EQUIPMENT
• Corrosion rings pre-weight 4.5” (AISI 4140)
• Drill string PROCEDURE
• Insert a corrosion ring into the tool joint closest to the drill bit.
• Insert rings at halfway and at the top end of the drill string.
• To keep in situ at least 40 hrs and max. of 10 days.
• Recover the test pieces, dry them off with a cloth.
• Notice the original weight and serial number.
• For each corrosion ring, record : 1) Phase and depth of the ring.
2) Seria number and original weight.
3) Date and time of installation in the string 4) Date and time of recovery
5) Mud type, pH, Temperature in/out, flow rate.
6) Description of any treatment with corrosion inhibitors.
Send the test pieces to and the report data to: Eni-Agip/Corm RESULT
• Speed corrosion
lbs/ft3/year mm/year Interpretation
<1 <0.6 Low
1 - 2 0.6 - 1.2 Moderate
2 - 5 1.2 - 3.1 High
>5 > 3.1 Severe
Equipment Required:
• Electrical stability meter, 0-200 volt range, optimum operating frequency of 330-350 hertz at 1500 volts, 61 microamps of current at emulsion break. Electrode probe with space of 1.59mm (0.061 in.)
• 0-150oC (32-220oF) thermometer
• Heating cup
• Glass or plastic beaker Procedure:
1) Place a sample of the filtrated fluid from the screen of the marsh funnel into the heating cup.
2) Heat sample at 50oC (120oF).
3) Put the sample into a plastic or glass container.
4) Position the electrode probe into the fluid sample.
5) Stir the sample with electrode probe for 15-30secs.
6) Be sure that the electrode probe is completely covered by the sample. It must not touch the bottom or sides of the container.
7) Push test button and start from zero by rotating the PO tentsionmeter clockwise with increments of 100-200 v/sec. (Most models start up automatically.)
8) Record the ES value displayed on the readout device (which is lit at the passage of current).
9) Record the reading and reset potentiometer.
10) Clean the electrode probe with a tissue paper.
11) Repeat test and evaluate accuracy. Re-stir the sample for 30secs and repeat from step 4 to step 9 .
Results:
Electrical stability = 2 (reading of potentiometer)(27).
(27)
Some emulsion testers, i.e. Bariod’s testers, provide the value of electrical stability directionally.
• Half litre glass jar with lid.
• 5cc syringe.
• 5cc graduated pipette.
• Magnetic stirrer with 38mm stirring bar (1.5in) . Reagents:
• Xilene/Hysopropanole mixture: 50/50.
• Distilled water.
• Phenolphthalein.
• Sulphuric acid: 0.1 regular (N/10) . Procedure:
1) Add 100cc xilene/hysopropanole mixture to half litre jar.
2) Add 2cc fluid with the syringe.
3) Swirl the mixture until it is homogenous.
4) Add 200cc distilled water.
5) Add 15 drops of phenolphthalein.
6) Slowly titrate with 0.1 N sulphuric acid, while stirring rapidly with magnetic stirrer.
7) Titrate until red colour just disappears for 1min.
8) Let the sample stand for 5mins, if no red colour re-appears, the end point has been reached.
9) If colour reappears, titrate until it disappears again. Repeat steps 6,7,8.
10) If a third titration is necessary, call the total value of acid the end point, even if the colour re-appears a fourth time .
Results:
Fluid Alkalinity:
Pom = cc 0.1N sulphuric acid/cc fluid sample.
Pom = cc 0.1N sulphuric acid/2.
Excess Lime:
lbs/bbl = 1.3 Pom.
kg/m3 = 3.7 Pom.
• Half litre glass jar with lid.
• 5cc syringe.
• 5cc graduated pipette.
• 10cc graduated pipette.
• Magnetic stirrer with 38mm stirring bar (1.5in) . Reagents:
• Xilene/Hysopropanole mixture, 50/50.
• Distilled water.
• Phenolphthalein.
• Sulphuric acid: 0.1 regular (N/10).
• Potassium chromate indicator.
• 0.282N silver nitrate . Procedure:
1) Lead the alkaline test as indicated in the previous form.
2) Be sure acqueous solution pH is less than 7 by adding 1-2 drops of N/10 sulphuric acid.
3) Add 10 to 15 drops of potassium chromate indicator(28). 4) While stirring rapidly, slowly titrate with silver nitrate(29).
5) When the pink salmon colour stabilises for at least 1min, then the end point has been reached .
Results:
Fluid chloride (mg/l) = 1000 (cc AgNO3 * PM(30) Cl-)/cc fluid sample required.
Whole fluid chloride (mg/l) = 10000 (cc AgNO3 0.282N(31))/2.
(28) A further addition of potassium chromate may be required.
(29) Rapid stirring is required. It may be necessary, however that the stirring is stopped to allow separation of the two phases to occur.
(30) Pm Cl = PE Cl = 35.45.
(31) The normal 0.0282 N reagent is calculated as follows: 1cc AgNO3 equals 10g/l Cl.
