Oil Well Drilling Primer

Discussion in 'General Discussion' started by Minuteman, Jan 27, 2007.


  1. Minuteman

    Minuteman Chaplain Moderator Founding Member

    Tripping

    Now that the hole is clean we need to remove the drill string so that we can run the casing. It would not be practical to lay down each joint, like we picked it up. We will remove all the pipe from the well several times during the course of the well. So we pull out 3 joints at a time. Some rigs are doubles and can only pull 2, but ours is the more common triple derrick.

    The Kelly is set back into the rat hole and the hook opened and removed. A tool called the "Elevators" is picked up and put on a set of links that hang from the traveling blocks.

    The drill pipe has a tapered shoulder at the tool joint. The elevators are tapered and can be opened and closed. They are closed around the drill pipe and when the blocks are hoisted the drill pipe tool joint shoulder seats into the taper of the elevators and the string is hoisted.

    We pull three joints out and set the slips. The tongs break the connection and it is unscrewed. The driller picks up the "Stand" and the roughnecks push it over to the side of the floor to the racking boards. The driller sets it down. The derrickman works on the derrick board, 90 feet above the rig floor. He throws a rope around the top of the stand and when it is set down he opens the elevators. He pulls the stand back into the board and puts it into a finger and ties it in. The driller lowers the blocks and a floor hand closes the elevators on the pipe in the rotary table and the next stand is pulled. This is called "Tripping Pipe". A round trip is the bit to surface and then back in the hole to bottom.
    set kelly back.JPG PIC_0135.JPG PIC_0141.JPG PIC_0147.JPG PIC_0149.JPG
     
  2. Minuteman

    Minuteman Chaplain Moderator Founding Member

    tripping

    More Tripping;
    PIC_0154.JPG PIC_0155.JPG PIC_0156.JPG PIC_0159.JPG PIC_0295.JPG PIC_0294.JPG PIC_0289.JPG
     
  3. Minuteman

    Minuteman Chaplain Moderator Founding Member

    Running Casing

    I’m going to try and wrap this up in the next couple of days. It has gotten much more involved than I originally intended. I am by necessity leaving out a lot of details. If I included each and every step this thread would be 20 pages long.

    Ok. We have all the drill pipe out of the hole and stood back in the derrick. Now we will pick up, screw together and run in the hole the 9 5/8" casing with the float equipment.

    A truck brings out the cement and we install a "Cementing Head" in the top joint of casing. I measure all the casing and drill the hole to fit this measurement, so that the top of the last joint is just above the rig floor.

    The conductor pipe is cut off in the cellar. A pump is used to pump the drilling mud that returns out of the hole and into the cellar and pump it up to the shale shakers.

    A 2" steel line is attached to the cementing head and the cement is pumped down the casing. After the calculated amount is pumped then the cement head is removed and the plug is dropped. The cement head is put back on and either water or drilling mud is pumped to displace the cement. When the plug hits the float collar the pressure increases and pumping is stopped. The cement returns to the surface and we have 25# sacks of sugar to pour into it before we pump it out to the reserve pit. The sugar keeps it from setting up and cementing up the pump and lines used to pump it out of the cellar.

    The surface casing is the only time that we pump cement back to surface. The next string of casing, the intermediate 7", will be run inside the surface casing and run to about 7,200’. The cement will be calculated to come up only about 200’ inside the surface casing. The final string of casing will be run when the well is at final depth, around 9,500’ on this one. The production casing, 4 ½" will be run inside the 7" intermediate and the cement brought up to 200’ inside that. So in the end, every inch of open hole will be cased and cemented.

    After each string of casing we go to a smaller sized bit that will go inside the casing run. We start out with a 12 ¼" bit then run a 9 5/8" casing. Then we use an 8 ¾" bit and run a 7" casing. The final hole section is drilled with a 6 1/8" bit and cased with 4 ½" casing.
    The reason for this is to isolate different zones. The surface casing primarily isolates any water tables. The intermediate is usually stopped just short of drilling into any known, pressurized formations. The formations higher up the hole are generally softer and cannot take a high hydrostatic pressure. So the amount of mud weight that you can run is limited. If the mud weight, and thus the hydrostatic pressure, becomes to high the column of mud can be forced out into the formation. We call this lost circulation. Sometimes it results in no returns at all to the surface. This is costly as you are losing the mud you have been carefully building and it also reduces the hydrostatic pressure of the column on the bottom of the well. If you have a pressurized zone the hydrostatic pressure may not be enough to hold it down and this results in a blowout. The worst thing you ever want to happen on a rig.

    So by casing off the weaker zones above you it allows you to drill into your production zone with a much higher mud weight and hydrostatic head. I have been on wells where we ran as many as 5 strings of casing. We started out with a 36" casing and finished with a 3 ½".
     
