Oil well casing helps support the sides of a well after it's been drilled. The casing acts as a barrier that keeps soil, rocks, water, and other materials in the ground from entering the well and contaminating the material you're trying to extract. A leak in the casing is a serious issue, but because the casing is in the ground, running hundreds of feet down, you can't really peer down into the well and look for a leak. Sometimes you'll find the product you're drilling for has been contaminated with something, and that's a good indication that there is a leak in the casing, but other times you won't notice anything because the leak is new and not yet affecting things on a visible level. So, how do you find out if your well casing is now cracked and leaking?
Casing Is Literally Cemented In
Well casing in oilfields is cemented in. When the wellbore is drilled, the casing is slipped in right afterward, and cement is poured in between the casing and the dirt sides of the bore. That cement holds the casing firmly in place. When there is a leak, both the casing and the cement have cracked all the way through. Of course, cement isn't that flexible, and if there is seismic activity, too much pressure against the casing, or something hits the casing, the cement can crack easily.
You Have to Do Periodic Temperature Surveys
Oil drilling companies have to do something called a temperature survey of wellbores to detect casing leaks. When the survey shows anomalies in the temperature readings, that can indicate if there is a leak. Pressure testing is also a way to detect leaks. When a leak has been detected, repair has to occur immediately to prevent contamination and loss of gas or oil. Well casings can be patched in a couple of ways, so fixing a simple leak isn't that hard, relatively speaking.
Patching Options Include More Cement
Patching the leak with cement is straightforward and very common. However, if the cause of the original leak hasn't been fixed, that cement could crack, too. For example, if the cause of the first leak was too much pressure, then the same pressure could affect the new cement. Still, it's a fast patch that can stop the leak quickly while you work out other remedies and repairs.
If cement isn't an option, you still have a number of tools and repair choices that you can use. Yours is not the first company to have an oilfield well casing leak, and with the right tools, you'll make that leaking casing sturdy and whole again.
For more information, contact a local company that has downhole oilfield casing tools.