TECHSHORE INSTITUTE FOR DRILLING TECHNOLOGY

Techshore Institute for Drilling Technology is an initiative of the leading professional & reputed training brand of Techshore Inspection Services, which is having training centres all over Kerala. Techshore, offers courses in Drilling Technology from early 2015 and successful in providing placements for all those candidates in reputed companies with attractive salary packages and perks. 

Types of Pressure Involved in Drilling

Formation pressure

The pressure exerted by the fluid that get ‘s trapped inside the formation rock is known as formation pressure. Depending upon the formation pressure gradient, it is classified into two pressures: -

Normal formation pressure

Abnormal formation pressure

Normal formation pressure

By the deposition of rock layer over one other, water from the formation is squeezed out of the pores due to overburden, this phenomenon is called as compaction. As the formation water escape through the formation rock, it formation pressure also changes down to a normal value. mostly accepted normal value is ranging from 0.433 psi/ft to 0.465 psi/ft. Thus, the pressure within this range is known as normal formation pressure.

Abnormal formation pressure

The formation pressure which ranges from the normal value, i.e. 0.465 psi/ft is known as abnormal formation pressure. It is caused because of the reason that due to the overburden of formation water is formation rock tries to escape, loss by the impermeable formation that does not allow its normal escape, hence abnormal formation pressure is formed. The cause of abnormal pressure is due to.

1. Under compaction
2. Artesian effect
3. Faulting
4. Salt dome
5. Gas cap effect
6. Charged sands

Hydrostatic pressure

The pressure exerted on the formation to overcome the formation pressure by a static column of mud is known as hydrostatic pressure. Hydrostatic pressure is maintained by the density of mud. The hydrostatic pressure of the mud depends upon the true vertical depth of the well and mud density. Hydrostatic pressure is expressed in psi.

Hydrostatic pressure = tvd (in ft) * mud density (ppg) * 0.052

Where, 0.052 is the conversion constant

Pressure gradient

When the pressure of a fluid is calculated for a given unit length it is known as pressure gradient. The pressure gradient is the product of mud density (in ppg), conversion factor and unit length.

Pressure gradient = mud density (in ppg) * unit length (in ft) * 0.052

Swab and surge pressure

When the drill string is lowered for drilling purpose or the at the time of tripping in, the string exerts a pressure on the mud column, this is known as surge pressure. Surge pressure is always taken as +ve.

When the drill string is raised during drilling purpose or at the time of tripping out, the string loses a pressure on the mud column, this is known as swab pressure. Swab pressure is always taken as –ve because there is a loss of pressure.

Bottom hole pressure (bhp)

"Bottom hole pressure is defined as the sum total of all the pressure that acts on the bottom of the hole.

Bhp = hydrostatic pressure + surface pressure +/- dynamic pressure

Dynamic pressure is the pressure exerted by the pipe movement, i.e. swab or surge pressure or either due to fluid movement, i.e. by annular pressure losses.

Bhp during different Well operations:-

During drilling

Bhp = hydrostatic pressure + annular pressure losses

When not circulating

Bhp =   hydrostatic pressure due to mud column

While tripping in

Bhp = hydrostatic pressure + surge pressure

While tripping out

Bhp = hydrostatic pressure – swab pressure

Maximum allowable annular surface pressure (MAASP)

Maximum allowable annular surface pressure is defined as the maximum pressure at the surface that a casing can hold with complete safety.

Techshore - Scope Of Drilling Technology

A drilling engineer develops, plans, costs and supervises the operations necessary for drilling oil and gas wells. They are involved from the initial well design to testing, completion and abandonment.

Techshore - Career Objective

Seeking the position of Drilling Engineer that will utilize my skills and expertise in off-shore and on-land drilling operations for the development of the company. 

Techshore - Skill

Skilled in cased-hole electric line applications.