  4. Minuteman

    Minuteman Chaplain Moderator Founding Member

    Wellhead

    After the casing is run and cemented we either cut off the casing in the cellar and weld on a wellhead or, in our case, we have a "Speedhead" which is already welded onto a "pup" joint of casing and is screwed into the string and lowered down through the floor until it sets on the cut off conductor pipe. After the casing is cemented a welder will tack weld the base plate of the wellhead onto the conductor pipe so that it cannot move.


    The landing joint is attached to the speedhead with a flange that is bolted on. This is removed and this leaves a platform to attach our blow out prevention equipment.

    The wellhead has a bowl inside it that the next section of casing will be landed into and locked down. Then the final string of casing will be landed on top of that and locked in and sealed.

    SPEEDHD.JPG SH.JPG
     
  5. Minuteman

    Minuteman Chaplain Moderator Founding Member

    BOP's

    The blow out preventers consist of four parts. All 4 sections serve to prevent any gas from coming up through the well bore and to the surface. If a gas influx or a "Kick" is taken the BOP’s seal off the well bore and allow us to control the gas bubble and to get it out of the well safely.

    The first section are two hydraulically controlled "Rams" that close when actuated. The ram blocks are on each side of the drill pipe and each has a half moon shaped notch in them. A heavy rubber lines the face of the blocks and when the hydraulic pressure forces them closed they encircle the drill pipe and are squeezed together to seal off the well.

    We use two sets of pipe rams and one set of blind rams. The blind reams are used if there is no pipe in the well. The face of the ram blocks are flat and the rubber seal compresses tight together and seals off the well.

    If the octagon Kelly was to be in the hole and you were unable to pick it up and out of the BOP’s then you have the "Annular Preventer" on the very top of the "Stack". This is basically a large, hard rubber doughnut, that when closed will seal around any sized pipe.

    The BOP's are picked up and put onto the wellhead and bolted down. Then we pressure test each section to make sure that they will hold.
    The closing unit is called the "Koomey" short for accumulator. It has a reservoir of hydraulic fluid and is pumped up to high pressure, 3000 psi, and when engaged it pushes the hydraulic fluid through the armour covered hoses to the BOP stack and to the rams, and annular.

    There is a remote unit for actuating the koomey from the rig floor.
    bop.JPG wh wbop.JPG nd bop.JPG p ram cls up.JPG p ram c up 2.JPG hydrill on grnd.JPG hydril on bop.JPG komy.JPG koomey.JPG remote.JPG
     
  6. Minuteman

    Minuteman Chaplain Moderator Founding Member

    Choke Manifold

    Once the pipe rams are closed around the drill pipe it prevents any gas or fluid from the well bore from coming up any further. An internal check valve at the bottom of the drill pipe prevents anything from coming up inside the pipe. So now we have the well "Shut In".

    But now we have to get the gas out of the well. There is a steel line with a valve on it that comes out of the BOP, underneath the rams, and goes out to a "Choke" manifold.

    The choke manifold is a bank of valves that allows us to divert the gas or the fluid to where we want it to go. On each side of the choke manifold is an adjustable "Choke" that allows us to squeeze the flow coming back from the well and hold a backpressure on the well. This backpressure increases the hydrostatic head and prevents any further gas from entering the well. We hold this backpressure while engaging the mud pump and circulating the gas bubble out of the well. At the same time we are increasing the weight of the drilling mud to a level that a formula has given us that will be heavy enough to hold the newly encountered pressure.

    The mud is coming up out of the well bringing the gas bubble with it, it hits the pipe rams and is diverted through the choke line to the choke manifold. From there it flow out to a "Gas Buster". This unit basically separates the gas from the mud. The mud falls out and flows through a pipe in the bottom of the gas buster and returns to the mud tanks. The gas is of course lighter and rises and flows out of a pipe in the top of the gas buster. It flows, under pressure down a flare line and to the flare stack. The flare stack rises up into the air about 30’ and has a propane fired igniter at the top. The igniter is lit and when the gas comes out it is burned, or "Flared" off.

    This procedure is one of the most dangerous and nerve racking things that we do. Any leak in a line and we would have gas seeping up all around the rig. The ram rubbers can fail and allow the well to flow unrestricted. When all is going well the gas is under such pressure that when it is roaring through the gas buster and out the flare stack it is as loud as a jet engine. The gas buster and the flare line are shaking and jumping from the pressure flowing through them. Notice the tie down lines on the flare stack.

