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US 9,790,756 B2Granted
Wireline down jar
OwnerKeith McNeillyinventor
Life of this patent
Estimating the term…
Abstract
A jar assembly for use downhole includes a housing, a piston assembly slidable within and selectively coupled to the housing, a mandrel assembly coupled on a lower end of the piston assembly, and an anvil coupled to an end of the mandrel assembly opposite the piston assembly. The jar assembly is deployed in a wellbore by a conveyance means that couples with the housing. A hydraulic circuit in the piston assembly activates a latch for decoupling the piston assembly from the housing; when decoupled, the housing slides downward and impacts the anvil to generate a jarring force. The jar assembly is re-cocked by raising it with the conveyance means.
Claims20
A jar assembly for use in a wellbore comprising:
- an annular housing;
- an elongated mandrel in selective telescoping relationship with the housing;
- an anvil coupled with an end of the mandrel and selectively coupled with a downhole tool;
- an annular cylinder slideably disposed within the housing:
- a fluid reservoir defined in the cylinder and containing a fluid;
- a piston comprising:
- a head portion slideably disposed in the fluid reservoir, and a body portion attached to the head portion, the body portion coupled with the mandrel and having a transition defining a change of diameter of the body portion;
- a downward facing shoulder on an inner surface of the housing;
- and
- a lug coupled with the cylinder that is radially moveable with respect to the cylinder and axially slideable along the transition, and that is in selective interfering contact with the shoulder when the lug is adjacent a larger diameter portion of the body, and is moved out of interfering contact with the shoulder when the lug is moved past the transition, so that when the mandrel is supported in the wellbore the housing slides axially downward into contact with the lug to transfer a force that urges the fluid through a passage formed in the piston head to a side of the piston head proximate the lug, that in turn urges the transition past the lug so the lug moves radially inward and out of interfering contact with the shoulder so that the housing slides axially downhole and into jarring contact with the anvil.
7 more elements
A jar assembly for use downhole comprising:
- an annular housing having an inner diameter with a downward facing shoulder;
- an elongated mandrel;
- an anvil mounted on an end of the mandrel;
- a cylinder axially moveable within the housing:
- a piston having a piston head slideably disposed in the cylinder and a piston body depending from the piston head, the piston body having a reduced diameter portion, a larger diameter portion, and a transition between the reduced and larger diameter portions;
- a lug slideably disposed in a radially oriented slot that is axially coupled with the cylinder, the lug having a radially outward end that is in selective interfering contact with the downward facing shoulder and a radially inward end in sliding contact with the piston body, so that when the housing is moved axially downhole and the downward facing shoulder is in contact with the radially outward end of the lug, a force is applied to the lug;
- and
- a means for transferring the force applied to the lug to a surface of the piston head proximate the piston body to slide the piston body so that the lug is adjacent the reduced diameter portion and moves radially inward out of interfering contact with the downward facing shoulder so that when the mandrel is supported in the wellbore, the housing slides axially downward into contact with the lug to transfer a force that urges the fluid through a passage formed in the piston head to a side of the piston head proximate the lug, so that the housing moves into jarring contact with the anvil.
5 more elements
A method of applying a jarring impact downhole comprising:
- a. lowering a jar assembly into a wellbore, the jar assembly comprising a piston comprising a piston head, and a piston body with a reduced diameter portion and a larger diameter portion, a mandrel rotatingly coupled to an end of the reduced diameter portion distal from the piston head, a housing axially moveable with respect to the mandrel, a downward facing shoulder on an inner surface of the housing, an anvil on an end of the mandrel;
- an annular cylinder inserted in housing, a fluid reservoir in the cylinder in which the piston head is axially reciprocatable, and a lug that is radially moveable having a radial outward end in selective interfering contact with the shoulder, and a radial inward end in sliding contact with the piston body:
- b. providing slack in the line supporting the jar assembly by positioning the jar assembly downhole so that the weight of the housing is supported by the mandrel;
- c. sliding the housing downhole so that the downward facing shoulder is in interfering contact with the lug and applies a force to the lug;
- d. urging the piston uphole in response to the step of transferring the force applied to the lug so that the lug is disposed adjacent to the reduced diameter portion of the piston body and moves radially inward and out of interfering contact with the downward facing shoulder so that when the mandrel is supported in the wellbore, the housing slides axially downward into contact with the lug to transfer a force that urges the fluid through a passage formed in the piston head to a side of the piston head proximate the lug;
- and
- e. sliding the housing downhole with respect to the mandrel and into jarring impact with the anvil.
4 more elements
Dependencies are inferred from the claim text.