Why Drill Oil Wells Directionally?

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Greetings friends and followers of my petroleum blog

On this occasion I would like to explain through this article the reasons why there may be a need to drill a well in a directional way when drilling an oil well.


Image Source. Licensing: Creative Commons Attribution 2.0 Generic. Author: Ditch Witch

What is directional drilling?

If we apply a little common sense we can then define directional drilling to all well drilling that is not executed vertically, however for my concept in particular all well drilling at the end is directional, since even to maintain control of the verticality of a well one must have clear and precise knowledge of directional drilling.

There are many types of directional drilling however the main objective of this article is to explain directional drilling under a focus on drilling wells in a directional manner with the intention of establishing a communication channel between the subsoil and the surface in order to extract oil from the reservoir that contains it.

what are the origins of directional drilling?

The first wells that were drilled were vertical, then it was that we evolved towards the directional technique. This move from vertical to directional drilling was quite slow, as initially the idea of being able to drill oil wells directionally did not look as attractive.

The real need that drives directional drilling is for locations that are difficult to access and under which oil fields could be reached horizontally or at an incline (directionally)

Study of reservoir simulation to justify directional drilling


Image Source. Author: Richard Banks

In the image above you can see a structural map generated from the study of the simulation of deposits. In this structural map you can see how it has the dimensions and characteristics of a large oil field.

The structural map if observed from left to right in the upper part shows a geological fault line.

The conclusion for this case of the structural map is that by means of the study of the simulation of deposits we can diagnose a geologic fault, in which to be able to make the perforation of a well to arrive at the producing deposit it has to be avoiding the geologic fault, and this only is obtained drilling of directional form.

In what ways is it beneficial to be able to drill using the directional technique?

The aspects that are beneficial to be able to drill directionally are diverse, however some benefits could be named according to some objectives to fulfill, and that can only be achieved if it is possible to drill directionally, among these benefits the following can be explained:

[1] With directional drilling it is possible to reach the producing field, mainly if it is difficult to reach the producing field by vertical drilling.

[2] With directional drilling, a set of wells can all produce from a single reservoir.

[3] In the event of a fluid burst such as gas and oil on the surface, an alternative may be to drill a deviated well to relieve the pressures of the producing reservoir.

Are there no complications with directional drilling?

Of course, like other techniques used in the oil industry, directional drilling cannot be the exception. Among the techniques that also present certain difficulties in their application is that of directional drilling.

Before the modern tools and equipment used in directional drilling could arrive, one of the main difficulties with directional drilling was the slowness with which an oil well was drilled and constructed if it was drilled horizontally or directionally.

Although these disadvantages have been considerably diminished with the use of modern equipment such as RSS, downhole motors, among others, there are still certain difficulties to overcome within directional drilling such as the excessive cost in the budget that has to be had to drill directionally, especially considering that the use of modern equipment that accelerated the drilling of directional wells, are the same ones that also increased their operating costs.



Image Source. Licensing: Public Domain. Author: U.S. Government Accountability Office

Conclusions and contributions

As an operations engineer of such an important oil field in Venezuela, as is the Tomoporo field, located in the south of the state of Trujillo. In this field I came to supervise operational activities in which type S directional drilling was contemplated, for this particular case I noticed the high operational costs in the use of directional tools that actually made directional drilling more expensive than conventional vertical drilling.


My general recommendation is that directional drilling should only be done if and when geological and petrophysical studies diagnose the use of the directional drilling technique as mandatory, not only for geological and petrophysical studies, there may be other compelling reasons to drill directionally, however if these compelling reasons do not exist, one should drill in the most conventional way possible, such is the case of vertical drilling, where one can reduce economic expenses considerably.

References consulted

[1] Mechanical. Drills through rock with acid

[2] Glossary of Geosteering terms

[3] DEVELOPMENT TENDENCY OF HORIZONTAL DIRECTIONAL DRILLING



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Thank you for your post. I have the same feeling with respect to directional drilling. This type of drilling aloear to be very common in the U.S. During teaching operation so the cost may be justified.

I never considered costs as a negative characteristic of this drilling.

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