drilling methods in petroleum industries

 Drilling methods

          There are two main method for 

              drilling . These are given below:

         1: Cable tool drilling method.

         2: Rotary drilling method.

   1: Cable tool drilling method:

         Cable tool drilling is one of the

oldest cutting actions utilized in the

drilling industry developed in China

over 4000 years ago the cable tool is

tried-and-true responsible for millions

of successful wells around the world

this system is still used today because

of its own unique advantages which

include one-person operation low

equipment cost compared to other systems

simple rugged design requiring minimal

maintenance low horsepower requirements

of this rig and finally cable tools have

proven to be virtually indestructible

these machines are mainly used today for

drilling and unconsolidated materials

and soft rock formations where

relatively shallow depth wells are

required approximately 100 feet or less

slow penetration rates are

characteristic of this drilling system

support equipment required for this

drilling process are basic a small truck

with welding equipment torches and a

small amount of makeup water a

separately mounted deck engine powers

the rig the cable tool uses the

percussion cutting action utilizing a

1200 pound drill string and usually a

carbide button bit this bit goes up and

down once per second performing four

important drilling functions at once

penetrating the material beneath the bit

reaming the sides of the hole crushing

the geology into fine particles and

mixing these cuttings with water

the drilling action in conjunction with

approximately five gallons of introduced

water mixes with the cuttings which

require baling after approximately four

feet of drilling this flushing system

requires the drill string to be tripped

out of the hole and the baler to be

tripped into the hole the baler is

simply a hollow tube with a check valve

on the bottom which fills with the

cutting slurry mixture the action of the

dart valve enables the baler to collect

cuttings for ID and recording purposes

as per regulation 9:03 as well as

removing accumulating cuttings by

dumping them in the mud spunk the baler

is also useful for measuring approximate

water pumping rates and levels at any

time during the well construction the

cuttings from the borehole are usually

well mixed and small in size

representing an accumulation of the

formations encountered since last bail

the cable tool drillers have developed

the ability to interpret the feel of the

drill stream to improve well log

accuracy and in identifying aquifers the

cable tool drilling process typically

consists of drilling removing the

cuttings identifying the geology

monitoring the water flow if present and

then advancing the casing there are two

methods for casing advancement the drive

cap and the drive blocks the drive cap

is primarily used by cable tool

operators until such time is increased

friction is encountered

the drive blocks that enable more energy

to be transferred to assist with driving

the casing down the casing advancement

continues in overburdened situations

until such time as a suitable aquifer is

encountered or until the casing is

firmly seated in bedrock

after which casing is no longer required

as the geology itself or rock stabilizes

the hole the large bowl reel shown here

supports the cable which in turn

supports the drill string the speed at

which it is turning here is typical of

hole advancement in unconsolidated

material ideally casing is added in

10-foot sections to improve efficiency

additional casing sections are usually

welded ensuring a watertight seal as

required per regulation 9:03

the annular space between the working

casing and the permanent casing is

commonly grouted after borehole

construction.