mud testing
TRANSCRIPT
Mud Testing Procedures and Equipment
MUD WEIGHT
MEASURES THE DENSITY OF THE MUD, THE WEIGHT OF A GIVEN VOLUME OF LIQUID.
LB/GAL
G/CM3 (LB/GAL)(0.1198)
LB/FT3 (LB/GAL)(7.48)
KG/M3 (LB/GAL)(120)
MEASURED WITH A MUD BALANCE OR PRESSURIZED MUD BALANCE
AERATED MUD WILL GIVE ERRONEOUS RESULTS
DE-AERATE MUD WITH A VACUUM PUMP OR USE PRESSURIZED MUD BALANCE
CALIBRATE MUD BALANCE WITH FRESHWATER
MUD WEIGHT RECORDED IN/OUT ON ROUTINE INTERVALS
TEMPERATURE/PRESSURE AFFECTS DENSITY IN OIL MUDS MORE THAN WATER MUDS
TEMPERATURE INCREASES VOLUME AND DENSITY IS LOWER
PRESSURE DECREASES VOLUME AND DENSITY IS HIGHER
Mud Balances
FUNNEL VISCOSITY
INDICATES RELATIVE THICKNESS OF A MUD
AFFECTED BY SIZE, SHAPE, NUMBER OF PARTICLES AND ATTRACTIVE FORCES OF THE MUD
MEASURED IN/OUT ON ROUTINE INTERVALS
IN VERSUS OUT VISCOSITY CAN INDICATE MUD CONDITION
LITTLE VARIATION OF IN/OUT VISCOSITY INDICATES ACCEPTABLE MUD CONDITION
LARGE VARIATION OF IN/OUT VISCOSITY INDICATES MUD NEEDS TREATMENT - MOST LIKELY
TREATMENT IS WATER DILUTION
BOTTOMS-UP VISCOSITY, IF EXCESSIVE, USUALLY REQUIRES CHEMICAL TREATMENT WITH SOME DILUTION
AERATED MUD CAN CAUSE HIGH VISCOSITY VALUES
TEMPERATURE AFFECTS OIL MUDS MUCH MORE THAN WATER MUDS
IN OIL MUDS, AS TEMPERATURE DECREASES, VISCOSITY INCREASES
IN OIL MUDS, THE TEMPERATURE OF THE SAMPLE MUST BE RECORDED
PLASTIC VISCOSITY (PV)
DETERMINED WITH A ROTATIONAL VISCOMETER
INDICATES SIZE, SHAPE AND NUMBER OF PARTICLES
PV,cP = 600 RPM READING - 300 RPM READING
TEMPERATURE AFFECTS PV IN OIL MUDS MORE THAN WATER MUDS
IN OIL MUDS, INCREASE IN TEMPERATURE CAUSES A DECREASE IN THE PV AND DECREASE IN TEMPERATURE CAUSES AN
INCREASE IN PV
HIGHER SOLIDS CONTENT OR REDUCTION IN PARTICLE SIZE WILL INCREASE THE PV
IN OIL MUDS, THE MORE EMULSIFIED WATER, THE HIGHER THE PV
R P M
0 200 400 600 800
P V
YIELD POINT (YP)
DETERMINED WITH ROTATIONAL VISCOMETER
INDICATES DEGREE OF ATTRACTIVE FORCES BETWEEN THE PARTICLES IN THE MUD
YP, LBS/100 FT 2 = 300 RPM READING - PV
CONTAMINANTS AND HIGH TEMPERATURES INCREASE YP. ADDITIONS OF LIME OR CAUSTIC WILL INCREASE YP IN CLAY-
WATER SYSTEMS
THINNERS WILL REDUCE THE YP MORE THAN WATER ADDITIONS WHEN CONTAMINANTS ARE PRESENT
EXCESSIVELY HIGH DRILL SOLIDS CONTENT REQUIRE WATER DILUTION BEFORE THINNERS BECOME EFFECTIVE
0 200 400 600 800
R P M
P V
YP
GEL STRENGTHS
MEASURED WITH A ROTATIONAL VISCOMETER
DETERMINE VISCOSITY AT LOW SHEAR RATE AND INDICATES THIXOTROPIC OR GEL FORMING PROPERTIES OF MUD.
