Well drilling problems: Loss of circulation

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Hello friends and lovers of STEM content, especially related to engineering in all its aspects.

This time I want to explain a very delicate problem that can occur when we are drilling an oil well and, as a petroleum engineer and supervisor of operational drilling activities we must be very vigilant to detect and correct and thus avoid problems when the problem of lost circulation occurs in the drilling of an oil well.

There are multiple problems encountered in drilling that have a strong degree of importance at the time of detection and control, however the lost circulation is one of the most delicate problems to deal with in the drilling of an oil well, when I refer to the term lost circulation I mean the drilling fluid that is lost to the formation while the fluid is being circulated in the well through the existing pumping by the mud pumps from the suction tanks to the bottom of the well and throughout the circulation of terno to reach back to the active tanks.

It is said that this problem is critical to occur because if all the drilling mud is lost, backpressure may be lost in the well and thus may migrate fluids such as gas and oil from the bottom of the well to the surface, thus achieving the most critical situation of all, i.e. there is a probability that if all the fluid is lost to the formation may occur a blowout and a possible fire on the surface, causing considerable human and economic losses.

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What are the consequences of a loss of drilling mud circulation to the well formation?

We must keep in mind that if the loss of drilling fluid to the formation occurs partially, the consequences are not devastating, however if the loss of drilling fluid is total, i.e. if all the drilling fluid is lost to the formation, unfavorable consequences may occur. It would be important to list some analysis in case this occurs:

[1] Si todo el fluido se pierde hacia la formación la presión hidrostática disminuye, por lo tanto los fluidos que se encuentran contenidos en la formación como gas y/o petróleo no podrán ser aguantados y migran hacia la superficie pudiendo así ocasionar un reventón.

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[2] If all the fluid is lost to the formation, it is very likely that there is damage to the formation, and when I say that damage to the formation can occur, it is because the pores of the rock are plugged and fluids such as oil cannot get out, therefore future oil production is highly affected due to the damage to the formation caused by the loss of circulation.

[3] The first thing we are taught as well drilling engineers is that we must be optimal in our actions, which brings as a consequence that our actions must generate little investment costs in the wells that are being drilled, as drilling engineers if we let a lost circulation occur logically we will have to prepare more drilling fluid to replace the lost drilling mud, this new preparation of drilling mud will bring new operating costs that were not in the initial planning.

We must avoid above all the occurrence of a loss of circulation because this would result in new economic costs.

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Conclusion

Drilling problems trigger a series of problems associated with problems that occur initially, for example one of the problems explained in the previous post explain the formation fracture as one of the problems that occur in drilling wells, however there is a problem that arises due to the fracture of the formation and this is the loss of circulation.

That is why it is most likely that if we want to solve a problem in the drilling of wells the most convenient would be to solve the problem that causes the problem we are trying to solve immediately.

Bibliography consulted

Downhole procedures and operations. DATALOG Drilling Manual. Version 3.0. March 2001. See page to download book in PDF format