Drilling Jars
Mechanical and hydraulic jars that deliver impact to free stuck pipe.
- Hydraulic, mechanical and hydro-mechanical designs
- Up and down jarring capability
- Adjustable or preset firing loads
Downhole tools
Downhole Drilling Tools: Jars, Shock Subs and Reamers
Downhole tools protect the string, free it when it sticks and shape the hole to the size the well needs. They are often the difference between a minor event and a lost bottom-hole assembly.
Kronborr supplies drilling jars, shock subs, hole openers and reamers, with operating documentation your crew can follow on the rig.
The range
Downhole Tools: Product Families
Shock Subs
Absorb axial vibration from the bit before it travels up the string.
- Spring element to absorb axial loads
- Transmits full torque through the tool
- Designs for roller cone and PDC applications
Hole Openers and Reamers
Enlarge pilot holes and keep the wellbore in gauge.
- Roller cone and fixed-cutter options
- Replaceable cutters on many designs
- Pilot or bull nose configurations
Fishing Tools
Overshots, spears and junk retrieval tools for recovering lost equipment.
- Releasing overshots with basket or spiral grapples
- Releasing spears for internal catch
- Reverse circulation junk baskets
Freeing Stuck Pipe
A drilling jar stores energy as the string is pulled or slacked off, then releases it suddenly as an impact that can free stuck pipe. Placing the jar correctly in the bottom-hole assembly matters as much as the jar itself.
Controlling Vibration and Shaping the Hole
Shock subs absorb axial vibration from the bit before it travels up the string, protecting the bit, the string and surface equipment. Hole openers and reamers enlarge a pilot hole or keep it in gauge, ready for casing.
How to Choose Downhole Tools
Share your bottom-hole assembly design, hole size, expected loads and the problems seen in offset wells, such as stuck pipe, vibration or tight hole. We will recommend tools and their placement, and include operating limits in the data sheet.
FAQ
Downhole Tools: Common Questions
Where should a drilling jar be placed in the string?
Jar placement depends on the bottom-hole assembly, the expected sticking point and the weight available above and below the jar. Send your BHA design and we will advise on placement.
What does a shock sub do?
A shock sub absorbs axial shock and vibration from the bit, protecting the bit, string components and surface equipment, and often improving bit life.
What is the difference between a hole opener and a reamer?
A hole opener enlarges an existing pilot hole to a larger diameter. A reamer is usually used to keep the hole in gauge and smooth its wall, though the terms are often used loosely.
Tell Us What You Are Drilling
Send your well program, sizes or part numbers. We reply with a quote and a reference number.