MEASURED AT TWO DIFFERENT TIME INTERVALS (10 SECOND AND 10 MINUTE)
CLAYS AND XC POLYMER WILL PROVIDE THIXOTROPIC PROPERTIES
CONTAMINANTS AND HIGH TEMPERATURES CAUSE INCREASE IN GEL STRENGTHS. ADDITIONS OF LIME OR CAUSTIC WILL
INCREASE GEL STRENGTHS IN CLAY-WATER SYSTEMS
THINNERS WILL REDUCE THE GEL STRENGTHS MORE THAN WATER ADDITIONS WHEN CONTAMINANTS ARE PRESENT
EXCESSIVELY HIGH DRILL SOLIDS CONTENT REQUIRE WATER DILUTION BEFORE THINNERS BECOME EFFECTIVE
HIGH 10 MINUTE GEL STRENGTHS CAN RESULT FROM EITHER CARBONATE CONTAMINATION OR HIGH DRILL SOLIDS
CONTENT AND RESPOND TO DIFFERENT TREATMENTS
Rotational Viscometer
FILTRATION
LOW PRESSURE, LOW TEMPERATURE FLUID LOSS TEST
PERFORMED AT ROOM TEMPERATURE AND 100 PSI
DETERMINE FILTRATE VOLUME AND FILTER CAKE QUALITY
CONTAMINANTS CAUSE HIGH FLUID LOSS AND THICK FILTER CAKE
BENTONITE ADDITIONS REDUCE FILTER CAKE BY FORMING A MORE COMPRESSIBLE CAKE, DRILL SOLIDS CAUSE THICK
FILTER CAKES
FILTRATION
HIGH PRESSURE, HIGH TEMPERATURE FLUID LOSS (HPHT)
CAN BE RUN UP TO 500 °F AND 500 PSI DIFFERENTIAL
MORE REPRESENTATIVE OF BOTTOM HOLE CONDITIONS
DETERMINES FILTRATE VOLUME AND FILTER CAKE QUALITY
BENTONITE ADDITIONS REDUCE FILTER CAKE BY FORMING A MORE COMPRESSIBLE CAKE, DRILL SOLIDS CAUSE THICK
FILTER CAKES
FILTER MEDIUM EITHER FILTER PAPER, SYNTHETIC MADE DISKS OR ACTUAL DISKS CUT FROM CORE
UTILIZED FOR WATER AND OIL MUDS
USED TO DETERMINE TEMPERATURE STABILITY OF ALL MUD TYPES
SOLIDS SETTLING IN HPHT CAN LEAD TO HIGH FILTRATE
HPHT Filter Press
RETORT ANALYSIS
DETERMINES VOLUME OF SOLIDS, WATER AND OIL IN MUD.
CORRECTION MADE FOR SALT CONTENT SINCE SALT IS A DISSOLVED SOLID.
AERATED MUD WILL GIVE ERRONEOUS READINGS AND WILL RESULT IN HIGH SOLIDS CONTENT.
RETORT CHAMBER SHOULD BE CALIBRATED PERIODICALLY.
RETORT READINGS USED TO DETERMINE HIGH AND LOW GRAVITY SOLIDS CONTENT IN MUD SYSTEM.
GRADUATED CYLINDERS NORMALLY SUPPLIED WITH RETORT ARE INACCURATE.
