Gel Strength

The gel strength is the shear stress of drilling mud that is measured at low shear rate after the drilling mud is static for a certain period of time. The gel strength is one of the important drilling fluid properties because it demonstrates the ability of the drilling mud to suspend drill solid and weighting material when circulation is ceased.

How can we get the get strength?

We use the 3-rpm reading which will be recorded after stirring the drilling fluid at 600 rpm from a rheometer. Normally, the first reading is noted after the mud is in a static condition for 10 second. The second reading and the third reading will be 10 minuets and 30 minutes, respectively. You may wonder why we need to record the 3-rpm reading after 30 minutes.

The reason is that the 30 minute-reading will tell us whether the mud will greatly form the gel during an extensive static period or not. If the mud has the high gel strength, it will create high pump pressure in order to break circulation after the mud is static for long time. Furthermore, increasing in a trend of 30-minute gel strength indicates a build up of ultra fine solid. Therefore, the mud must be treated by adding chemicals or diluting with fresh base fluid.

The following causes will result in the high gel strength in the water base mud.

• Bacteria

• Drill solid

• Salt

• Chemical contamination as lime, gypsum, cement, and anhydrite

• Acid gases as Carbon Dioxide (CO2), and Hydrogen Sulphide (H2S)

For an oil base drilling fluid, there are several points that will cause the high gel strength in the mud system as follows.

• Over treatment with organic gelling material

• Build up of fine solid particles in the mud

Reference Books: Drilling Fluids Book

10 comments… add one
  • mohammed almusheti Jan 24, 2011, 2:53 am

    in the first i want to thank you for every thing that you helped us in drilling fluid
    Secondly i want advice from you to me Iam still younger eng in mud and recently i changed my job to safety eng .first what is your openion and how can i collect between two jobs not as work but as collect informations because in my first job first job i didn’t have good chance to become good in mud that reason made me to change my job my friends always say we think you will become excellent in mud but now i want to become expert between two jobs .

    • admin Jan 24, 2011, 8:47 pm

      If I were you, I would work as a safety engineer for few more months. Then you can compare which one you like. I recommend you to chose what you like instead of trying to be a mud engineer and a safety man at the same time.

      You can read and understand the mud but you need time on the rig to see the real operation. More you work, more you will be expert.

      I wish my recommendation would help you.

      Regards,
      Rachian J.

    • admin Jan 24, 2011, 8:47 pm

      If I were you, I would work as a safety engineer for few more months. Then you can compare which one you like. I recommend you to chose what you like instead of trying to be a mud engineer and a safety man at the same time.

      You can read and understand the mud but you need time on the rig to see the real operation. More you work, more you will be expert.

      I wish my recommendation would help you.

      Regards,
      Rachian J.

  • Mohamed Emam Apr 23, 2015, 3:39 pm

    thank you for this great info , i have a question please you said that we measure gel after 10 sec , 10 min , 30 min have we make the spinner rotate continually and take reading or we leave mud static for 10 sec then take reading then 10 min static then take reading ….etc ????? ,

    • Vineet Soni Jul 27, 2015, 1:31 pm

      Keep it static for that much amount of time.
      Then after the passage of required amount of time again start rotating it at 3rpm and take the reading at that instance.

  • Mohannad Jul 26, 2015, 6:48 am

    thank you sir for this beneficial information, any way, would you please telling me what the optimum gel strength value which has to be controlled why drilling in both OBM & WBM. value @10″/value@10’=?
    best regard sir

    Mohannad Al yazgi
    drilling supervisor

  • Mohannad Jul 26, 2015, 6:49 am

    sorry,
    while drilling

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