Oil Well Drilling Primer

[Minuteman]

Reading Monkeymans butchering tutorial got me to thinking about doing this. So here goes.

Over the years I have had several people ask me questions related to drilling an oil well. I began writing this "Primer" but have found that it is quite exstensive and to long for a single post. Plus it is not as informative without pictures. We are just starting a new well and I thought that I would create a thread of the process.Take you through the entire process, with pictures. So I hope you all enjoy it. BTW due to my schedule it will take a few weeks to get the entire well documented.

For those who don’t know, I work in the oil business. Specifically in the drilling and workover phase. I have been in the "Patch" 30 years this April. I call it the unknown proffesion. Most people don’t have a clue how it works. We all know what a plumber does, a carpenter, lawyer, cop, doctor, surgeon. But unless you have been in the industry you really have no idea how the oil business works.

I thought that I would give a basic "Primer" here for those interested.
Television has done more harm to the oil business than any other thing in history. The wild "gushers" of oil spraying in the air. Jed Clampett shooting at a rabbit and "up from the ground comes a bubbling crude". And of course the archtypical big oil villain "J.R. Ewing.

First of all lets deal with gushers. The sight of oil spraying into the air is very dramatic and makes good television. But it is mostly Hollywood. The reason oil sprays into the air is that it is being pushed out of the ground by the pressure of natural gas. While this occurred in Texas in the early days of the oil business it is not something that you want to see. We, as an industry, soon learned how to control these abnormal pressures and keep them in the well bore. Gas escaping into the air is, of course, highly flammable. One spark and all the oil that has sprayed out, not to mention the rig and all the people, would be incinerated.
I attend school every other year to maintain my "Well Control Certificate". We constantly train to control these "Blowouts". To recognize the indicators and to prevent it from happening. If oil comes shooting over the top of the rig I am on, then I haven’t done my job, and will be looking for another.

Many people think of drilling an oil well like sticking a straw into the ground and sucking out the oil. Most people think of oil as an underground lake. It is actually more akin to a vein of gold imbedded in a rock formation. Most oil producing formations are either a highly compacted sand or a dense shale. Core samples taken from these zones are a round (6 - 8 inch usually), long (anywhere from 30 to 90 feet), sample of rock. The oil can be seen in small finger sized "veins" running through it.

When produced, the oil seeps into the well bore and then is pumped to the surface. It is much more like getting fluid from a wet sponge than sucking it through a straw.

The process begins by staking a location. After examining all of the available data a drill site is determined and after all the paper work, lease agreements etc. are in order, a stake is set in the ground marking the spot to drill.

The geology of an area consists of layers of rock, sand, shale. Only certain formations contain oil. These differ in different areas. For example the "Barnett Shale" formation is a layer of oil saturated rock that starts in West Texas and runs across the northern part of the state all he way into Louisiana. Some formations are only a few miles long.
The exact spot to drill is determined by researching wells drilled in the area and by siesmic recordings taken in the area. Once the spot is determined a well plan is drawn up. It is basically a step by step program or guideline for drilling the well. We will drill this size hole to this depth and set this size casing etc.

The next step is to build the location. Dozers level the area and usualy haul in rock to build a "pad" around the proposed well. The size of this location depends on the rig used to drill the well and how much area is needed to place the rig and all its components.

This is the site of the new well that we will drill. A small truck mounted unit comes in and drills a "Conductor hole" and installs a "Cellar" to contain the drilling mud and keep the location cleaner.. The "Conductor Pipe" is the pipe in the middle of the "Cellar". This one is 60' deep. You can start drilling from the ground without a conductor, but this just makes it easier and not so messy.

[Minuteman]

The next step is to move in living quarters for the people who will be drilling the well. These are Trailer houses with self contained sewage and potable water systems.
Once drilling starts it will continue 24 hours a day 7 days a week. So the people working on the well have to be on location 24/7 also.
The oil company representative "Company Man" who oversees the entire operation, the "Mud Engineer" who supervises the mixing of the drilling fluids, and other service contractors, live on site.
The oil company is responsible for providing housing for them. The drilling contractor who supplies the drilling rig provides living arrangements for their personell.

The trailers and their systems;

[ghrit]

I'm gonna learn something here, all good. I've driven piles, bored piles, and made a bunch of holes in the ground with all sorts of machinery and bang bang materials. Even raise bored. But never so deep or technically challenging (excepting tunnels.) Always wondered how it was done, especially directional drilling. (Had one old timer, when asked how directional drilling was done, told me, "I stand at the well head and hollar
GEE or HAW depending on which way I want it to go." I stopped asking --)

[Minuteman]

We have on site communications, including satellite internet and phone service and sattelite TV.
I am the oil company representitive or the "Company man". Some Company Men work directly for the company, others like me are independent consultants who are contracted to the oil company. Our job is to supervise every aspect of the drilling process.
We hire a lot of the services needed during the drilling process and we make sure that the well is drilled efficiently and cost effectively.

