Hydraulic fishing jar having tandem piston arrangement

In a hydraulic fishing jar adapted to be run into a well on a fishing string and connected to a fishing tool in the well bore:

• a. Inner and outer telescopically interengaged bodies;
• b. A plurality of diametrically defined pressure areas, each of said areas having upper and lower sealed ends;
• c. Tandem piston means immediate one of said upper and lower sealed ends of each of said pressure areas;
• d. Seal means carried by one of said inner and outer interengagable bodies and engagable by the other of said inner and outer interengagable bodies and defining one of the upper and lower sealed ends of said pressure areas;
• and
• e. Seal means between said piston means and one of said inner and outer telescopically interengaged bodies and defining one of the upper and lower sealed ends of said pressure ends.
• said fluid pressure areas being in fluid communication with one another and defining a chamber for receipt of lubricant therewithin.

In a hydraulic fishing jar adapted to be run into a well on a fishing string and connected to a fishing tool in the well bore:

• a. Inner and outer telescopically interengaged bodies;
• b. First diametrically defined pressure area having upper and lower sealed ends;
• c. First tandem piston means immediate one of said upper and lower sealed ends of said first pressure area;
• d. First seal means carried by one of said inner and outer interengagable bodies and engagable by the other of said inner and outer interengagable bodies and defining one of the upper and lower sealed ends of said first diametrically defined pressure area;
• e. Second seal means mounted on said first tandem piston means and defining the other of the upper and lower sealed ends of said first pressure area;
• f. Second diametrically defined pressure area having upper and lower sealed ends;
• g. Second tandem piston means mounted on one of said upper and lower sealed ends of said second pressure area;
• h. Third seal means carried by one of said inner and outer interengagable bodies and engagable by the other of said inner and outer interengagable bodies and defining one of the upper and lower sealed ends of said second pressure area;
• and
• i. Fourth seal means mounted on said second tandem piston means and defining the other of the upper and lower sealed ends of said second pressure area;
• said first and second pressure areas being in fluid commuication with one another, said first and second pressure areas defining a lubrication chamber therewithin.

In a hydraulic fishing jar adapted to be run into a well on a fishing string and connected to a fishing tool in the well bore;

• a. Inner and outer telescopically interengaged bodies;
• b. First diametrically defined pressure area having upper and lower sealed ends;
• c. First tandem piston means immediate one of said upper and lower sealed ends of said first pressure area;
• d. First seal means carried by one of said inner and outer interengagable bodies and engagable by the other of said inner and outer interengagable bodies and defining one of the upper and lower sealed ends of said first diametrically defined pressure area;
• e. Second seal means mounted on said first tandem piston means and defining the other of the upper and lower sealed ends of said first pressure area;
• f. Second diametrically defined pressure area having upper and lower sealed ends;
• g. Second tandem piston means immediate one of said upper and lower sealed ends of said second pressure area;
• h. Third seal means carried by one of said inner and outer interengagable bodies and engagable by the other of said inner and outer interengagable bodies and defining one of the upper and lower sealed ends of said second pressure area;
• i. Fourth seal means mounted on said second tandem piston means and defining the other of the upper and lower sealed ends of said second pressure area;
• j. Hammer means carried on one of said inner and outer telescopically interengaged bodies and anvil means carried on the other of said inner and outer interengagable bodies;
• and
• k. Means for preventing relative rotation between said inner and outer telescopically interengaged bodies;
• said first and second pressure areas being in fluid communication with one another, said first and second pressure areas defining a lubrication chamber therewithin, said inner and outer bodies being interengaged within at least one of the first and second diametrically defined pressure areas, said hammer means and said anvil means being within at least one of said first and second diametrically defined pressure areas, and said means for preventing relative rotation between said inner and outer telescopically interengaged bodies being within at least one of said first and second diametrically defined fluid pressure areas.