Mud Filter Cake

Mud filter cake is a layer formed by solid particles in drilling mud against porous zones due to differential pressure between hydrostatic pressure and formation pressure.  For the drilling operation, it is preferred to have a filter cake that is impermeable and thin. Practically, the filter cake from API or HTHP fluid loss test should be less than or equal to 1/16 inch. If drilling fluid is not in a good shape, which results in a thick filter cake in the wellbore, it will lead to a stuck pipe situation and high torque/drag.

Mud filter cake

Mud Filter Cake from HTHP Fluid Loss Test (

How will the filter cake impact on a drilling operation?

Differential sticking

If mud filter cake is thick, a contact area between drilling string or any kind of tubular will be increased. When drilling into permeable zones that are severely overbalanced, the drill stem will have high chance to get differentially stuck across these zones.  Moreover, not only can the drilling string get stuck, the logging tool could be stuck across the permeable sands as well.

Torque and drag

Under dynamic conditions such as drilling, working pipe, etc., if drilling mud has a thick filter cake across the wall of the wellbore, torque will increase.  Furthermore, a thick wall filter cake will result in high drag while tripping out of the hole or logging.


Andy Philips, 2012. So You Want to be a Mud Engineer: An Introduction to Drilling Fluids Technology. Edition. CreateSpace Independent Publishing Platform.

Ryen Caenn, 2011. Composition and Properties of Drilling and Completion Fluids, Sixth Edition. 6 Edition. Gulf Professional Publishing.

Related Post

pH in Drilling Mud (Water Based Mud) pH is a value representing the hydrogen ion concentration in liquid and it is used to indicate acidity or alkalinity of drilling mud. The pH is presen...
Mud Weight and Its Importance in Drilling Mud weight or mud density is a weight of mud per unit volume. It is one of the most important drilling fluid properties because it controls formation ...
Water Phase Salinity of Oil Based Mud Water phase salinity is a factor showing the activity level of salt in oil based mud. In order to control the water phase salinity, salt is added into...
Pm, Pf and Mf of Drilling Mud (Water based mud) Pm, Pf and Mf are values indicating the alkalinity of drilling mud and the following is meaning of each value. Pm Pm stands for “phenolphthalein end...
Share the joy
  • 273
Tagged , , , , . Bookmark the permalink.

About DrillingFormulas.Com

Working in the oil field and loving to share knowledge.

Leave a Reply

Your email address will not be published. Required fields are marked *