What is stove pipe in oil drilling?

In oil and gas drilling, a stovepipe refers to a section of large-diameter casing used to temporarily isolate and protect a wellbore while deeper sections are being drilled. It serves several important purposes:

Well Control: The primary function of a stovepipe is to provide well control during drilling operations. It acts as a strong and secure casing that can withstand high pressures and prevent fluids from flowing uncontrollably from the wellbore.

Casing Protection: The stovepipe protects the production casing or liner that will eventually be installed in the well. By isolating the upper, weaker formations from the drilling process, the stovepipe helps prevent damage or collapse of the production casing.

Drilling Fluid Return: The stovepipe allows drilling fluids to be circulated and returned to the surface during drilling operations. This enables the removal of cuttings and helps maintain wellbore stability.

Blowout Prevention: The stovepipe provides an additional barrier to prevent blowouts, which occur when well fluids escape uncontrollably from the wellbore. It enhances safety and allows drilling operations to be conducted in a controlled manner.

Casing Cementing: After the stovepipe is set in place, cement is pumped into the annulus between the stovepipe and the formation to create a strong seal. This process, known as casing cementing, helps isolate different zones, prevent fluid migration, and ensure well integrity.

The stovepipe is typically installed prior to drilling deeper sections of the well. It is usually removed once the production casing is set and cemented in place, allowing for the continuation of drilling operations.

The use of stovepipes is crucial in ensuring wellbore stability, preventing uncontrolled fluid flow, and maintaining overall safety during drilling operations.