Offshore staff
HOUSTON -- Logan Oil Tools has introduced a straight pull, up only, jarring tool, the Logan Superior Hydraulic Fishing Jar. It uses a special valve section to meter oil from one chamber of the piston to the other to allow controlled jarring action during a stuck fish recovery.
The operating chambers are sealed and isolated from each other to prevent contamination of the metering section and the well. During the downhole operation, jarring blow is infinitely adjustable without any rig floor movements necessary prior to the run.
The straight pull load applied by the operator controls the intensity of the jarring blow. Pull load is varied to change the blow. Since oil is not metered during re-cocking, only a very light load (enough to overcome friction) is required.
The light re-cocking load allows the operator to hit a rapid series of blows if needed to free a stuck fish. Logan Superior Hydraulic Fishing Jars are hydrostatically pressure balanced, and maximum inside diameters permit passage of wireline tools. Its large mandrel design makes it well suited for fishing, milling, and washover operations.
When maximum jarring impact and impulse are needed, particularly in shallow, deviated, or directional holes where acceleration and effectiveness of movement is diminished, a Logan Superior Energizer is run in conjunction with a Logan Superior Hydraulic Fishing Jar of corresponding size.
The energizer is essentially a fluid spring that stores energy when strain is applied to the fishing string. It offsets the loss of stretch or drag on the running string and provides a means to store required energy immediately above the drill collars and the fishing jar to increase the amount of impact energy. Use of an energizer also allows the use of fewer drill collars.
Stored energy is released from the energizer when strain is removed by the free stroke of the fishing jar, and the drill collars are accelerated upward until impact. The hydraulic fluid contained in the fishing jar cushions much of the jarring shock from the rebounding string after each stroke. This protects tools and the working string from damage.
Velocity and relative impact load of a blow is controlled by the amount of stretch in the running string (pull load) and the weight of the drill collars installed above the fishing jar. Variable load is controlled by applying a lighter or heavier pull on the working string.
Logan's energizer is safe to assemble since no high-pressure pre-loading is required.
2/15/2007
