Talk to any individual who works at management level in an oil company and they’ll all tell you the same thing; the biggest problems usually arrive from a loss of circulation. They may have found the perfect drilling location, got all of the parts delivered on time, but once the process has started there is nothing to determine whether or not problems will occur in relation to circulation.
Bearing the above in mind, it’s no surprise to see that umpteen companies are attempting to devise solutions that will ultimately prevent, or at least weaken, the effects of lost circulation. Some of these are proving to be very successful, while others are quite young and it remains to be seen just how the market reacts to them.
Nevertheless, whichever option an oil or gas company chooses, they are always going to go through the same process of determining this control method. Through the remainder of this article, we’re now going to take a look at some of the key control issues that have to be considered when a loss of circulation occurs.
What type of loss has been reported?
Before the process even begins, it’s up to the company to determine what type of loss has been reported.
- The general hope is that it will be of the minor variety, with this defining any loss that falls between the 6 and 470 barrels mark. Additionally, for the loss to be classified like this, it has to be ceased within 48 hours.
- The next type revolves around a severe loss and unsurprisingly, this can only be defined in instances where the losses are above the 470 barrel mark and when it takes more than forty eight hours to control.
- There is also a third type, although the instances of this happening are few and far between. This is called a total loss and as the name clearly indicates, this occurs when no fluids are returned to the service. Nevertheless, a total loss can still fall into the “minor” or “severe” category as well, depending on the amount of fluid and time that has been lost.
What control options are available?
Once the above has been determined, the control process begins. As strange as it may sound, some companies sometimes opt to not to take out any controlling measures as it’s sometimes deemed unnecessary. Naturally, this only usually occurs on the smaller leaks and once the loss of circulation reaches a certain point, it’s time to take things up a notch.
The conventional method is to take advantage of additives, which usually aim to increase the viscosity or even “block” the holes in which the liquid is escaping. In terms of the latter, it’s not been unheard for items such as golf balls or newspaper shreddings to be used, with the latter being particularly prevalent.
In the worst case scenarios, some companies will opt to pour cement down to the area where the losses have occurred. From this point on they can drill through the cement, and continue to extract the oil or gas as normal.