[Minuteman]

Then the Drilling Rig is moved in on trucks. Winch trucks and cranes spot the rig components and assemble it.

[Minuteman]

That's as far as we are so far. We will start assembling the rig tomorrow. I'll get some good pics of that.

[Quigley_Sharps]

Very Cool MM Im really going to enjoy this thread.

[Minuteman]

Originally Posted by Quigley_Sharps

Very Cool MM Im really going to enjoy this thread.

Your new job was one of the inspirations to share this. Hope you enjoy it.

[Tango3]

Love this kinda stuff, ( how its made kinda shows are fascinating)Thankyou verymuch, most of us have neverseemn this side ofit...The sheer fact each tube is threaded to the next all the way in and back out is amazing.. my dad was an independant trucker who hauled drill pipefrom the mill out to the rigs in no texas and the ok panhandle for alot of years..I made 1 trip with him,never saw this end...

[Minuteman]

This is the "mud" tanks that hold the drilling fluid. And the 2 mud pumps that pump the "mud" up to the rig floor and through the drill string and out the bit. These pumps are "tri-plex" with 3 pumping rams that put out a maximum of 300 gallons per minute for each pump. Their powered by Caterpillar D-398 diesel engines.

[ghrit]

WHOA!! Those are serious pulsation dampers!! What pressure do they put out? What's the viscosity of the mud?Polymeric, I assume --.

[Minuteman]

The back side of the mud tanks. The mud is pumped down the drill string and out the bit. It serves several purposes. It cools and lubricates the drill bit. much like squirting some oil on a hand held drill bit while drilling a hole through metal. But unlike a hand held drill bit, these don't have a spiral channel to bring the cuttings out of the hole. They grind up the formation into small pieces or cuttings. The viscosity of the drilling fluid is increased to carry these cuttings with it as it returns up the hole. We use "Bentonite" to vis the mud. This is basically a rock,common in Wyoming that is ground up to a powder. When mixed with water it becomes very thick. To add wieght to the mud, used for well control, we add "Barite". Another crushed rock, but very dense and heavy. A 100 pound sack of barite is half the size of a 100 pound sack of bentonite.

The fluid being pumped through the pipe and out the bit, keeps the bit cool and lubricated, and brings the cuttings out of the hole and to the surface. A longer conductor pipe is welded on to the one in the cellar and it has a "tee" section. A pipe called a "Flow line" channels the mud back to the mud tanks where it flows over a "shaker", like the screened shaker boxes used to sift ore, the fluid passes through the screens and returns to the "mud tanks" while the ground up materials from the hole are sifted out and slide down a ramp to a catch pit.
Most wells are "spudded in" with water, but sometimes a spud "mud" is needed to bring the cuttings out of the bore hole. When drilling for oil first began in Pennsylvania in the mid 1800's, water was all that was needed to clean the hole. When drilling began in Texas the formations being drilled were much more dense and heavier and the cuttings would not come up with water. A "Roughneck" suggested using thicker muddy water. They had an earthen pit with a couple of feet of water in it. They herded some cattle into the pit and drove them back and forth to churn up and muddy the water. The idea worked and today the Drilling Fluid industry is a multi-billion dollar business.

[Minuteman]

Originally Posted by ghrit

WHOA!! Those are serious pulsation dampers!! What pressure do they put out? What's the viscosity of the mud?Polymeric, I assume --.

These are Gardner Denver PZ 9 mud pumps, a medium sized pump. They put out max of 3500 psi. The "mud" usually runs around 40 to a 80 viscosity. For reference the vis of water is 26. I guess I should explain. The vis is checked by running the mud through a hand held funnel and timing how many seconds it takes to fill a quart. So water is 26 seconds a quart.
The pulsation dampeners on the mud pumps (the round red thing that says "Hydril") contains a bladder that is filled with nitrogen. The mud being pumped, pulses against the bladder and that takes out the surging of the pressure. Makes the pressure constant and even.

[Minuteman]

The sub structure is what the derrick sets on. It is the work floor and also where the drill pipe is set when pulled out of the hole. It is brought in and centered over the conductor pipe. Then it is leveled. And this particular rig has a hydraulically scoping sub base. After it is set a hydraulic pump is hooked up and it is raised to twice it's hieght.

[ghrit]

Side light: Pulsation dampeners serve a purpose very much like the shock arrestors that most (if not all) houses have in the water lines. Anyone having pipe noises when shutting off the water in a sink or flushing a toilet knows the noise well if there is no shock arrestor installed. Usually, if one is there, you'll find it on a cold water pipe. In essence, there is a gas pocket (air in the homes) that compresses and expands as needed to take water hammer (surge pressure peaks) out. Water hammer results from starting a flow, then stopping it abruptly; the inertia of the fluid slams things, thus the noise. In extreme cases, damage to parts results, sometimes causing leaks. This isn't too common in housing, because the pressure in the mains is usually controlled. I've seen some BIG pipe move dramatically in water and waste water service when the pressure is not properly controlled.