Gel Strength by jarjis Experiment Number 6: Gel Strength. Koya University. Faculty of Engineering. Drilling Lab Supervised By Muhammad Jamal ============= This a report about Gel Strength. written by Jarjis Muhammad, Petroleum Engineering Dep. Koya University. For more Information please contact me: www.facebook.com/Jarjis.shaqlawaee

1. Petroleum engineering
Faculty of
Engineering
Koya University
Drilling Engineering
Laboratory
Experiment No. 6
Gel Strength
Date: Mar. 01th
2018
Supervised By: Prepared By:
Mr. Pishtiwan Jarjis Muhammad
Mr. Muhammad Group: B

2. Gel Strength Jarjis Muhammad
Contents:
Subject Page
Aim 3
Theory 4
Introduction to
Experiment
5
Calibration 6
Procedure 7
Calculation 8
Discussion 9
References 11

3. Gel Strength Jarjis Muhammad
Aim of the experiment:
Determine Gel strength (Rheology properties) by using VG
meter for 10 sec, 10 Min, 30 min, and 16 hours.

4. Gel Strength Jarjis Muhammad
Theory:
Gel strengths, 10-second and 10-minute, measured on the VG
meter; indicate strength of attractive forces (gelation) in a
drilling fluid under static conditions. Excessive gelation is
caused by high solids concentration leading to flocculation.
Signs of rheological trouble in a mud system often are reflected
by a mud’s gel strength development with time. When there is
a wide range between the initial and 10-minute gel readings
they are called “progressive gels”. This is not a desirable
situation. If initial and 10-minute gels are both high, with no
appreciable difference in the two, these are “high-flat gels”,
also undesirable. The magnitude of gelation with time is a key
factor in the performance of the drilling fluid. Gelation should
not be allowed to become much higher than is necessary to
perform the function of suspension of cuttings and weight
material. For suspension “low-flat gels” are desired.

5. Gel Strength Jarjis Muhammad
Introduction to Experiment:
Mud Container
Multi Rate Viscometer (Fann VG viscometer) Stopwatch

6. Gel Strength Jarjis Muhammad
Calibration:
1-we use a fluid which is called calibration fluid.
2-After putting the calibration fluid into the internal cup and
lifting it up by locking mechanism we read the RPM.
3- By the chart we have we can indicate whether we should edit
manual rotation of sleeve to read the right number or not.

7. Gel Strength Jarjis Muhammad
Procedure:
Gel Strength Measurement Procedures
1- Stir a sample at 600 RPM for about 15 seconds.
2- Turn the RPM knob to the STOP position.
3- Wait the desired rest time (normally 10 seconds or 10
minutes).
4- Switch the RPM knob to the GEL position.
5- Record the maximum deflection of the dial before the Gel
breaks, as the Gel strength in lb/100 ft2. Ib/100 ft2 x 5.077 =
Gel strength in dynes/cm2).

8. Gel Strength Jarjis Muhammad
Discussion:
Q1/ Are there any errors in this lab experiment?
Ans/
1- Human errors like fill the cup with mud more than position limits.
2- Quality of calibration fluid, to prevent this error we should get a best
quality of calibration fluid.
3- (Impure water) to prevent it we must get pure fresh water
Q2/ What are the points that increase gel strength for an oil base
drilling fluid?
Ans/ there are several points that will cause the high gel strength in the
mud system as follows. Drilling Operation Using Drill Mud • Over
treatment with organic gelling material • Build up of fine solid particles in
the mud.
Q3/ What the difference between Critical and Static gel strength?
Ans/ •Static Gel Strength - rigidity in the matrix which resists forces placed on it •
Critical Gel Strength - the gel strength which the hydrostatic column (when
accompanied by volume reduction)
Q4/ Why gel strength important in the drilling process?
Ans/ 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.

9. Gel Strength Jarjis Muhammad
Q5/ Why do we need to record the 3-rpm reading after 30
minutes?
Ans/ The reason is that the 30 minute-reading will tell us whether the mud will
significantly from the gel during extensive static periods like tripping out BHA or
not. If the mud has high gel strength, it will create a high pump pressure in order to
break circulation after the mud is static for a long time. Furthermore, increasing in a
trend of 30-minute gel strength indicates a buildup of an ultra-fine solid. Therefore,
the mud must be treated by adding chemicals or diluting it with fresh base fluid.
Q6/ What is the difference between Gel strength and Yield Point?
Ans/ Gel strength and yield point are both measures of the attractive forces in a fluid
system. The intial gel strength measures the static attractive forces, while the yield
point measures the dynamic attractive forces.
Q7/ What is the affect of mud density on gel strength?
Ans/ Gel strength is generally higher for lower density mud. The mud samples failed
at temperature of 250 F.
Q8/ How can gel strength affect mud loss?
Ans/ High gel strength can cause mud losses on connections, trips.

10. Gel Strength Jarjis Muhammad
References:
1. ASME Shale Shaker Committee.: “Drilling Fluid
Process, 2005.
2. Priston L. Moore: “Drilling Practices,” PennWell
Publishing Company Tulsa, 1988