The Detail Introduction of Drilling Jar

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  • The Detail Introduction of Drilling Jar


In drilling operation, there often happen drill blocked due to complex geological structure (such as borehole collapse, bare eyes formation and extrusion plastic flow), improper technical measures (such as the pump stops for too long, bit balling, etc.). Drilling jar is an effective tool to solve drill blocked. 

The main using type of jar concludes drilling jar, fishing jars and ground jars. The drilling jar should be set in drill string combination. If encounter sticking in the process of drilling or tripping, drilling jar can solve the problem at any time. Just when you need it stuck well, can the fishing jar work. And it can’t work for a long time. Ground jar only use at the wellhead. Its shock effect of the card points is downward shock. It is more convenient to use in the field.

The structure of drilling jar can be divided into mechanical, hydraulic, mechanical-hydraulic three kinds.

Drilling Jar

Mechanical drilling jars. It use the theory of mechanical friction.The locking mechanism used kava. Mechanical jars can be designed into adjustable and non-adjustable shock force two kinds. Adjustable jar adjust its shock force at the wellhead. The shock force of non-adjustable jar is set in the product assembly and can’t be adjusted in the process. But it is short and safe, reliable. Mechanical drilling jars set high standard to metal material and heat treatment, precision machining.

Hydraulic drilling jar. It regards damping effect produced in hydraulic oil flow in the flow path as the locking mechanism. Hydraulic drilling jar can only generate shock in a single direction (usually upwards shock) due to its locking mechanism limitations. Due to long delay function which superior to mechanical jar, its size can be jarring force by operation of any regulation driller. The Hydraulic drilling jar is strict with seal design and selection of materials and the machining accuracy.

Combined mechanical-hydraulic drilling jars. It concentrates the advantages of these two jar principle. Even if the hydraulic delay shock function failure, mechanical drilling jars can work. Its technical performance get a high improvement and it is closed to the direction of drilling jar development.

Drilling jar plays an important role in drilling. Correctly choosing and using jar products can play its proper performance. For the drilling industry, it bring greater economic benefits.


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