1. THE EFFECTS OF GEL STRENGHT
ON THE OVERALL PERFOMANCE
OF DRILLING FLUID
SEMINAR PRESENTATION
BY
ALADETAN FELIX.I

2. CONTENTS
• CONTENTS
• INTRODUCTION
• WHAT IS GEL STRENGHT
• TYPES OF GEL STRENGHT AND HOW IT IS MEASURED
• FACTORS THAT AFFECT GEL STRENGHT IN WBM
AND OBM
• EFFECTS OF EXCESSIVE AND WEAK GEL STRENGHT
• TREATMENTS AND IMPORTANCE OF GEL STRENGHT
• CONCLUSION

3. INTRODUCTION
A proper drilling fluid is designed based on the requirement of the
application In which it will be used. Its properties directly relates to its
function.
The desired properties must be understood and routinely evaluated through
Testing.
A series of measurement are taken to test for this properties so as to obtain
Crucial information about the performance of the drilling fluid.
One of such information is the cutting carrying capacity of the fluid which
Defines the Gel Strength of the fluid.
The Gel Strength is one property that involves both measurement and
Further evaluation to fully understand and derive maximum benefit from
Its use.
It’s a rheological measurement taken with a viscometer after varying
Lengths Of static condition.

4. WHAT IS GEL STRENGHT?
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 most important drilling fluid
properties because it demonstrates the ability of the drilling mud
to suspend drill solid and weighting material when circulation is
ceased.
Its important in all drilling fluid industries as many fluids are
thixotropic (time dependent). As the fluid remain static or un
agitated especially during connections and operational down
time, it begins to gel. This gelling aid the suspension of cuttings
while fluid motion is stopped.
A drilling fluid must be capable of effective cutting transport
under dynamic conditions and appropriate but not excessive
suspension under static condition.

5. HOW CAN WE MEASURE GEL 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 10sgel reading approximate the true yield stress for most systems.

7. TYPES OF GEL STRENGHT AND HOW IT IS MEASURED
• Depending on the time it takes to gel, we have three types of
gel strength namely:
• The high flat gel
• The progressive and
• The low flat gel (most desirable)
Depending on the range between 10s and 10mins gel reading.
The range or difference is significantly high for both the high
and progressive gel, and it indicate rheological troubles for the
mud .but there is no real difference for that of the low flat gel.
The magnitude of gelation with time is a key factor in mud and it
should not be too high to suspend cuttings and weighted
materials.

9. FACTORS THAT AFFECT GEL STRENGHT
WATER BASED MUD
• Bacteria
• Drill solid
• Salt
• Chemical contamination as
lime, gypsum, cement, and
anhydrite
• Acid gases as Carbon
Dioxide, and Hydrogen
Sulphide
OIL BASED MUD
• Over treatment with organic
gelling material
• • Build up of fine solid
particles in the mud

10. EFFECTS OF EXCESSIVE AND WEAK GEL STRENGHT
AND TREATMENT
EXCESSIVE GEL STRENGHT
• Swabbing
• Surging
• Difficulty in getting logging tools to
the bottom
• Retaining entrapped gas, cuttings
and sand while drilling
• Increase in gel strength is always
equals increase in YP
• Loss of fluids down hole
• Formation matrix can be damage
while attempting to free stuck pipe.
• Increased ROP and high pumping
pressure that may break formation
and result n loss circulation issues
WEAK GEL STRENGHT
• Inadequate cutting suspension
ability
• Build up of cutting bed with the
bore path tending to stuck pipe
• Poor hole cleaning
• Contamination problems
• Barite sag

11. TREATMENT AND IMPORTANCE OF GEL STRENGHT
1.Dilution: this is the simplest method for lowering solid concentration.
Keep total mud volume as small as practical and dump as much mud as
possible before each dilution.
2.Mechanical separation: screening and applied g force settling are the two
most commonly used.
3.Chemical – Mechanical separation: the use of both chemical and screening
devices and or g- force (chemical flocculation and dewatering)
IMPORTANCE
The major advantage of a good gel strength is its cuttings suspension ability
which will provide a good hole cleaning process.

12. CONCLUSION
It is obvious from the above information that a good low flat gel
strength is as important as a well formulated drilling fluid. They
say solid is the mud engineer's greatest enemy, looking at the
varieties of problems associated with high solids concentration,
like a wise teacher once said ‘it is better to avoid high solid
concentration than to know all the treatment techniques’.
Thank You