What is the objective of drilling rig?

We have discussed the components of the drilling rig, now let’s discuss the drilling process itself. An oil or gas well is drilled in a very ordered sequence. The steps in this sequence are almost universally applied to the drilling of all wells.

1. Plan the Well: As we have discussed, exploration well prospects are generated by exploration geologists; while development wells locations and objectives are generated by development geologists. Once the surface locations and well objectives are known, the geologists work with the drilling engineers to develop the detail drilling proposals. In addition, all permits (environmental, safety, regulatory, etc.) are acquired during the final stages of the planning process when a solid well proposal is developed.
2. Perform Shallow Gas Survey: To ensure there are no shallow gas hazards which may result in a kick or blow out, a shallow gas survey is performed to identify the locations and depths of any potential shallow gas hazards. Preliminary surface locations and well trajectories may be altered from the original well proposal to avoid these shallow gas hazards.
3. Prepare the Wellsite: The site preparation involves building clearing land for use by the rig, building access roads to the well site or well pad, construct infrastructure for water, water disposal, and electricity, dig and line all mud pits to prevent ground water or water table contamination, dig reserve pits for cutting storage (for eventual disposal), and drill the holes which will eventually become the rat hole and the mousehole. The site preparation may involve multiple contractors and companies to perform all of the required work. As we discussed in earlier lessons, a lot of site-preparation time and the environmental footprint can be minimized if multi-well pads are used in the field development.
4. Set the Conductor Casing: Prior to the arrival of the drilling rig, an Auger Unit (in hard rock regions) will drill a large diameter hole capable of accommodating 18 in. to 36 in. conductor casing (see Figure 9.16). In soft rock regions or at offshore locations, a diesel hammer may be used to hammer the conductor casing into place. The conduct casing may go to depths of 40 to 300 ft depending on the location. The conductor casing is typically set through the top soil and loose rocks to the bed rock. The objective of the conductor casing is to isolate the wellbore from the top soil to ensure that loose debris does not enter the well during early drilling operations. The conductor casing is then cemented into place.
5. Move-In and Rig Up (MIRU): Once the wellsite is prepared and the conductor casing is in-place, the rig is brought on location. Most land rigs, particularly those in North America, are transported on multiple trucks. Once on the well site or well pad, the rigging-up process begins. Rigging up the well consists of taking the rig modules from the trucks and assembling the rig. Included in the rigging up process is setting-up all of the rig systems and testing these systems. Here is a YouTube video, "Rigging up Land Drilling Rig" (3:35), showing the Rigging Up process of the derrick:

   Source: Industrial3D Inc | I3D

   Pioneer Drilling 60 Series Rig-up Animation | Drilling Animation | Land Rig Animation | Oil & Gas. This video contains only background music with no words.

   
   Transporting and assembling the rig may take 50-75 workers (two crews), 35 – 40 vehicles, and take up to four days. If a multi-well pad is used, once the rig is rigged-up for the first well, then the rig can simply be skidded over to the next location without having to dig-down.

6. Spud the Well: After the rig has been inspected and all of the systems tested the well can be Spudded. Spudding a Well refers to starting the rotary drilling operations for that well.
7. Drill Down to the Surface Casing Depth: The first section of the well to be drilled is the section that goes down to the pre-determined surface casing depth (Casing Point). Obviously, for this section of the wellbore, the drill bit diameter must be smaller than the ID (inner diameter) of the conductor casing. In this shallow section of the wellbore, fresh water aquifers (both for personal and municipal use) exist. As discussed earlier, shallow gas hazards may also exit. The objectives of drilling this first section of the well is to allow the setting and cementing of the surface casing to:
   1. protect the fresh water aquifers by placing a steel and concrete barrier to isolate the water table from the well;
   2. protect the well from the aquifer (cutting of the drilling fluids with fresh water);
   3. protect the well from shallow gas hazards.
   This section of the well is drilled through the most environmentally sensitive depths. Consequently, when this section of the hole is drilled, it is typically drilled with the most environmentally friendly drilling fluid (possibly either air or fresh water) and cased and cemented as soon as possible to alleviate any potential of contaminating fresh water aquifers. By running the surface casing string, we are putting the environmentally sensitive water table behind pipe and protecting it from future well (drilling and production) activities.
8. Run and Cement the Surface Casing: Once the surface casing point is reached, the surface casing is run into the wellbore and cemented into place. This process is performed by:
   1. Pulling Out of Hole (POOH): Tripping out of the hole with the drill pipe to remove it from the wellbore during cementing operations;
   2. running the surface casing;
   3. pumping a cement slurry down the interior of the casing;
   4. chasing the cement with drilling fluid to displace the cement up into the annular space between the casing string and the wellbore (rock);
   5. allowing time for the cement to Cure (harden).
   Cementing is a common activity planned and implemented by drilling engineers, and you will learn a lot more of the details in your future drilling courses. The following YouTube video, "Running Casing" (7:01), shows the cementing process (note: this is a commercial video for Frank’s International):
    

   The BOP is then installed on the surface casing string.

