What are the basic principles for dealing with an oil well blowout? | Petroleum Engineering

in hive-196387 •  12 days ago 


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We could associate the term emergence as something that emerges or enters.
That said, we can conceptualize an upwelling as the phenomenon that describes the unwanted entry of fluids such as oil and/or natural gas from the formation (reservoir) into the well.

What consequences can arise if an upsurge occurs while drilling an oil well?

The immediate results after an occurrence during the attempts that can be made during the drilling of a well are the lost operating time, since the programming for the construction of a well has a time contemplated (programmed time) and that in the attempts to control the well the real construction time will exceed the programmed time. Also as a serious consequence must be included all the high risk operations that are performed having the oil and natural gas on the surface, taking into account these high risk operations can lose control of the well obtaining the possible loss of equipment and human beings.

However, the fact that a surge occurs within the well does not mean that there is nothing left to do and that we only have to wait for the tragic consequences. If the surge is recognized in time, it may be controlled in time, since a surge detected in time can easily be worked on so that those fluids such as oil and natural gas that have been invaded within the well can be expelled from the well in a safe manner.

When we drill a well, and even more if it is exploratory, many of the formation pressures are unknown, which is why an upsurge of undesirable fluids into the well can occur at any time during the drilling process. For this and many other reasons, engineers and supervisors at the drill rig must be able to recognize this upsurge, and not only recognize it, but be able to identify it and react to all the indicators.

The indicators or elements that can give us an indication that fluids such as oil and/or natural gas have already entered the well are very important objectives that I will explain in this article, with the intention that if some of these indicators occur we can be aware that we are under the presence of an upsurge.

The reason why I will explain the basic principles of upwelling in an oil well is because understanding the pressure indicators, warning signals, and why upwells occur can decrease the chances of a fluid surge such as oil and natural gas and cause a blowout where large material and even human losses occur.


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Causes of oil well blowouts

There is only one condition for the emergence phenomenon to occur in the drilling of an oil well, this condition is that when the formation pressure (also known as reservoir pressure) is greater than the pressure exerted by the column of drilling fluid, fluids such as oil, gas and water invade the well and can migrate to the surface causing an onslaught of unwanted flows and subsequently cause a blowout.


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Indicators of a kicks

Variations in drilling speed: if the speed at which we are drilling the well changes, and starts to increase suddenly, it is because we may be in the presence of an increase in formation pressure.

These sudden changes of increased penetration rate should not occur, because as we go deeper into the borehole the drilling speed tends to decrease, since as we go deeper into the borehole we get strata that are increasingly hard and difficult to cut with the drill bit.

What happens to the drilling speed when formation fluids invade the well?

As there is more fluid at the bottom of the well, since we would have the drilling fluid plus the formation fluids, the wick cuts the formation faster because this excess fluid softens the formation, and a soft formation may be easier to cut through.

The perforator in his cabin has a parameter reader panel where he can observe if the penetration rate increases suddenly, if this occurs the perforator must immediately report it to the drill supervisor.

[1] Increase in torque and/or drag: this is an indicator that is very much linked to the increase in the penetration rate, if the speed with which the wick is cutting the formation increases, there will be a lot of clippings that will accumulate around the drill string, preventing it from turning so the torque will increase. We can then say that the increase in torque is a good indication of the increase in formation pressure and the invasion of undesirable fluids into the well.

[2] Increased gas content - increased gas content in the drilling fluid is a strong indicator of abnormal pressure zones. However, gas cuts are not always the result of an unbalanced condition, so a proper understanding of gas trends is important.

[3] Increased Chloride Content - One of the elements that quickly enters the drilling fluid is the chloride ion when formation fluids invade the well, so chlorine or salt in the mud is another indicator of increased formation pressure.


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Conclusion of the points explained in this article and contributions within petroleum engineering

This article presents all the technical characteristics of engineering with an educational approach that will allow the reader and anyone interested in knowing a little more about oil material to distinguish the causes and indications of a possible emergence in the drilling of an oil well.

However, if we find ourselves in an adverse situation where we have already exhausted all resources to control a well where it has been quite some time since fluids such as oil and natural gas have invaded the well, and we do not know for sure what to do, it is advisable that due to indecision it is better to close the well.

It is not such an easy decision to close a well, since all the human effort and investment made in the construction of the well will be lost, but it is better to lose a well and keep human lives and equipment, than to lose the well, human lives and all the drilling equipment.

When the time comes to close a well, the right decision must be made quickly and firmly, there may not be time for a second opinion. The well is gaining momentum while one is trying to decide what action to take, when in doubt it is better to close the well. The cost of closing a well compared to the potential loss of resources, equipment and human lives is negligible. The procedures for closing the well must be established, known and executed.

All personnel present at the camp for the construction of an oil well, especially inexperienced personnel, should be trained in well closing procedures. Once trained, they should practice to the best of their ability.

From experience I can tell you that I have never had an event of this nature, and when I say an event of this nature, I mean an unwanted influx of fluids into the well. However, PDVSA offered me during the three years of experience the three levels of the well control course, through these courses I was able to learn and come to the conclusion that the most expert in well control, is not the one who controls them, but the work team that knows how to interpret the readings of the emergence indicators and at the same time acts in the most appropriate corrections so that the emergence inside the well does not take shape, and in this way we do not go through the imperious and undesired event of a blowout in an oil well.

References consulted and recommended

A short description of how to close an oil well by Schlumberger

Basic oil well control manual by issuu

Slideshare well control

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