the problems in the art in a simple and straight forward manner. What is provided is an apparatus for jarring a portion of drill string lodged within a borehole, by jarring downward using tension versus compression. The apparatus would include a first member for attaching a first lower end of the apparatus to the upper end of the lodged tool or pipe through a threadable attachment; there would then be provided a second member for attaching a second end of the apparatus to a drill string on its upper end portion; there is further provided a third anvil or hammer member which is triggered by a spring having stored compressional force transferred by tension from the drill string to the apparatus when the drill string is pulled upward. There is also provided an actuator for rapidly releasing the tension force provided by the spring downward onto the stuck pipe in order to provide an impacting, downward force onto the pipe in an effort to dislodge the pipe. There is further provided a slow release mechanism for slowly releasing the tension force stored by the spring.  
           [0012]    Therefore, it is the principal object of the present invention to provide a tool for dislodging drill pipe down a borehole, which provides for a downward jarring on the stuck pipe or tool to facilitate dislodging of same;  
           [0013]    It is another principal object of the present invention to provide an apparatus for dislodging pipe or tools from a borehole by imparting a downward force, yet disallowing the weight of the hammer member from imparting additional, undesirable force on the surface mechanisms; It is a further object of the present invention to provide a jarring tool which has an internal mechanism for regulating the amount of force that is imparted onto the stuck object lodged within the borehole, yet provides for sufficient force to dislodge the pipe or tool within the borehole;  
           [0014]    It is a further object of the present invention to provide a method of dislodging tools stuck down a borehole which includes providing a tool having a first portion secured to the lodged tool, a second portion secured to the tubing above the tool, and a third portion defining a means for imparting jarring force against the stuck tool, while moving independently of the second portion to prevent undesired force on the elements above the tool.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein:  
         [0016]    [0016]FIG. 1 illustrates an overall outer view of the preferred embodiment of the apparatus of the present invention as it would be attached to drill pipe above and the stuck pipe or object below the apparatus;  
         [0017]    [0017]FIG. 2 illustrates an outer view of the apparatus as seen in FIG. 1 moving into the cocked position for firing;  
         [0018]    [0018]FIG. 3 illustrates an outer view of the apparatus in FIG. 1 fully cocked and ready to be fired in the bore hole;  
         [0019]    [0019]FIGS. 4 and 5 illustrate views of the preferred embodiment of the apparatus of the present invention as it is fired to impart downward force on the drill pipe lodged in a borehole;  
         [0020]    [0020]FIG. 6A illustrates an exploded partial view of the three members of the apparatus as they relate to one another; while  
         [0021]    [0021]FIG. 6B illustrates a partial cut away view of the jarring lower portion of the apparatus as it is being moved into the firing position,  
         [0022]    [0022]FIG. 7 illustrates a partial cut away view of the lower jarring portion of the apparatus of the present invention as it is ready to be fired;  
         [0023]    [0023]FIG. 8 illustrates a partial cut away view of the lower jarring portion of the apparatus of the present invention at the point that the apparatus is fired;  
         [0024]    [0024]FIGS. 9A and 9B illustrate views of the latching means used in the apparatus of the present invention;  
         [0025]    [0025]FIG. 10 illustrates a partial view of the internal cut away provided in the tension member of the present invention;  
         [0026]    [0026]FIG. 11A illustrates a cross section view of the secondary metering system used in the jarring mechanism working in conjunction with the fluid reservoir in the present invention, while FIGS. 11B and 11C illustrate the drill collars and tension tube utilized in the present invention; and  
         [0027]    [0027]FIGS. 12 through 14 illustrate views of an additional embodiment of the apparatus of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0028]    [0028]FIGS. 1 through 11C illustrate the first preferred embodiment of the present invention by the numeral  10 , as it would generally appear undertaking the process of dislodging a section of pipe or tools from the borehole. It should be noted that in general, apparatus  10  comprises three principal components. The first component comprises an upper section or member  12  secured to tubing, such as a drill pipe, coil tubing, or wireline, depending on the type of tool lodged downhole. There is provided a second lower member  16  secured to the tool or drill pipe lodged downhole, and a third “jarring” member  27 , comprising the hammer portion of the apparatus, which when fired, imparts downward force, striking the lower member  16  secured to the stuck tool or pipe.  
         [0029]    Turning first to FIG. 1, there is illustrated apparatus  10  secured at the upper portion  12  to a section of drill pipe  14  and at it&#39;s lower portion  16  to a tool or a portion of drill pipe  18  which has become lodged down the borehole by formation  20 . As further illustrated, the third “jarring member”  27  of apparatus  10  would further comprise a plurality, or preferably three drill collars  22 ,  24 ,  26 , in succession, in order to provide the requisite amount of mass to the “jarring” member  27  of the apparatus when the jarring takes place, so as to free the stuck pipe  18 .  
