Before the introduction of drilling engineering, several terms will be stated below:
Drilling rig: the working platform above the well, where contains main components for drilling activity
Drilling pipe: steel made pipe used to do the drilling work
Casing: steel made pipe used to isolate the well from communicating with down hole rocks
Tubing: small size pipe used as production pipe
BOP: blowout preventer, multi-valve equipment used to prevent the blow out of formation fluid
Bit:
Cuttings: rock fragments need to be circulated to the surface
Drilling fluid: man-made mud used to circulating cuttings to the surface
After these preparations, a brand new well can be drilled. The overall scenario of this job can be simply described as three main parts. Drilling, circulating, and completing.
It is easy to understand the drilling part which drill pipe is lowered from the drilling rig into the well to penetrate rock formations. As the drilling progressed, cut rock fragments need to be brought to the surface, this is the so-called cuttings. It is very important to circulate these cuttings out of the well, otherwise the further drilling process will be hindered by those fillings. A common oil production well will have a depth about 10000-20000 feet, and this length will be finished in separate sections. After finishing each section, casing will be lowered and cemented, therefore the hole could be protected from well wall collapse. After the casing being fixed, another hole section with small hole size could be drilled.
When the whole length finished, another job will be carried out, which is called perforation. A special gun will be lowered to the objective section where has oil and gas indications. Bullets projected from the gun will penetrate the pipe wall, then the formation and well bore are communicated. Oil and gas can be produced now.
After
determining
to explore an oil
field, drilling engineers will start to plan drilling test wells, which
are
called the wildcat. If wildcat wells provide a good oil distinction,
further
test wells could be drilled to determine the area of this field, these
wells
are called step out. After the area being determined, massive
production wells
can be drilled.
There are several preparations should be done before drilling:
1. Obtain drilling permission from local government
2. Building roads to the well location
3. Transporting drilling equipments and crews
4. Prepare materials required to drilling program