Downhole intelligent impact jar and method for use
An intelligent downhole impact jar device is described that is able to sense well bore angle or deviation and alter the effective jar impact load based upon the sensed information. The impact jar device includes a jarring portion for creating jarring impacts within a wellbore toolstring. The jarring portion is adjustable so that jarring forces of various levels can be produced. The jarring portion is adjusted in response to sensed wellbore conditions, such as the angle of deviation of the surrounding wellbore.
1. An impact jar device incorporated within a toolstring in a wellbore, the jar device comprising:
a jarring portion for imparting jarring impacts to the toolstring, the jarring portion being adjustable to create jars of various force levels;
a sensor for determining an angle of deviation of the surrounding wellbore from vertical and providing a signal representative of such condition; and
a controller to receive the signal from the sensor and, in response, adjust the force level of the jarring impact provided by the jarring portion to match the wellbore condition.
2. The impact jar device of claim 1 wherein the jarring portion comprises:
a striking surface;
an impact anvil for impacting the striking surface to create a jarring impact; and
a release assembly for retaining and releasing the impact anvil to strike the striking surface to create a jarring impact.
3. The impact jar device of claim 2 wherein the release assembly comprises:
a spring housing;
a release member associated with the spring housing for releasably retaining the impact anvil;
a compressible spring disposed within the spring housing; and
a spring compressing member to compress the spring and pretension the release member, the spring compressing member comprising a telescoping shaft having first and second shaft members that are telescopically moveable with respect to one another to adjust the force level of jarring impact provided by the jarring portion.
4. The impact jar device of claim 3 wherein:
the first and second shaft members are telescopically moveable by rotation of the first and second shaft members with respect to one another; and
the controller adjusts the force level of the jarring impact by rotating the first shaft member with respect to the second shaft member.
5. The impact jar device of claim 1 wherein the sensor comprises an inclinometer.
6. The impact jar device of claim 1 wherein the controller determines a loss of impact force from the angle of deviation and adjusts the force level of jarring impact based upon that loss.
7. An impact jar device incorporated within a toolstring in a wellbore, the jar device comprising:
a jarring portion for imparting jarring impacts to the toolstring, the jarring portion being adjustable to crate jars of various force levels;
an inclinometer for determining an angle of deviation from vertical of the surrounding wellbore and providing a signal representative of such condition; and
a controller to receive the signal from the sensor and, in response, adjust the force level of the jarring impact provided by the jarring portion to match the angle of deviation.
8. The impact jar device of claim 7 wherein the jarring portion comprises:
a striking surface;
an impact anvil for impacting the striking surface to create a jarring impact; and
a release assembly for retaining and releasing the impact anvil to strike the striking surface to create a jarring impact.
9. The impact jar device of claim 8 wherein the release assembly comprises:
a spring housing;
a release member associated with the spring housing for releasably retaining the impact anvil;
a compressible spring disposed within the spring housing; and
a spring compressing member to compress the spring and pretension the release member, the spring compressing member comprising a telescoping shaft having first and second shaft members that are telescopically moveable with respect to one another to adjust the force level of jarring impact provided by the jarring portion.
10. The impact jar device of claim 9 wherein:
the first and second shaft members are telescopically moveable by rotation of the first and second shaft members with respect to one another; and
the controller adjusts the force level of the jarring impact by rotating the first shaft member with respect to the second shaft member.
11. The impact jar device of claim 7 wherein the controller determines a loss of impact force from the angle of deviation and adjusts the force level of jarring impact based upon that loss.
12. A method of imparting an adjustable jarring impact to a toolstring within a wellbore comprising the steps of:
a) incorporating a jarring device into a wellbore toolstring, the jarring device having a jarring portion for creating jarring impacts within the toolstring, the jarring portion being adjustable to create jars of various force levels;
b) disposing the jarring device and toolstring into a wellbore;
c) determining an angle of deviation from vertical of the tool within the wellbore;
d) calculating an adjustment to the jarring portion based upon the determined angle of deviation;
e) thereafter adjusting the jarring portion so that the jarring portion will provide a jar of a predetermined level of force; and
f) actuating the jarring portion to create a jarring impact.