Retort
SAND CONTENT
DETERMINE SAND CONTENT IN MUD SYSTEM
SAND IS CONSIDERED ANY PARTICLE LARGER THAN 200 MESH -
(74 MICRON)
SAND IS VERY ABRASIVE TO PUMP PARTS AND VALVES
METHYLENE BLUE TEST (MBT)
DETERMINES BENTONITE CONTENT OR EQUIVALENT IN MUD SYSTEM
MEASURE THE AMOUNT OF METHYLENE BLUE ADSORBED BY CLAYS
EXPRESSED AS LB/BBL BENTONITE EQUIVALENT
USED TO DETERMINE THE ACTUAL DRILL SOLIDS CONTENT
AS MUD WEIGHT INCREASES, THE MBT SHOULD BE REDUCED
CERTAIN MUD PRODUCTS CAN INTERFERE WITH RESULTS SUCH AS LIGNITES, LIGNOSULFONATES, CMC
INCREASE IN THE MBT CAN INDICATE REACTIVE CLAYS ARE BEING INCORPORATED IN THE MUD
MBT CAN BE DETERMINED ON CUTTINGS TO DETERMINE THEIR REACTIVITY
pH
RELATIVE ACIDITY OR ALKALINITY OF THE MUD
MEASURED WITH pH PAPER OR pH METER
pH PAPER CHANGE COLOR BASED ON pH OF THE MUD OR FILTRATE
pH PAPER AFFECTED BY CHLORIDES ABOVE 10,000 MG/L
pH METERS MORE RELIABLE THAN pH PAPER FOR MORE ACCURATE DETERMINATION AND ARE FIELD RELIABLE
INDICATORS PROVIDE pH MEASUREMENT BASED ON COLOR CHANGES OVER A BROAD RANGE
PHENOLPHTHALEIN - NO COLOR pH < 8.3
PHENOLPHTHALEIN - PINK COLOR pH > 8.3
THYMOLPHTAHLEIN - NO COLOR pH > 8.33 AND < 9.3
THYMOLPHTAHLEIN - LIGHT BLUE pH > 9.3 AND < 10.0
THYMOLPHTAHLEIN - DARK BLUE pH > 10.0
MOST MUDS REQUIRE AN ALKALINE OR BASIC CONDITION FOR PRODUCTS TO PERFORM PROPERLY
pH MEASUREMENTS BY ANY OF THE ABOVE DOES NOT INDICATE THE TOTAL ALKALINITY OF THE MUD SYSTEM
ALKALINITY (Contd.)
WITH THE Pf AND THE Mf, THE TYPE AND AMOUNT OF ALKALINITY CAN BE CALCULATED. THE FOLLOWING RELATIONSHIPS
CAN BE DETERMINED:
Pf = 0 ALKALINITY IS ALL HCO3
-
Pf = Mf ALKALINITY IS ALL OH-
2 X Pf > Mf ALKALINITY IS MIXTURE OF CO3= & OH-
2 X Pf = Mf ALKALINITY IS ALL CO3
=
2 X Pf < Mf ALKALINITY IS MIXTURE OF CO3= & HCO
3-
THE Pm IS THE AMOUNT OF ACID REQUIRED TO LOWER THE pH OF THE WHOLE MUD TO 8.3 AND IS A MEASURE OF THE TOTAL
SOLUBLE AND INSOLUBLE ALKALINITY IN THE MUD
THE EXCESS LIME IN A MUD CAN BE ESTIMATED BY MEASURING THE Pm AND THE Pf
EXCESS LIME, LB/BBL = 0.26(Pm -(Fw)(Pf))
IMBALANCE IN CARBONATE & BICARBONATE ALKALINITY CAN CAUSE VISCOSITY PROBLEMS THAT WILL NOT RESPOND TO
CHEMICAL THINNERS AND DOES NOT PROVIDE PROPER HYDROXYL ALKALINITY FOR LIGNOSULFONATES AND LIGNITES TO
FUNCTION PROPERLY
CHLORIDE TITRATIONS
MEASURES THE AMOUNT OF CHLORIDES IN THE MUD FILTRATE
TEST METHOD USES A PRECIPITATE METHOD TO MEASURE CHLORIDES
USED TO DETERMINE IF SALT OR SALTWATER HAS BEEN INTRODUCED INTO MUD SYSTEM
ENDPOINT OF REACTION IS WHEN COLOR CHANGES FROM YELLOW TO FIRST PERSISTENT ORANGE COLOR CHANGE. DO NOT
OVER TITRATE!