    I’ve included a picture of a rig in Turkmenistan that had a blowout that got away from them. It didn’t catch fire but you can see the force that we deal with. The sand in the fluid coming out is like a cutting torch and will cut steel in two in minutes.
    chk lin t bop.JPG chk line to man.JPG choke man 1.JPG gas buster.JPG gas buster to shkr.JPG flare stack.JPG
     
  7. Minuteman

    Minuteman Chaplain Moderator Founding Member

    Blowout

    A blowout can be a real witch. These pictures prove it!!
    F00000c_034[1].JPG F00000c_026[1].JPG rotary[2].JPG Witch_Of_Turkminastan_In_Sky_1[1].JPG Witch_Of_Turkminastan_In_Sky_2[1].JPG
     
  8. Minuteman

    Minuteman Chaplain Moderator Founding Member

    Some more Blowout pics

    Things you don't want to see...
    BLOWOUT4aa. drill1411. DSC00010a. DSC00023a. DSC00036a. DSC00040ab. 2149252970062928585nGnCDu_pha. Picture_481_op_800x600. Pictures_From_Work_020_op_800x600.
     
  9. Minuteman

    Minuteman Chaplain Moderator Founding Member

    The weel is drilled

    So now the well is drilled, we pull the drill pipe and stand it in the derrick. A truck comes out with a wire line spool on the back. They run "Logging" tools into the hole on a thick wire line. The tools send an electrical signal up the line and to a computer in the truck that prints out a "Log" or an electronic picture of the entire well bore. This will be used to determine which zones to attempt to produce. The logging tools are removed from the well and the truck released. It may surprise you to know that the people drilling the well never know if it will make a good well or not. We never see oil. Unless we have a blowout and we don’t want to see that.


    The drill pipe is run back to bottom and then we come out laying down each joint. Then we run the production casing and cement it in.
    The BOP’s are taken off and the "Tree" is made up on top of the wellhead and the valve shut.

    Then the rig is rigged down. The derrick is layed over, taken off the floor and disassembled. The mud lines are removed, the mud tanks emptied and cleaned. Everything is loaded onto trucks and taken to the next well site.
    dht2.JPG dh tree.JPG dhtree vlv.JPG drk 1.JPG derk 2.JPG drk 3.JPG drk 4.JPG drk 5.JPG drk dwn.JPG crown on trk.JPG
     
  10. Minuteman

    Minuteman Chaplain Moderator Founding Member

    Producing the well

    After the drilling rig moves off the completion crews come in. they rig up a pole and a wire line truck and they run a "Perforating gun" into the hole. This is a long cylinder that is loaded with what amounts to rows of armor piercing shells. When the tool is lowered to the depth picked by the geologists after looking at the logs, then an electric signal is sent down the cable and the guns are fired. These rows of shells explode and shoot holes through the casing, the cement on the outside of it, and several feet into the formation.

    The casing is filled with a lightweight production fluid so the hydrostatic head is very small. The oil and gas in the formation flows into the casing and, if it is a free flowing well, it pressures up on the casing. The perf guns are removed from the well and the pressure is monitored.

    The first pics in this thread are of the last well that we drilled. We took a "Kick" on that well and I was on the choke for 4 ½ hours trying to kill it. We had a flame shooting out of the flare stack about 40 feet into the air. Notice how black the top of it is in the picture above. It wasn’t like that before that well.

    When they perfed that well it immediately had over 2000 pounds of pressure on it. They watched it for 4 hours and the pressure built up to over 4000 pounds.

    After the well is perfed and it is evident that it is going to be a good well then a production "Christmas Tree is made up on the well head. If it is a free flowing well. Under gas pressure so that the gas and oil will flow to the surface, then a separator is rigged up on location, a pipe line is ran to it, the separator does just that. It separates the gas from the oil. The gas is sent down the "sale" pipeline and eventually pumped to a receiving station. The oil is allowed to flow to a battery of tanks.

    A "Pumper" who works for the oil company comes out once a day and checks on the well. He "Gauges" the tanks to see how much oil has accumulated in them. When they start to get full he calls for a tanker truck to come out and empty them. The tanker hauls the oil to the refinery.

    The following pics show them Perfing the last well. They are a different division than drilling and I did not want to get in their way. You can see the long pole in the air that they run the wireline on. It has a sheave on the top and keeps the cable up and allows them the room to make up the perf guns. Perf guns can be as much as 30-50 feet long and shoot as many as 30 holes per foot.

    The next pics show a production tree and the tank batteries. The yellow boxes are where the tanker ties into the line running into the tank and sucks the oil out.

