Directional Drilling for Dummies

Mud motor basics

The staff petroleum geologist doesn't stick his head up all that often these days, but we though we'd prevail upon him to share a little of his knowledge about the oil business (aka the "awl bidness"). After all, we see a massive amount of misinformation here from freelancers whose only exposure to the industry is the local BP station. Heck, our guy consulted to BP several times. Whatever the case, we're knocking out two birds with one stone here, not only putting rock guy back in harness, but checking up on Infobarrel.com¹ as well. That's where we found John Crew attempting to explain "Oil Field Jobs: The Directional Driller."

Crew may have thought that his brief career in the oil patch made him an expert, but it takes more than a few months as a roughneck to get a handle on a business most don't realize is highly technical. Just for starters, Crew's already proven that he doesn't understand oil reservoirs, but the sad fact is that he shares that ignorance with a lot of people (see the list here under "oil"). He picks up right where he left off this time, by telling his readers that,

"Oil forms in the earth as a layer. This layer can be a shallow as 1000 feet or as deep as 7000 feet. Within this layer lie larger pockets of oil that were drilled for using straight down drilling methods. This is because the old techniques involved drilling straight down and coming back out. Therefore, finding the largest pocket of oil was the goal."

Of course, those who actually know something about the business know that there is no "layer" of oil down in the ground and no "pockets" of the stuff, either. Instead, there are reservoirs, layers of porous rock that hold fluids including oil and sometimes gas in the spaces between grains. As for Crew's "drilling straight down and coming back out" stuff, we're at a loss. Whatever the case, that's John's ham-fisted way of introducing the reason for horizontal drilling. That, he describes as,

"Industry scientists knew that the larger share of the oil was trapped in a thin layer, about 100 feet thick, and was difficult to get to. 99% of the time the layer was too thin to justify drilling straight down to it and sucking out what little you could get."

Well, no, John, that's not why they go horizontal: they go horizontal because the oil-rich layers have very low permeability or are impermeable, so they want to expose  as much of the rock to the wellbore as possible (that's according to one of those "industry scientists," BTW). Crew then prattles on about the process of operating what's known as a mud motor – but he gets stuff wrong, stuff like,

• "The first tool is that the motor, which sits on top of the drill bit. The motor is bent at an angle... This allows the driller to literally ‘drill into a curve’. Back in the old days the motor was a straight pipe, but someone realized that if you put a slight bend into it, you can control the way the drill bit goes." – No, John, there were no mud motors in the old days: the entire string of pipe was turned by a big-ass diesel engine at the surface.
• "The motor is used in two different ways to direct the bit. The first drilling method is called sliding, the second is called rotating." – Nope, the downhole motor isn't used when the pipe is rotating...

Crew's ignorance of the operation extends to his understanding of the pay. According to John, the driller on his crew makes, "$4,000 monthly salary, $800 day rate, $45 per diem..."; telling his readers that a driller's monthly pay works out to "$31,450 gross for 30 days worth of work [bolding and underlining John's]." Clearly, he does not understand day rate and per diem: it's a lot more likely that his engineer pulls down $4,000 a week, and his company charges him out at $800 per day (our staff guy was charged out at $120/hour in the old days), which actually seems low. Those who've been paid a per diem know it is intended to cover your expenses, not go into your pocket...

On top of all that, Crew seems to think that directional drilling occurs only in horizontal wells, and is a relatively new technique. Nothing could be further from the truth: directional drilling has been going on for since before World War II, and is routinely used in all sorts of settings where a company can't place a well directly on top of a target (a target is one of John's "pockets"), especially from offshore platforms. Duh. Once again, Crew misstates the science behind behind the oil business and also makes a hash of the processes he describes. We're pretty sure that doesn't qualify him to be a drilling engineer, but he sure makes a fine Dumbass of the Day.

¹ InfoBarrel has deleted all user-generated content and become a "green" website, but this post can still be reead by using the Wayback machine at archive.org. Its URL was   infobarrel.com/Oil_Field_Jobs_The_Directional_Driller_

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