The structure and usage of lead molds

1. Purpose

Used to detect the top status of fish falling underground and the condition of the casing. By analyzing the marks and depths left by the contact between the lead mold and the fish top, the position, shape, state, and casing of the fish top can be reflected

Preliminary information such as deformation is used as a qualitative basis to provide reference for construction operations.

2. Structure

The lead mold is composed of coupling 1, short section 2, tie bar 3, and lead body 4, with a water eye in the center for flushing the fish top. As shown in Figure 1-1.

3. Technical parameters

4. Usage

(1) Check that there are no scars around or at the bottom of the lead mold column that may affect the judgment of imprints. If there are minor scars, they should be repaired and leveled in a timely manner with a file.

(2) Measure the external dimensions of the lead mold. If the lead mold is formed in one go and the lead body is conical, the bottom diameter of the lead mold should be taken as the diameter of the well, and a sketch should be left.

(3) Apply oil to the threads, connect the drilling tools, and run them into the well.

(4) The drilling speed should not be too fast to avoid bumping and deforming the lead mold midway, which may affect the analysis results.

(5) When reaching the top of the fish, turn on the pump for flushing. After the fish is completely flushed, pressurize and print.

(6) The drilling pressure for printing is generally increased by 30kN. In special circumstances, it can be increased or decreased appropriately, but the increase in drilling pressure cannot exceed 50 kN.

(7) Press and print once to start drilling.