REACTION IS: AgNO3
+ Cl- ------> AgCl
2Ag+ + CrO4
= -------> Ag
2CrO
4
AT HIGH CONCENTRATIONS OF CHLORIDES, A CORRECTION FACTOR HAS TO BE CALCULATED AND SUBTRACTED FROM THE
SOLIDS CONTENT
HARDNESS
DETERMINES THE AMOUNT OF CALCIUM AND MAGNESIUM IN MUD FILTRATE
VERSENATE TEST MEASURES BOTH CALCIUM AND MAGNESIUM. CALVER TEST MEASURES CALCIUM ONLY
USED TO DETERMINE IF ANHYDRITE, CEMENT, CALCIUM CHLORIDE WATER FLOWS HAVE BEEN ENCOUNTERED
REACTION IS THE COMBINATION OF THE HARDNESS REACTING WITH THE INDICATOR AND TURNS FROM BLUE TO WINE
RED.
WHEN VERSENATE TITRATING SOLUTION (EDTA) IS ADDED THE HARDNESS COMBINES WITH THE EDTA AND THE COLOR
OF THE SOLUTION CHANGES BACK TO THE BLUE COLOR
THE CALVER TEST USES A STRONG BUFFER SOLUTION TO CAUSE THE MAGNESIUM TO DROP OUT OF SOLUTION AND THE
TITRATION WITH EDTA OCCURS ONLY WITH THE CALCIUM IN THE FILTRATE
THE DIFFERENCE BETWEEN THE VERSENATE TEST AND THE CALVER TEST WILL GIVE THE AMOUNT OF MAGNESIUM IN
SOLUTION
EXCESS GYP DETERMINED BY MEASURING THE CALCIUM OF THE WHOLE MUD AND CALCIUM OF THE FILTRATE:
EXCESS GYP, LB/BBL = (2.38)(Vm
) - (0.48)(Vf)(F
w)
GARRETT GAS TRAIN - GGT
• MEASURES CARBONATES IN WATER MUDS
• MEASURES SULFIDES IN WATER MUDS• MEASURES SULFIDES IN OIL MUDS• MEASURES CARBONATES IN BARITE
GARRETT GAS TRAIN - GGT
PERMEABILITY PLUGGING TESTER
• HIGH PRESSURE/HIGH TEMPERATURE FILTRATION
• SYNTHETIC FILTERING MEDIUM• MEASURES SPURT LOSS AND FILTER CAKE
DEVELOPMENT• MINIMIZES SETTLING WHICH CAN AFFECT
FILTRATION RATE
PERMEABILITY PLUGGING TESTER
STATIC AGING TEST
• MEASURES STABILITY OF MUD AT HIGH TEMPERATURES
• TEST SIMULATES STATIC WELLBORE CONDITIONS
• DETERMINES THERMAL STABILITY OF WATER AND OIL MUDS
• CAPABILITY OF 20,000 PSI AND 500 °F
ELECTRICAL STABILITY
• USED TO MEASURE RELATIVE STABILITY IN OIL/SYNTHETIC MUDS
• USED IN CONJUNCTION WITH HPHT TO DETERMINE EMULSION STABILITY
• AFFECTED BY CONDUCTIVE SOLIDS• OR VOLUME OF WATER
ELECTRICAL STABILITY
HPHT FILTRATION
• MEASURES FILTRATE IN WATER AND OIL/SYNTHETIC MUDS
• HIGH TEMPERATURE - 400 °F AND 500 PSI DIFFERENTIAL
• INDICATES STABILITY OF OIL MUDS• PROBLEMS WITH SETTLING AFFECTING
FILTRATION RATE
POTASSIUM DETERMINATION
• MEASURES POTASSIUM CONTENT OF KCL DRILLING FLUIDS
• USED TO DETERMINE POTASSIUM CHLORIDE PURITY
• DO NOT USE CHLORIDE CONTENT TO DETERMINE POTASSIUM CONTENT