    There is only one more thing to explain. Some wells do not have the gas pressure to flow the oil to the surface. So small tubing is run into the well. Usually a 2 7/8" pipe. It has an anchor on the bottom that bites into the production casing and seats the tubing in the casing, just above the perfs. Then a double acting pump is run inside of the tubing. It is made up on a string of sucker rods. A sucker rod is a round piece of steel with a threaded pin on the bottom and a threaded box on the top about 20 ' long. They are screwed together and the pump is run to the bottom of the tubing. Another anchor on the pump seats it inside the tubing and a "Pump Jack" is rigged up. Everyone has seen these pump jacks going up and down. They are raising and lowering the sucker rod string. Each time the rods go up the pump pumps the oil upwards. Every time the pump goes down it is pumping also. It is a double acting pump. The oil is pumped up the tubing and through a pipe to the tank battery to await the tanker to take it to the refinery.
    perf.JPG christmas tree.JPG loc.JPG loc 1.JPG
     
  11. Minuteman

    Minuteman Chaplain Moderator Founding Member

    wrap up

    So there you have it. You now know more about the oil business than 90% of the general population. The next time you drive by, or see a rig on TV, you will know a little about what they are doing and why. And I would hope that you would think about the "Roughnecks" around the world, that work so long and hard in such remote and inhospitable places to bring that oil and that gasoline to you. It is a very dangerous profession. You will not find anyone who hasn’t themselves, or know someone who has, lost a finger, a toe, an arm, leg, eye, or hand. And you won’t get any ten together and not have at least one who knows someone who was killed on a rig.

    The IADC (International Association of Drilling Contractors) did an in depth decade long survey back in the 70’s. Some of the findings that they came up with were these;

    The oil industry, when rated not by the number of accidents, but by the severity per 100,000 accidents, came in at the #3 most dangerous profession.

    They found that the three most common factors among all oilfield workers were;

    <DIR>1) Alcoholism 2) Divorce and 3) a criminal record

    </DIR>Roughnecks are the last Gypsies. We traipse all over the world in the never-ending quest for black gold. We risk life and limb for it. Some of us get rich. Some of us die trying. Most of us just get by.

    My wife ( #3) tells me that she knows she comes second in my life. My mistress comes first. And she accepts that. She knows that my first love, my lifelong mistress, is the oilfield. And I will never leave her.

    Thanks for letting me share a little of my world with you.

    Roughnecks are proud of their rigs. Much like a sailor who is proud of the ship he serves on. So to wrap this thing up I will include some pictures of some rigs and the men who work on them.
     
  12. Minuteman

    Minuteman Chaplain Moderator Founding Member

    Rigs

    Rig pics
    100_0032a. Aquila_Rig_12_004a. cannon_12. craigo_s_pics_009a. DERRICK_PICTURES_168a. DSC00392a. DSC01044a. NABORS_DRILLING_334a. Pioneer_dilling_rig_55_1a. rig249a. rig_631_184a. VOYAGERa.
     
  13. Minuteman

    Minuteman Chaplain Moderator Founding Member

    Roughnecks

    Hands
    100_0462a. C___L_Services_Roughnecksa. Derrick. fh2. floorpatta. IM000370. Mvc_007fb. Patterson_506__1_a. Patterson_506__2_a. Patterson_506__3_a. unit_310_2a. vin_floora.
     
  14. Minuteman

    Minuteman Chaplain Moderator Founding Member

    Slogans
    9. 8. 3. 5. 1.
     
  15. ghrit

    ghrit Bad company Administrator Founding Member

    MM, a good read. The pix of drill rigs show there is some beauty in rough businesses. And I fully understand the addiction to that sort of work, being a construction stiff myself. (I notice there aren't a lot of fat roughnecks --)

    A real construction hand gets itchy feet every 18 months or so. There are only two good projects, the one you just finished and the one you're moving to.

    Thanx.
     
  16. Minuteman

    Minuteman Chaplain Moderator Founding Member

  17. ghrit

    ghrit Bad company Administrator Founding Member

    Neat tune, alright --.
     
  18. Minuteman

    Minuteman Chaplain Moderator Founding Member

    I wish I would of had this when I was creating this thread. It is a free downloadable book on oil and gas production. A basic from the ground up (or down) primer that is great for anyone not familiar with the process.
    I thought it would be of interest especially to our resident engineer.

    http://www.itk.ntnu.no/ansatte/Onshus_Tor/Oil%20and%20gas%20production%20handbook%20ed1x3a5%20comp.pdf

    also I was looking back over these pics. That rig I was on then is a dinosaur. I will post some pics of some of the more modern rigs I worked on after that one.
     
  19. Minuteman

    Minuteman Chaplain Moderator Founding Member

    Not the stand on your feet in the rain, snow, and heat for hours like in my day!
    IMG_0159. 200707023. RIG 008.
     
  20. ghrit

    ghrit Bad company Administrator Founding Member

    The new ones can turn the bit with a mud motor rather than turning the drill stem. They are using some of those up here in the Marcellus gas play, so I'm told. (Still haven't figured out how they steer either type, much less know where the bit is.)
     
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