Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B31/00—Fishing for or freeing objects in boreholes or wells
  • E21B31/107—Fishing for or freeing objects in boreholes or wells using impact means for releasing stuck parts, e.g. jars

Definitions

• the present invention relates to a mechanical trigger arrangement for the repeated mechanical triggering of various types of downhole equipment, such as the repeated triggering of impact hammers, for example, for which a predetermined resistance against movement is needed in order to tension a tensioning mechanism, such as a spring mechanism, also referred to as an accelerator, for the purpose of storing potential energy that may be subsequently released and converted into kinetic energy.
• a tensioning mechanism such as a spring mechanism, also referred to as an accelerator
• impact hammers are used.
• One type of impact hammers is tensioned using a wireline, wherein the alternate pulling and slackening of the wireline will cause a desired number of repeated blows against the stuck equipment to which the impact hammer has been attached.
• impact hammers consist of an inner string section and an outer pipe section being telescopically connected so as to allow for a relative axial movement between the sections.
• the string section and pipe section meet in an impact, so that the relative kinetic energy between the sections is transferred in the form of impact energy.
• a trigger mechanism will ensure that the relative movement of the inner string section and outer pipe section is delayed or reduced by applying an axial force until the tensioning has reached a certain level.
• potential energy may be stored in a suitable spring, for example.
• the stored energy is converted into kinetic energy by the initiation of the relative movement between the inner string section and outer pipe section.
• the trigger mechanism of a mechanical impact hammer typically includes a spring element resisting the movement of the inner string section relative to the outer pipe section.
• the spring element is connected to a locking means that is released at a predetermined position, which position is reached by forcing a sufficient compression of the spring element.
• the locking means is released and the stored energy will be converted into kinetic energy, after which the sections ultimately meet in an impact.
• US 3,685,598 relates to an impact hammer that may adjusted to a desired release force.
• the impact hammer of US 3,685,598 includes a mandrel being telescopi- i5 cally arranged in a housing, with locking means being provided retaining the mandrel in a fixed position relative to the housing until a longitudinal force of sufficient magnitude is applied to the impact hammer.
• the longitudinal force is counteracted by way of an elastic element, the resisting force of which is a function of the longitudinal movement required to release the locking means.
• 2o also includes adjustable elements that may be used for adjusting the amount of longitudinal movement of the elastic elements required to release the locking means and hence trigger the impact hammer.
• the present invention provides a mechanical trigger arrangement, which, as compared to corresponding hydraulic arrangements, makes a highly operationally reliable and economically advantageous alternative, as the mechanical trigger arrangement of the present invention provides a simple and robust design being comprised of only a few moveable parts.
• the arrangement according to the present invention results in a simplified manufacturing process, making the trigger arrangement an economically, alternative product that may be used in various applications for which economical factors are essential.
• the present invention also allows for downhole operations involving the use of very high suspended loads, as the release force of the mechanical trigger arrangement may be adjusted to the necessary level, i.e. the mechanical trigger arrangement will not be released without the existence of a predetermined excessive load in addition to the suspended load.
• the arrangement according to the present invention has the advantage over the conventional trigger arrangements that it may be adjusted to release at a predetermined trigger force with a much greater accuracy as the trigger force will depend directly on a spring device being compressed and released, without any significant influence from conditions like friction and wear.
• the present invention provides a mechanical trigger arrangement differing significantly from the conventional solutions and offering significant advantages with respect to operation, efficiency, reliability, and economy.
• the mechanical trigger arrangement according to the present invention is configured for having a resistance against an axial movement of a protruding string section for applied forces up to a predetermined magnitude, beyond which the resist- ance against further movement is very small.
• Fig. 1 shows the arrangement in the start position thereof
• Fig. 2 shows the arrangement in the maximum tensioned position thereof
• Fig. 3 shows the arrangement in the released position thereof
• Fig. 4 shows the arrangement in a return position thereof
• Figs. 5 and 6 show the string section of the arrangement in different angle views
• Fig. 7 shows the string section of figs. 5 and 6, as seen in an end view
• Fig. 8 shows section A of fig. 5
• Figs. 9-11 show an end piece comprising a beak in different angle views
• Figs. 12-15 show a rotary sleeve in different angle views.
• the mechanical trigger arrangement according to the present invention is configured to force a relative rotary movement between the two moveable parts (string section 1 and rotary sleeve 7) of the trigger arrangement as a premise for the axial movement.
• the rotary sleeve 7 is adapted for engaging one of the turning faces 1', 2' of string section 1 , the position of turning faces 1 ', 2' being dependent on the axial position of rotary sleeve 7 relative to string section 1.
• the turning faces of string section 1 and the corresponding turning faces of rotary sleeve 7 have different slopes, with 1' and 1 " having an equivalent slope and 2' and 2" having an equivalent slope.
• Turning faces 1 ' and 1 " has the least slope. The purpose of these turning faces is to rotate the rotary sleeve to an unlocked position. The small slope ensures that a high magnitude force is developed.
• Turning faces 2' and 2" have a greater slope. The purpose of these turning faces is to have the residual tension of the coil spring rotate the sleeve back to the starting position to allow the mechanical trigger arrangement to be re-tensioned for the next triggering cycle.
• String section 1 is rotationally supported in an end piece 6 comprising a beak 8 in order to achieve a certain mutual starting orientation/position between the end piece 6, string section 1 , and rotary sleeve 7.
• a spring element 4 is disposed between string section 1 and end piece 6 in such a manner that the spring 4 is compressed by the axial movement of string section 1 relative to end piece 6.
• the tool is tensioned when string section 1 is pulled to the right.
• the amount of tensioning of the spring corresponds to the distance with which string section 1 is pulled relative to end piece 6, with turning face 1 ' of string section 1 and turning face 1" of rotary sleeve 7 causing rotary sleeve 7 to rotate relative to the beak 8 of end piece 6 (figs. 1 and 2) and ultimately snap into beak 8 as shown in fig. 3.
• String section 1 includes a 5 groove 10 ensuring that string section 1 and end piece 6 will not rotate relative to each other, as beak 8 extends into groove 10 (fig. 10)
• the pretension of spring 4 may be adjusted by way of a pretension pin 3 and a spring pretension ring 5. This may be achieved by displacing and locking pretension pin 3 and spring pretension ring 2 axially relative to string section 1.
• Pretension pin 3 extends into a suitable groove in string section 1. It is understood that 0 other types of pretension elements may also be used, such as a threaded rotat- able tensioning disk or a similar element, for example, that increases or reduces the pretension by rotating the disk or similar element up or down along string section 1.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• Engineering & Computer Science (AREA)
• Mining & Mineral Resources (AREA)
• Physics & Mathematics (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• Marine Sciences & Fisheries (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Earth Drilling (AREA)
• Percussive Tools And Related Accessories (AREA)
• Catching Or Destruction (AREA)
• Springs (AREA)

Applications Claiming Priority (2)

Publications (2)

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• 2006
  • 2006-07-13 NO NO20063252A patent/NO325507B1/no not_active IP Right Cessation
• 2007
  • 2007-07-09 CA CA002657609A patent/CA2657609A1/en not_active Abandoned
  • 2007-07-09 EP EP07793918.9A patent/EP2041390A4/de not_active Withdrawn
  • 2007-07-09 US US12/309,197 patent/US20090301745A1/en not_active Abandoned
  • 2007-07-09 WO PCT/NO2007/000266 patent/WO2008016308A1/en active Application Filing

Non-Patent Citations (1)

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