         [0030]    In FIG. 2, there is illustrated a portion of the upper portion  12  which includes an actuator sub  30 , including the tension tube  34 , which is secured to the upper portion of drill pipe  14  through the upper attachment portion  32  of upper portion  12 . The upper attachment portion  32  is secured to the tension tube portion  34  which would be pulled upward to compress an internal spring (not illustrated), and to set the firing mechanism so that the jarring portion  27  of the apparatus is locked in place ready to fire as seen in FIG. 3. Upon reaching a certain point of travel, the drill pipe  14  would be lowered as seen in FIG. 4, the jarring unit  27  would be fired, and the internal spring would expand rapidly forcing the hammer and connected drill collars  22 ,  24 ,  26  to impact the shoulder  38  of the jarring unit  27  against shoulder  40  of upper portion  42  of the lower portion  16  of tool  10 , as seen in FIG. 5, which in turn would jar the stuck tool or pipe  18 . This would be repeated until the tool is free. FIGS. 1 through 5 illustrate a general outer views of the operation of the apparatus  10 , while FIG. 6A illustrates the relationship of the three members of the apparatus, namely the upper member  12 , the lower member  16 , and the jarring member  27 , as they slidably engage into one another to form the composite apparatus. This interrelationship will be explained for fully, through FIGS. 6B through 11C which illustrate the details of the apparatus in its operation.  
         [0031]    [0031]FIG. 6B illustrates a partial cutaway view of jarring member  27  of the apparatus of the present invention moveable within the lower portion  16  secured to a lodged tool  18 . As illustrated, the jarring member  27 , includes a tension tube  34 . The hammer portion of the tool has an upper head portion  52  moveable within the jarring member  27  and would be slidably engaged within outer body  56  of lower attachment portion  16 . Hammer sub  54  would terminate at a flanged collar connector  58 , having an internal shoulder  60 , with an o-ring  62  for sealing the space between shoulder  60  and tension tube  34 . Below the collar connector  58  there is provided the cylindrical body  64  which terminates in an outer flange  66  for supporting the lower end of spring means  68  as illustrated. For purposes of construction, spring means  68  would preferably comprise a belleville spring, of the type known in the industry, or may comprise a fluid or hydraulic spring means. The inner face of the lower end of cylindrical body  64  would include a continuous concavity  70  around its inner face so as to accommodate the latch means  72  as seen in the figures, and as will be discussed further. As seen further in the FIG. 6B, the tension tube  34  terminates in a flanged collar portion  74  to raise and cock the hydraulic piston  76 . As illustrated in FIG. 6B, the latch means  72  is engaged within the concavity  70  around the inner face of the body  64 . When upward force is placed upon the tension tube  34 , by pulling on the upper tubing, the flanged collar portion  74 , which has engaged the lower end  77  of hydraulic piston  76 , begins to lift the cylindrical body  64 , which in turn compresses the spring  68 .  
         [0032]    Turning now to the lower portion of the jarring portion  27  there is provided a hydraulic means for sustaining the compressional energy now stored by spring  68 , to allow the tension to be to be lowered to fire the mechanism. As illustrated in FIG. 7, there is provided a hydraulic reservoir  78  which is formed between a first upper flanged collar  80 , and a second lower flanged collar  82 , in the wall of the outer body  56  of the jarring member  27 . As seen in FIGS. 7 and 8, the reservoir  78  contains a quantity of hydraulic fluid  81 , which is placed in the reservoir via access screws  83 , allowing access into reservoir  78 . It should be noted that the inner surfaces of each flanged collar  80 ,  82  is provided with an o-ring  85  so as to maintain hydraulic fluid  81  within the reservoir during operation of the tool. The piston  76  would include a check valve portion  84 , having a one way check valve  86 , so that as the piston  76  moved upward or downward, the check valve  86  positioned on a flanged collar  87  would allow the fluid to travel between those points above and below the flanged collar  87  so the piston may move upward rapidly but downward movement is retarded due to the metering action of the piston.  
