Once the rig is set up and the surface casing is cemented in place to protect the local water table, the real drilling begins. There are different size rigs that drill to different depths. The drilling time varies depending on the depth of a well, the type of formations that must be drilled through, and any complications that might arise. Seldom will a well be drilled without some complication, but these are anticipated and seldom do more that slow down reaching total depth by a few days.

Drilling Rig at night

Drilling rig in daylight

The drilling of a well is done within a closed system. The drill bit chews up rock as it moves down deeper into the ground. As it chews up rock, the drilling fluids, or “mud,” flows down the drill stem and out the holes at the end of the drilling bit. This provides lubricant for the drill head, and as the fluid moves back up the outside of the drill stem it carries rock chips to be deposited in the cuttings pit. The water is remixed with drilling compounds that create the drilling mud that then goes downthe drill stem again and out the end of the drilling bit. As the well is being drilled, the drill bit will approach known oil and gas zones and will anticipate the pressures common to the area for those formations. The pressure of that formation will be counterbalanced by increasing the thickness of the drilling mud so it can hold back the pressure of the oil or gas zone.Tripping is another term that will be heard discussed during the drilling process. Tripping occurs when a drill bit has been worn down enough to be ineffective. To replace the drill bit, every joint of drilling pipe must be removed so that the drill bit can be changed on the end of the drill stem. This is a time consuming process and can take half a day or more.Once the well is drilled, there is a naked hole, uncased, full of drilling fluid that counter balances any pressure from oil and gas zones. It is time to test the well. A decision will be made whether to case the
well and attempt to put it into production, or to plug and abandon the well.

Drilling Mud Circulation

The steps involved in adding a joint of drill pipe to the drill string as the hole deepens

Monkeyboard

Tripping for a Drill Bit

Adding a joint of pipe

Drill Pipe Laying on Pipe Rack

Catwalk and Pipe Ramp

Blowout Preventer

Mud and Chemical Sacks

Mud Return Line and Mud Pit