Casing Basics and Levels in Oil Drilling Rigs, Part 2

In part one of this two-part blog series, we went over some of the basics and levels involved with oil well casings. Oil well casing, or the structural foundation of a well that’s set inside the drilling area to protect and stabilize it, is a vital part of any new oil drilling process.

At Oilfield Equipment & Manufacturing, we provide a wide array of downhole oil and gas drilling products, including numerous casing areas for you to consider. In today’s part two, we’ll go into a few additional oil well casing types and formats to be aware of, plus the direct value they provide to these processes and why they’re necessary.

casing oil drilling rigs

Casing Liner

One of the most commonly used casing formats in the oil well drilling world is casing liner, which is often used throughout the industry. Casing liner is extremely cost-effective, allowing for the running of a casing string across the entire length of an open drilling hold without any need for running the string up to the surface.

For this reason, the casing liner can often be used as intermediate casing or production casing (more on this latter item in a moment). Casing liner runs into the shallower casing string, with an overlap of strings running between 300 and 500 feet in most cases.

Production Casing/Liner

The casing string or liner we mentioned above will be set at a depth above, midway in or below the pay zone. This choice will depend on the strategy you’re using to complete the well. When used in this manner, production casing allows for the following functions to take place:

  • Isolate production zones from other formations
  • Protect all completion equipment on-hand
  • Allow for annular passage for gas lift injection
  • Provide a conduit for various reservoir fluids
  • Contain formation pressure in case a tubing leak of some kind takes place during the process

Production Tubing

Finally, production tubing will be run into the well after the production casing is already fully in place. In addition, all the completion equipment will be run with this string downhole before the production tubing comes into place.

Production tubing has to be strong enough to support the required load, both now and in the future. Production tubing provides the primary conduit for oil, gas and water from formations, while also protecting the casing from any corrosion it might experience. The tubing also stops basic wear-and-tear and deposition from reservoir fluids from taking place, vital factors for allowing the completion of the process without any waste or accident risk.

For more on oil well casing types and formats used during downhole drilling, or to learn about any of our oil drilling products or solutions, speak to the staff at Oilfield Equipment & Manufacturing today.