         [0033]    In FIG. 6B, the piston  76  has been raised to a point where spring  68  is fully compressed and the tool is ready to fire. As seen in FIG. 7, the tension tube is lowered where upon the latch means  72  reaching the conical groove  90  in the wall of tension tube  34 , the latch means  72  disengages from conical groove  70  in the wall of tension tube actuator  54 , and moves into conical groove  90  in the wall of tension tube  34 . When this occurs, spring  68  is allowed to expand, and together with the mass provided by drill collars  22 ,  24 ,  26 , provides significant downward force on the jarring member  27 , so that the head  52  makes a substantial impact on the upper end of outer body  56 , which imparts a downward jar to the stuck drill pipe  18 . It is important to note that because of the three member configuration of the apparatus, the tension tube  34  allows free movement of the mass of the three drill collars  22 ,  24 ,  26 , attached to the actuator portion  54  so that when the jarring function of the tool is undertaken as explained above, the drill string is isolated from potential damage that would occur if the upper tubing was directly attached to the jarring member  27 . Furthermore, drag forces are minimized on the jarring system because of its independent movement.  
         [0034]    [0034]FIGS. 9A through 9C illustrate the latch mechanism  72  in its component parts. As seen if FIG. 9A, there is illustrated the latch means  72  positioned atop the piston body  76 . There is also illustrated the concavity or conical groove  70  in body  56 , in which the latch  72  is positioned. In this position, the tool is cocked and unfired, as seen in FIG. 6B. FIG. 10 illustrates the groove  90  which is formed completely around the wall of tension tube  34 , into which latch  72  would slide to trigger the apparatus, as discussed earlier in FIG. 8.  
         [0035]    For understanding the relationship between latch means  72  and the piston body  76 , reference is made to FIG. 9B. As illustrated, the latch means  72  comprises four segments  72 A through  72 D which include a quarter-round an upright body portion  77  and a lower dovetail oval-shaped portion  79  which would engage into a dovetail oval-shaped opening  81  in piston  76 . Therefore, when each of the segments  72 A through  72 D are engaged in openings  81 , the latch means  72  is formed in the circular configuration for operating in the tool. This engagement as provided, allows the movement of the latch member  72  from the position engaged in groove or concavity  70  while the tool is cocked, to the position in groove or concavity  90 , when the tool is fired. Again, FIG. 10 illustrates the groove  90  formed in the wall of the tension tube  34  which receives the four components  72 A through  72 D when the tool is fired.  
         [0036]    Although some discussion was made earlier regarding the hydraulic fluid reservoir  78 , its function as a primary metering device has not been fully discussed. Returning first to FIG. 7, which illustrates the tool cocked and ready for firing. In the event that a driller should decide not to fire the apparatus after the apparatus is in position for firing as illustrated in FIG. 7, or the driller would make a decision to raise the entire drill string due to freeing of the pipe, the spring member  68  together with the hydraulic piston  76 , with the hydraulic flange  77  and the latch mechanism  72  will slowly move downward and release the stored energy of the jarring mechanism within a designed period of time. The further reduction of recessed area  90  at point  94  would allow the driller to lower the drill string to fire the jar immediately with minimum loss of the spring member  68  compression due to the varying hydraulic bleed of the hydraulic metering system in place. As was stated earlier, as the actuator is lowered to its length, in the stroke, the compression in the spring  68  is maintained by the hydraulic pressure within hydraulic fluid reservoir  78 , by means of a one-way check valve  84 . When the machine opening  90  of the tension tube actuator  54  reaches the segmented latch mechanism  72 , the latch mechanism  72  is then forced out of the way of the hydraulic piston  76 , releasing the lower portion  42  of the tool  10  to impact the shoulder  40  of the jarring tool  52  at impact surface  38 .  
         [0037]    Therefore, if the tension tube actuator  34  is not lowered within a few minutes of the raising of the drill string, the hydraulic metering assembly will slowly uncock the spring  68  as the hydraulic fluid  81  within the reservoir  78  moves slowly from the lower portion to the upper portion of the reservoir. In this manner, the tension in the spring  68  will be released long before the jarring tool  52  reaches the surface eliminating a potential safety hazard.  
         [0038]    After the tool has either fired or moved into the position of having been uncocked as described above, the tool then must be “re-cocked” in order to undertake an additional firing. For example, in FIG. 8 there is illustrated the tool after the hammer  52  has fired and the latch means has moved from the cocked position set within opening  70 , to the firing position after it is moved into opening  90 . Of course, after the tool has fired, it is necessary to recock the tool into the position as seen in FIG. 7. therefore, the tension tube  34  must be lowered into position so that the latch  72  would reengaged into opening  70 . In order to accomplish this, the hydraulic fluid  81  must be re-bled back into the lower portion of the reservoir  78 . Since the return of the fluid in that manner would result in the tool being recocked very slowly, reference is made to FIG. 11A, where there is illustrated a secondary metering component  91 , which is an opening formed in the wall of tension tube actuator portion  54  so that the hydraulic fluid may flow into the metering component  91  and allow the tool to be recocked rather quickly rather than having to allow for the fluid to completely flow to the lower portion of the reservoir  78 . After this is accomplished, the tool is ready to be refired as seen in FIG. 7.  
