Don't Assume All Skin Is Due To Damage

I'm sure you've heard the mantra before, "What happens when you assume? You make and @$$ out of U and ME." That has stuck with me, partially because I've been burned more than once for making silly assumptions, and I'm sure I'm not the only one. We could probably have an entire Engineering Tip just on the topic of assuming, but today I want to get a little more specific.

For those who are not aware, when a petroleum engineer talks about skin, they don't mean the stuff that covers your body. They are talking about "skin on a well", which is a measurement of how good or bad a well is performing relative to it's maximum potential. Simply put, more skin is bad, less skin is good. And we calculate skin through well testing.

With that in mind, here is where I'm going with all of this. When we test a well and get a skin factor, it's easy to assume that the skin is due to damage and that the skin can be removed with a simple workover treatment. While that may be true, there are other forms of skin that can occur on a well, and a simple acid treatment might not due the trick. Other factors of skin include partial penetration, spherical flow, turbulence, inclination and perforations. When you see skin on a well, it's important to take a deeper look and try to understand what might be causing that skin. If you have a well with partial penetration, an acid treatment is not going to solve the problem. The only thing that will remove that skin is deepening the well, which may or may not be practical.

My point here is this, damage is a major factor that contributes to skin on a well, but it's not a guaranteed that all skin is caused by damage. Take a deep look at things and see if there is a bigger issue going on. If not, then by all means go forth and remove the damage. Just don't assume, or you may find yourself haunted by the voice in your head asking, "you know what happens when you assume, don't you?"

If you are interested in learning more about skin on a well, check this out.

Take Care of Your Master Valves

Master valves are your last line of defense on a well. Without a reliable master valve, your well control is compromised, and that is never a good place to be. I have had the opportunity to work on a lot of old, mature wells, some which still have a lot of pressure, and it amazes me how many of them have master valves that are either leaky or extremely difficult to turn. If you were in trouble and had to close that valve quickly, you'd be out of luck.

Why does this happen? The answer is pretty straight-forward. Valves need regular maintenance just like any other mechanical device. It costs money to change the oil in your car, but you do it anyway because your car valuable and the cost of failure is large. Master valves are also extremely valuable. Take care of them. Keep your valves greased up and when they need repaired or replaced, spend the time and money to do it the right way. In the grand scheme of things, this is a small expense to keep your wells safely under control.