An In-depth Understanding of Liner Hanger

I. Structural composition of liner hanger

The liner hanger is mainly composed of liner hanger assembly, running tool assembly, sealing assembly, ball seat assembly, rubber plug, float collar, float shoe, central pipe coupling, etc.

II. Property of liner hanger

1. It is suitable for the casing opening side drilling, old well deepening and workover operations;

2. The unique hydraulic cylinder design ensures that the hanging is more reliable and can be used in different good conditions;

3. The rubber plug and ball seat are designed with a locking mechanism, which can prevent leakage and floating after bumping;

4. The sealing core can be lifted out of the wellhead with the tool.

III.  The operating principle of liner hanger

The liner hanger connects the liner string down to the hanging position and puts the pressure-hold ball from the wellhead. When the ball falls to the pressure-hold fulcrum bearing, build the pressure from the wellhead. The pressure difference between the inside and outside of the pipe pushes the piston downward to cut the hydraulic cylinder shear pin, which drives the slip to go up along the cone and close to the inner wall of the upper casing.

At this time, lower the tubular column makes the slip insert stuck on the casing wall to realize the liner suspension. After the hanging, pressurize the ball seat to open the circulation channel. The reverse connection between the inverted feed tool for forwarding turning drill string and the hanger is used to realize the liner loss after cementing.

IV. The purpose of liner hanger

The liner hanger qeuipment is mainly realized by hydraulic transmission, which is widely used in technical liner and production liner cementing of oil and gas wells, brine wells, and geothermal wells. Oil, gas and other wells liner hangers can be used for cementing in the following situations:

1. It is possible to save a lot of casing pipes and costs for exploratory wells and appraisal wells;

2. Well completion can be realized under the condition of reducing the load of casing head and surface casing;

3. Improve long-term cementing operation to prevent low-pressure leakage;

4. Simple and rapid sealing of the open hole section and the deepening as well as cementing of old wells;

5. Provide flexible good completion mode and relatively safe cementing operation;

6. The liner is connected back in the rock salt well section to enhance the sealing strength of the rock salt section;

7. Seal the damaged section of the upper casing (corrosion, fracture, etc.).