How To Install Casing Pipe in Deepwater Wells?

In the field of drilling, casing pipe, as a common OCTG pipe, is an indispensable tool. So what are the methods for installing it in deepwater wells?

Riser method for casing pipe installation

Riser method is a common method for deepwater well casing pipe installation, mainly installing casing pipe on the sea surface. This method can ensure the positioning accuracy of the casing pipe and can be adjusted during the installation process. Its advantage is that it can ensure the positioning accuracy of the casing pipe and facilitate adjustment, but it requires piling construction, which increases the difficulty and cost of the work.

Riser method installation steps

1. First, piling construction should be carried out after underwater survey. This ensures that the casing pipe can be stably placed on the seabed.

2. Then, use a crane or a lifting boat to place the casing pipe within the steel pipe length and accuracy control range of the pile driver. The vertical positioning of the casing pipe can be completed by controlling the length of the steel pipe.

3. When the casing pipe is completely placed on the seabed, connect the pipe fittings and handle the seals between the casing pipe and the wellbore.

4. Finally, fill the well to minimize the buoyancy difference inside and outside the well.

Floating method to install casing pipe

The floating method is a relatively new method of casing pipe installation, which is suitable for shallow waters. This method places the casing pipe on a buoy and then transports and installs it by ship. Its advantage is that it omits the piling construction step compared to the riser method, reducing the difficulty and cost of the work, but it is not accurate enough and the position of the casing pipe cannot be adjusted.

Floating method installation steps

1. First place the buoy where the casing pipe needs to be installed.

2. Then place the casing pipe on the buoy through the lifting device and ensure that there is no collision between them.

3. When the casing pipe and the buoy are firmly connected, the ship can be used for backlog connection and the seal between the casing pipe and the wellbore is handled.

4. Finally, fill the well to reduce the buoyancy difference inside and outside the well.

Summary

There are two ways to install deepwater well casing pipe: the riser method and the floating method. Choosing the appropriate method requires considering the specific situation and needs. At the same time, during the installation of the casing pipe, some issues need to be paid attention to, such as the diameter of the wellbore, the length of the casing pipe, etc. Only by fully mastering the relevant knowledge and strictly following the operating specifications can the quality and safety of the casing pipe be guaranteed.