         [0039]    The first embodiment of the present invention can provide significantly more compressive force to jar with, as tension is easily applied to the apparatus, whereas in conventional jars, precompression is difficult to achieve due to the buckling of the drill string, especially in horizontal directional drilling operations. With the present invention, one can also jar over a much longer stroke than existing jars due to the fact that the tool decouples the drill string from the jarring apparatus via the tube member  34 . Instead of a 4 to 6 inch jarring stroke, a massive jarring stroke of from 3-5 feet can be obtained with the apparatus of the present invention. The result in order of magnitude, is approximately ten fold, of an increase of inline jarring energy. In this invention, the jarring mass of the three interconnected drill collars spans a total of 95 feet. In existing art, the typical drill string must move over several thousands of feet to effect a conventional jarring system.  
         [0040]    [0040]FIGS. 12 through 14 illustrate a second principal embodiment of the apparatus of the present invention. As is illustrated in the figures, tool  101  houses a mandrel  102  including a threaded connection  130  at the upper end of the mandrel  102  for threadably engaging to an upper portion of pipe or the like. Mandrel  102  includes a hammer portion  103 , which further comprises an external spline  104  for engaging an internal spline  105  formed on tool  101 , for allowing mandrel  102  to move upward and downward relative to the tool  101  and transmit torque through the outer housing of the tool  101 . Threaded connection  106  provides a means of assembly between the upper portion of mandrel  102  and the next portion of the mandrel.  
         [0041]    There is further provided a spring means  107 , which may be a coiled or other type of spring, or comprised of a compressible gas or liquid. Spring means  107  is housed between the outer wall of mandrel  102  and within an internal cylinder  108  of the tool  101  and engaged on its lower end by a piston  113  of the mandrel  102 . The upper end of spring means  107  is engaged or contained on a shoulder  132 . Connection  115  provides assembly joint of the lower end of cylinder  108 .  
         [0042]    There is further provided a seal  114 , which maintains spring means  107  isolated from the fluid volumes below it. This seal  114  allows spring means  107  to travel or, in the case of a compressible gas or liquid be compressed between a compressed state, as a high pressure means, to its released state as a low pressure means, while contained within cylinder  108  of tool  101 . Cylinder  108  is sealed off from the metering fluid  119  by seal  117 . The metering fluid  119  comprises a first metering volume  120  and release volume  121 . Triggering shoulder  129  separates the metering volume  120  from the release volume  121 . Shoulder  123  provides a slow metering means for metering volume  120  and also includes a one way valve  123   a  which allows fluid to travel below the shoulder  123 , as the mandrel  102  is pulled upward to allow for rapid cocking of the tool. Joint  124  provides connection for assembly, while filler port  125  provides a means for filling of metering fluid  119 , into volumes  120  and  121 . Cap  126  seals the filler port  125  after the metering fluid is in the tool  101 .  
         [0043]    Turning now to FIG. 13, the tool  101  would be cocked from its first position, as seen in FIG. 12, by an upward pull on mandrel  102  compressing and energizing spring means  107  as well as displacing shoulder  123  from the release volume  121  into the smaller area of the metering volume  120 . Upon release of the upward pull of mandrel  102 , because of the small area of the metering volume  120 , and the one-way valve  123   a , the mandrel travels slowly downward, in the direction of arrow  127 , to allow time for the operator to place the tool  101  in compression, thereby allowing subsequent firing of the tool without imparting a load on the drill string attached at the upper end to mandrel  102 .  
         [0044]    In FIG. 14, shoulder  123  has now travelled past trigger point shoulder  122 , allowing piston  123  to move freely through release volume  121 , and thus firing the tool. This motion is caused by high pressure energy provided by spring means  107 , which was compressed into a high pressure state by the upward pull of mandrel  102  by the attached drillstring.  
         [0045]    The downward jarring is accomplished by contact between hammer member  103  on mandrel  102  making a jarring contact with anvil  105 a, on the upper end of tool  101 , as shown in FIG. 1.  
         [0046]    The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.

Summary:
An apparatus for dislodging stuck tools downhole, which includes a tool body; a mandrel moveable within the tool body; a spring member for allowing the mandrel to move with jarring force within the tool body when actuated; actuating fluid allowing the mandrel to travel a portion of the distance in a controlled manner, and at a predetermined point, accelerate its travel to provide a jarring force against the tool body; wherein the actuating fluid includes a first and second volumes of fluid through which a portion of the mandrel travels; the first volume providing controlled travel, and the second volume allowing accelerated travel of the mandrel.