Question

a) Explain the major causes of kick as related to the well control.

b) There are two major methods usually used in killing the well "the driller method" and "wait and weight method." Suppose that you have the following situation. Which method you will choose. Explain and justify your answer. ​​​​

• Shortage of crew members for mixing.

• Shortage of heavy material (Barite) to prepare a kill mud.

• Un-skillful people to do a complicated calculation.

• Time is not crucial.

  

c) What do you understand from the following terms used in the well control:​

i. Secondary well control

ii. Dynamic Bottom hole pressure

iii. Circulating pressure

iv. Kick warning signs

d) While drilling a well, a kick was detected at 10100 ft depth, the driller immediately closed in the well and recorded following data was data:

Hole diameter = 8 1/2 inch

Mud weight = 13.2 ppg

Shut in drill pipe pressure (SIDPP) = 530 psi

Shut in casing pressure (SICP) = 800 psi

Pit gain =14 bbls

Assuming that the slow pump rate @30 SPM = 360 psi and the

Annular pressure loss (APL) = 210 psi

Calculate each of the following:

i. Dynamic hole pressure (DHP)

ii. Killing mud weight (KMW)

iii. Equivalent circulating density (ECD)

iv. Maximum allowable annular surface pressure(MAASP)

  

Answer 1

a)What is kick?
A kick is a well control problem in which the pressure in the drilled rock is higher than the mud hydrostatic pressure acting on the rock face.
Causes of kick in well control
The causes of kick are:

1.Insufficient mud weight
2.Lost circulatiomu
3.Swabbing.
4.Cut mud.
5.Shallow gas sand

1.Insufficient mud weight.
The kick can be detected when drilling through a permeable zone which has a higher pressure than the pressure exerted by the mud column. If the overpressure zone has low permeability, then traces of the formation fluids should be detected in the returns. If the permeability is at a high level, then the risk is greater and the well should be shut-in just after getting the flow during the flow check.
2.Lost circulation
A kick occurs from lost circulation, large volume of kick fluid may enter the hole before the rising mud level is observed at the surface. It is suggested that the hole be filled with some type of fluid to monitor fluid levels if lost circulation occurs.
3.Swabbing
Swabbing is the reduction of bottom hole pressure below the formation pressure due to the effects of pulling the drilling string which allows formation fluids to enter into the wellbore.
4.Cut mud
Gas-contaminated mud may also cause kick. The density reduction of mud is usually caused by fluids from the core volume being cut and released into the mud system. As the gas is circulated to the surface, it expands and may reduce the overall hydrostatic pressure causes kick.

5.Shallow gas sands
Kicks from shallow sands mainly from gases and water, whilst drilling in the top hole section with short casing strings can be very hazardous.Kicks from shallow sands are caused by charged formations.The main causes of charged formations are
Poor cement jobs, Casing leaks, Injection operations, Improper abandonment, Previous underground blowouts etc.