초록 ▼

Setting mechanisms for downhole tools are described that take advantage of hydrostatic pressure in the wellbore which is harnessed to set a tool after exposure to well fluids for a given time or temperature defeats a lock and allows hydrostatic forces to trigger the setting of the tool. Alternative

Setting mechanisms for downhole tools are described that take advantage of hydrostatic pressure in the wellbore which is harnessed to set a tool after exposure to well fluids for a given time or temperature defeats a lock and allows hydrostatic forces to trigger the setting of the tool. Alternatively, some other biasing source is released to set the downhole tool after exposure to well fluids for a time or a temperature and time defeats a lock and allows the biasing source to set the tool. While applications to packers are preferred, other downhole tools can be set in his manner removing the need for an inner string, dropping a ball on a seat or pressurizing the wellbore to achieve the setting of the downhole tool.

대표청구항 ▼

We claim: 1. An apparatus for setting a downhole tool in existing well fluid, comprising: a mandrel comprising an actuating component assembly relatively moveable thereto for selective actuation of the downhole tool; a restraining member, having a longitudinal axis, said restraining member acting o

We claim: 1. An apparatus for setting a downhole tool in existing well fluid, comprising: a mandrel comprising an actuating component assembly relatively moveable thereto for selective actuation of the downhole tool; a restraining member, having a longitudinal axis, said restraining member acting on said actuating component assembly, said restraining member remaining operative for delivery of the downhole tool to near the position where said actuating component assembly will then be actuated by release of compressive loading acting on said actuating component assembly, and whereupon said delivery, a delay period is triggered that terminates with the release of said actuating component assembly by said restraining member by virtue of a developed inability of the restraining member to resist said compressive force which results in a collapse along said longitudinal axis of said restraining member without shear of said restraining member, responsive to exposure of said restraining member to said existing downhole fluid, for automatic setting of the downhole tool; said developed inability of said restraining member comprises weakening from at least one of temperature of the well fluids and duration of exposure to said existing well fluids; said weakening comprises dissolving said restraining member. 2. An apparatus for setting a downhole tool, comprising: a mandrel comprising an actuating component relatively moveable thereto for selective actuation of the downhole tool; a restraining member acting on said actuating component assembly, said restraining member remaining operative for delivery of the downhole tool to near the position where said actuating component assembly will then be actuated by defeat of said restraining member, and whereupon said delivery a delay period is triggered that terminates with the release of said actuating component assembly by said restraining member for automatic setting of the downhole tool; said restraining member begins to weaken from at least one of temperature of the well fluids and duration of exposure to well fluids; said actuating component assembly comprises a piston movable by hydrostatic pressure in the wellbore upon said weakening of said restraining member; said piston defines at least one sealed chamber at a pressure lower than the available hydrostatic pressure, whereupon weakening of said restraining member the volume of said chamber is reduced as said piston moves to set the downhole tool; said piston defines a second sealed chamber with a port and a valve selectively putting said second sealed chamber in fluid communication with available hydrostatic pressure, whereupon said weakening of said restraining member said port opens to move said piston. 3. The apparatus of claim 2, wherein: the volume of said second sealed chamber grows as said valve opens while the volume of said first chamber shrinks as a result of movement of said piston. 4. The apparatus of claim 2, wherein: said valve comprises a sleeve covering said port, said sleeve configured for end dimensions of differing sizes to create a net unbalanced force from available hydrostatic pressure; said restraining member preventing movement of said sleeve from said unbalanced force until said weakening. 5. The apparatus of claim 2, wherein: said valve comprises a sleeve covering said port; said sleeve further subjected to a stored force from an energy source operably connected thereto but incapable of shifting said sleeve until weakening of said restraining member. 6. The apparatus of claim 5, wherein: said energy source and said restraining member are disposed at opposed ends of said sleeve. 7. The apparatus of claim 5, wherein: said energy source comprises fluid pressure. 8. The apparatus of claim 5, wherein: said energy source comprises at least one spring. 9. The apparatus of claim 5, wherein: said energy source comprises an initially compressed resilient material. 10. The apparatus of claim 5, wherein: said energy source comprises a shape memory material that grows in one dimension as said restraining member is weakening. 11. The apparatus of claim 5, wherein: said energy source comprises foam. 12. An apparatus for setting a downhole tool in existing well fluid, comprising: a mandrel comprising an actuating component assembly relatively moveable thereto for selective actuation of the downhole tool; a restraining member, having a longitudinal axis, said restraining member acting on said actuating component assembly, said restraining member remaining operative for delivery of the downhole tool to near the position where said actuating component assembly will then be actuated by release of compressive loading acting on said actuating component assembly, and whereupon said delivery, a delay period is triggered that terminates with the release of said actuating component assembly by said restraining member by virtue of a developed inability of the restraining member to resist said compressive force which results in a collapse along said longitudinal axis of said restraining member without shear of said restraining member, responsive to exposure of said restraining member to said existing downhole fluid, for automatic setting of the downhole tool. 13. The apparatus of claim 12, wherein: said developed inability of said restraining member comprises weakening from at least one of temperature of the well fluids and duration of exposure to said existing well fluids. 14. The apparatus of claim 13, wherein: said weakening comprises structural failure of said restraining member. 15. The apparatus of claim 13, wherein: said weakening comprises a reduction in volume of said restraining member. 16. The apparatus of claim 13, wherein: said weakening comprises a shape memory material acting as said restraining member and reverting to a different shape. 17. The apparatus of claim 13, wherein: said actuating component assembly comprises a piston movable by hydrostatic pressure in the wellbore upon said weakening of said restraining member. 18. The apparatus of claim 17, wherein: said piston defines at least one sealed chamber at a pressure lower than the available hydrostatic pressure, whereupon weakening of said restraining member the volume of said chamber is reduced as said piston moves to set the downhole tool. 19. The apparatus of claim 18, wherein: said piston defines a second chamber wherein said restraining member is disposed such that said piston cannot move with respect to said mandrel until said weakening of said restraining member. 20. The apparatus of claim 19, wherein: said second chamber comprises an opening past said piston to allow well fluids to enter said chamber during run in.