9. Continue this Process to Drill to the Next Casing Point: This drilling process is continued to the next pre-determined casing point. The selection of these intermediate-string casing points is beyond the scope of the class, but the criteria are based on the mud weight, the Fracture Pressure of the formations to be drilled (the pressure that causes the formation to fracture), the locations of any Lost Circulation Zones, and the locations of any High Pressure Zones. As we discussed earlier, any of these situations may result in a kick and a potential blowout. The objectives of the intermediate casing strings are:
   1. isolate unstable hole sections behind pipe;
   2. isolate lost circulation zones behind pipe;
   3. isolate under-pressured zones behind pipe (prevent lost circulation);
   4. isolate over-pressured zones behind pipe (prevent a kick);
   5. isolate multiple producing zones
10. Continue this Process to Drill to each Casing Point: This process is repeated for each of the planned casing points. Obviously, as successive casing strings are run and cemented into place, smaller diameter tools and drill bits must be used for continued drilling operations. As we discussed earlier, the two most important drilling parameters within the Driller’s control to maximize the Rate of Penetration (ROP) of the drill bit are the weight-on-bit and the rotational speed of the rotary system in Revolutions per Minute (RPM).
11. Continue this Process to Drill to Total Depth (TD): Once the final intermediate casing string is run and cemented, the drilling process is continued until the well reaches the TD (Total Depth) of the well. At this point, the well is said to be TD’ed.
12. Log the Well with Open-Hole Logs: At this point, the sand face is exposed to the well and Open-Hole Logging Tools can be run in the well. Open-hole logs are used to measure certain properties of the subsurface formation that are of interest to the geologists and engineers working on the well and the reservoir.
13. Run and Cement the Production Casing String or Liner: If a production casing string or production liner is to be used in the completion, then they are run and cemented at this time.
14. Compete the Well: Install the well completion as discussed in earlier lessons:
    1. tubing
    2. gravel packs
    3. packers
    4. sliding sleeves
    5. stimulation
       1. acidize the well
       2. hydraulically fracture the well
    6. artificial lift
15. Rig Down and Move Out

Figure 9.16: Typical Hydrocarbon Production Well with Multiple Casing Strings including two Intermediate Casing Strings

Source: Greg King © Penn State, licensed CC BY-NC-SA 4.0

Finally, here is a YouTube video, "Drilling Animation" (5:58), showing the entire drilling process. This animation is from Chesapeake Energy, and it discusses the drilling process for a Marcellus Shale well:
 

Water well drilling rigs are generally used to complete drilling, pipe installation, well flushing, etc.The purpose of water well drilling rig is to reach an aquifer or water source deep below the ground.The final purpose is to find a clean water source. 

Preparations:First of all,water well drilling rigs is an equipment .You can choose type according to your need.Like truck water well drilling rig CSD600,CSD800 and trailer water well drilling rigTWD300,JXY200 etc. We have a lot of different type.In the normal situations,water well drilling rigs must be transported to the site by truck.

For example the CWD1000 and CWD1200 that we are selling.They are muti-functional,CWD1200 is a centralized control machine, and the centralized console is suitable for various operations and controls.Then you can use multifunctional underground water detector to find the place that where can be drill.If you don’t have it,you can buy UPE1000 and UDE2000 that we are selling.They can all stick to deeper places and bear greater pressure.After that you can lower four outriggers and you must make sure it is stable.Because if it is not,it may cause work operation stop or other dangerous accidents.The key point is check if there is petrol in the fuel tank.Then check if the drilling rig parts are secure, clean the water well drilling rig equipment and surrounding debris.

Work ways:There are two common ways of drilling holes.One of them is mud drilling.This way need a mud pump,you can choose BW320  BW200,and other mud pump that in our company website,usually this way need to gear with a roller drill bit.When the machine is on working,water or mud are transported into the borehole,that can cooling the drill bit and can remove rock powder, protect the borehole wall and block leaks.

Another way is air drilling, like mud drilling it needs to gear with a machine which is an air compressor. Like HG700-18 etc. We also can provide this kind of product.. This drilling method operates the DTH hammer according to compressed air by air compressors. It also plays a role in cooling the drill bit and bringing rock debris out of the hole from the bottom. 

Do you want to know more knowledge about drilling rig？Contact us if you need them,we will provide high-quality service for our customers.We can also recommend products based on your needs.