What is bottom hole assembly in drilling?
The Bottom Hole Assembly (BHA) is a key component of the drilling system, consisting of various components and tools (including the drill bit itself) which operate at the bottom of the wellbore and physically drill the rock.
Is drill bit part of BHA?
The drill bit is located at the very end of the BHA. The role of the drill bit is to transform the solid rock in the well path into rubble that is removed by the drilling fluid.
What is a BHA component?
The bottom-hole assembly (BHA) is the component of the drill string that includes the core bit, outer core barrel, various subs, and the drill collars.
Which of the following component is used at the bottom of the BHA to provide weight on bit and rigidity?
The medium collars add weight to the BHA and reduce ever-present flexure stresses between large collars and drill pipe or other tools of less rigidity than the large collars. Both may be used for jarring weight. Short Drill Collars: Short drill collars (SDC’s) are also called pony collars.
How long is drill pipe?
It comes in a variety of sizes, strengths, and wall thicknesses, but is typically 27 to 32 feet in length (Range 2). Longer lengths, up to 45 feet, exist (Range 3).
What is bottom hole pressure?
Bottom hole pressure is the pressure at the bottom of the hole, usually measured in pounds per square inch. In a flowing well the bottom hole pressure is equal to the pressure drop in the tubing plus the wellhead pressure. The reservoir or formation pressure at the bottom of the hole is known as bottom hole pressure.
What is a whipstock for drilling?
(Extractive engineering: Field development, Drilling) A whipstock is a curved steel wedge which is put into the borehole to start off the drilling of a new branch. Lateral deflection of the wellbore has been achieved by placing a wedge or whipstock in the well.
How many types of BHA are there?
three types
There are three types of BHA configurations. These configurations addressed are usually concerned with the use or layout of drill collars, heavy weight drill pipe and standard drill pipe.
How many types of BHA are there in drilling?
In general there are three types of Bottom Hole Assembly BHA In drilling: Slick BHA Type. Pendulum BHA Type. Packed BHA Type.
What are the components of a bottom hole assembly?
The drilling bottom hole assembly (BHA) is one of the components of the Drilling String which is below the Drill Pipes. The most common components of the BHA are Drill Collars, Stabilizers, Shock Absorbs, Jars, Reamers, Heavy Weight Drill Pipe, and The Drilling Bit.
How is drill pipe length measured?
The sensor is mounted in a collar at the top and continually measures the distance to the platform until the process is complete. Laser sensors measure the real time length of each pipe as it is drilled into the ground. The length measurement of the pipe is used to measure the total depth the pipes are into the ground.
What is a bottomhole assembly?
Figure-1: Schematics of bottomhole assembly [These bottomhole assemblies are designed for drilling a straight hole (left ) and a directional hole (right)]. than a drill pipe. Since the drill collars have such a large wall thickness, tool joints are not necessary and the connection threads can be machined directly onto the body of the collar.
What is a slick bottom hole assembly?
This type of bottom hole assembly (slick BHA) consists of a Drill Bit and Drill Collar without Stabilizer. Slick BHA is suitable for formations which have mild crooked hole tendencies. Slick bottom hole assemblies are seldom. As there are no expensive components on this type of BHA, It is more easier to fish such BHA.
What are the disadvantages of the bottom hole assembly BHA?
If the Weight On Bit (WOB) increased, the hole angle will increase and the opposite is true. The main disadvantage of the pendulum Bottom Hole Assembly BHA is that the Stabilizer must be placed within a few feet of a definite position obtained from the charts.
What should I do when the bottom-hole assembly reaches the surface?
When the bottom-hole assembly reaches the surface, the RCD packer must be removed or the annular preventer opened. The pressure gauge may be inaccurate, so a bypass to the annulus should be opened to check that there is no flow or pressure (note also the following discussion on Pipe Light).