• PROCEDURES FOR LOW AND HIGH CONCENTRATIONS OF POTASSIUM
PHPA DETERMINATION
• DETERMINES PHPA CONTENT OF A DRILLING FLUID
• MEASURED ON FILTRATE OF MUD
ALKALINITY/SALINITY ANALYSIS
• MEASURES ALKALINITY AND SALINITY CONTENT OF SYNTHETIC/OIL BASED MUDS
• DETERMINES WATER PHASE SALINITY• USED TO CORRECT SOLIDS CONTENT OF
SYNTHETIC/OIL MUDS• ASSESS PROPER ALKALINITY
FANN 70
• MEASURES RHEOLOGICAL PROPERTIES OF OIL AND WATER MUDS
• SIMULATES DOWNHOLE CONDITIONS OF TEMPERATURE AND PRESSURE
• MEASURE GEL STRENGTH AT TEMPERATURE AND PRESSURE
Test temperature > 150°F 150°F 250°F 300°F 375°FTest Pressure > 0 psi 1000 psi 6000 psi 12000 psi 16000 psi
Dial readings @:600 RPM 98 107 68 64 88300 RPM 55 58 38 38 48200 RPM 40 43 28 29 37100 RPM 27 28 19 18 256 RPM 7 8 5 5 53 RPM 6 7 4 4 4
Plastic Viscosity 43 49 30 26 40Yield Point 12 9 8 12 810 second gel 6 7 4 3 310 minutes gel 7 8 5 5 7
RHEOLGICAL PROPERTIES OF OIL MUD
PARTICLE SIZE DISTRIBUTION
• DETERMINES SIZE DISTRIBUTION OF SOLIDS
• USED FOR SOLIDS CONTROL EFFICIENCY• DETERMINES % BY VOLUME, NOT % BY
WEIGHT• DETERMINES SIZE OF BRIDGING SOLIDS
Particle Size DistributionMeasurement TableMicrotrac Analysis
Date: 23-Feb-98Project No.: S97001
Sample: S. Pass 78 C-21 MudSuspension Fluid: Water
Diameter CumulativeInterval less Diff
< micron % %0.97 1.74 1.741.38 5.94 4.201.94 11.77 5.832.75 21.60 9.833.89 30.20 8.605.50 38.47 8.277.78 46.78 8.31
11.00 55.62 8.8415.56 65.80 10.1822.00 74.67 8.8731.11 83.29 8.6244.00 91.32 8.0362.23 96.75 5.4388.00 99.43 2.68124.45 99.85 0.42176.00 100.00 0.15248.90 100.00 0.00352.00 100.00 0.00497.80 100.00 0.00704.00 100.00 0.00
Further Values
Diameter Cumulativemicrons less %
6 40.644 91.374 98.1
Diameter < 25 % = 3.2Diameter < 50 % = 9.0Diameter < 75 % = 22.4
Particle Size DistributionMicrotrac AnalysisS. Pass 78 C-21 Mud
Cumulative Volume Undersize Plot
0.00
25.00
50.00
75.00
100.00
0.10 1.00 10.00 100.00 1000.00Particle Size, micron
Solid
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% b
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Particle Size Histogram Plot
0.0
2.0
4.0
6.0
8.0
10.0
12.0
1.0 1.9 3.9 7.8 15.6 31.1 62.2 124.5 248.9 497.8Particle Size, micron
Solid
s Co
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% b
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