In order to make oil and gas well wellbore unblocked, it is necessary to clean up and salvage the falling objects or their deposits caused by various reasons in the production process.

 

The methods and steps for salvage should follow the following principles:

 

1. Make clear the basic situation, including the well body structure, the cause of falling objects, the depth position of falling objects in the well, whether there is deformation, sand burial, etc., and if necessary, lead mold or logging test can be made to comprehensively analyze the position and form of falling objects in the well;

2. Choose suitable fishing tools or design and make tools according to the situation of falling objects. The problem of falling objects getting stuck should be considered.

3, rod and tube falling objects to consider the use of hook, shoes and other tools, so that the fish fall into the tool.

4, rope fall not bottom hole like rod tube falling objects falling, but in the middle, scattered pattern is not fixed, depth and fish pattern is not easy to master, the surface is easy to cause sticking over the tool, so select tool, consideration should be given with a big head pressure plate (also known as the limit board), the diameter of the pressure plate should be greater than the difference between the diameter of casing diameter and falling objects.

5. It is possible to judge whether the object is caught according to the change of suspended weight. For light objects, it is necessary to judge whether the object is caught according to the characteristics of the tool or the change of fishing depth.

6. If necessary, the milling method can be considered for auxiliary salvage treatment.