Mud Testing

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

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

Sheet: Chart1

600.0

600.0

300.0

300.0

60.0

60.0

35.0

35.0

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 COLORpH < 8.3

PHENOLPHTHALEIN - PINK COLORpH > 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 = 0ALKALINITY IS ALL HCO3-Pf = MfALKALINITY IS ALL OH- 2 X Pf > MfALKALINITY IS MIXTURE OF CO3= & OH-2 X Pf = MfALKALINITY IS ALL CO3= 2 X Pf < MfALKALINITY IS MIXTURE OF CO3= & HCO3-

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= -------> Ag2CrO4AT 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)(Fw)

GARRETT GAS TRAIN - GGTMEASURES CARBONATES IN WATER MUDSMEASURES SULFIDES IN WATER MUDSMEASURES SULFIDES IN OIL MUDSMEASURES CARBONATES IN BARITE

GARRETT GAS TRAIN - GGT

PERMEABILITY PLUGGING TESTERHIGH PRESSURE/HIGH TEMPERATURE FILTRATIONSYNTHETIC FILTERING MEDIUMMEASURES SPURT LOSS AND FILTER CAKE DEVELOPMENTMINIMIZES SETTLING WHICH CAN AFFECT FILTRATION RATE

PERMEABILITY PLUGGING TESTER

STATIC AGING TESTMEASURES STABILITY OF MUD AT HIGH TEMPERATURESTEST SIMULATES STATIC WELLBORE CONDITIONSDETERMINES THERMAL STABILITY OF WATER AND OIL MUDSCAPABILITY OF 20,000 PSI AND 500 F

ELECTRICAL STABILITYUSED TO MEASURE RELATIVE STABILITY IN OIL/SYNTHETIC MUDSUSED IN CONJUNCTION WITH HPHT TO DETERMINE EMULSION STABILITYAFFECTED BY CONDUCTIVE SOLIDSOR VOLUME OF WATER

ELECTRICAL STABILITY