• Half litre glass jar with lid;
• 5cc syringe
• 5cc graduated pipette
• 10cc graduated pipette
• Magnetic stirrer with 38mm stirring bar (1.5in ) Reagents:
• Xilene/Hysopropanole mixture, 50%/50%
• Distilled water
• 1N hydroxide sodium (NaOH) 1N
• Calcium indicator (Calver II)
• 0.1M EDTA(32 ) Procedure:
1) Add 100cc of 50/50 xilene/hysopropanol mixture.
2) Add 2cc of fluid with syringe.
3) Shake vigorously, until the mixture is homogeneous.
4) Add 200cc distilled water.
5) Add 3cc 1N NaOH.
6) Add 0.1 - 0.25gr calcium indicator (Calver II).
7) Shake vigorously for 2mins.
8) Let the sample stand to allow the separation of the two phases to occur. If a reddish colour appears in the aqueous phase, calcium is present.
9) Place the jar on the magnetic stirrer and drop in the stir bar.
10) Titrate with 0.1 M EDTA.
11) When the colour changes to blue-green, the end point has been reached.
12) Record the number of cc of 0.1M EDTA required . Results:
Fluid calcium (mg/l) = 1000 (cc EDTA * Normal EDTA PMCa++)/cc of fluid sample
Whole fluid calcium (mg/l) = 1000 (cc EDTA * 0.1 40/2cc
= 4000 (cc EDTA) 2cc
(32) This EDTA solution is ten times more concentrated than the solution required for water based fluids.
This coding system describes the Eni-Agip drilling fluid coding system currently in use and how the system can be used for further developments of drilling fluids.
A.1. CODE GROUPS
There are three groups in the system:
1 2 3
• The first grouping represents the base fluid, such as fresh water, sea water, diesel, etc. The base fluid must be included in the full code.
• The second grouping represents the base fluid system, such as lignosulfonate, gels, polymers, invert emulsion, etc. The base system again must be included.
• The third grouping describes the base system more precisely by providing further information: i.e. the water/oil ratio in an invert emulsion, the type of salt in a brine and underlining the specific treatment, such as addition of polymers, soltex, lignosulfonates. The third group is included only if relevant information is applicable.
If there is one or more special treatments, only the most significant of these will be included. For example, DS-IE 80 signifies a diesel base, invert emulsion drilling fluid, with a WO ratio of 80/20. If this drilling fluid is relaxed, the code would be DS-IE RF, as 'Relaxed Fluid' is to be considered a more significant characteristic than the W/O ratio.
1) The code for sea water fluid with prehydrated bentonite is:
SW GE
2) During drilling, if the fluid is treated with light additions of lignosulfonate, its code will be:
SW GE LS
3) Again during drilling, the addition of lignosulfonate will characterise the fluid further and the code will be:
SW LS
4) Finally, if lubricants are added, the code will be:
SW GE LU
B.1. FLUID CODE ABBREVIATIONS
1 2 3
Base Fluid Base System Specific Treatment
AR - Air AR - Air (- -) - Non Specific
FW - Fresh Water AT - Aerated CA - Calcium Carbonate
SW - Sea Water BR - Brine CB - Calcium Bromide
BW - Brine Water CL - Chromelignin CC - Calcium Chloride
DS - Diesel CT - Cationic Polymers CL - Chromelignin
LT - Low Toxicity Oil DE - Modified Tannins (Desco) KA - Potassium Acetate
EB - Ester DF - Drilling Fluid KB - Potassium Base (KOH)
OF - Poltolefine GE - Bentonite-Base KC - Potassium Chloride
UT - Olio Ultra LT GG - Guar Gum KF - Potassium Formiate
GL - Glycol-Base GL - Glycol-Base
GY - Gypsum-Base LI - Lime
HT - High Temperature LS - Lignosulfonate IE - Invert Emulsion LU - Lubricants K2 - Potassium Carbonate NC - Sodium Chloride KA - Potassium Acetate NB - Sodium Bromide KC - Potassium Chloride PA - Polyanionic Pol.(PAC) KF - Potassium Formiate PN - Na Polyacrylates
LI - Lime-Base PC - PHPA
LS - Lignosulfonate-Base PK - Agipak (K-CMC/PAC)
LW - Low-Solids PO - Generic Polymers (CMC)
MM - Mud-Misting RF - Relaxed Filtrate
MR - Morex-Base RM - Rheology Modifiers
OB - Oil Base RX - Ht Pol. Mixtures
PA - Polyanionic Pol.(PAC) SX - Soltex
PC - PHPA TA - Tannins
PK - Agipak (K-PAC, K-CMC) XC - XCD Polymer PO - Generic Polymers (CMC) VB - Viscosity Base
QU - Quebracho-Base ZB - Zinc Bromide
SF - Foam-Base
SS - Salt Saturated (NaCl) XC - XCD Polymer
NOTE: The oil/water ratio of a fluid with an oil numeric value, such as O/W = 70/30, will be expressed only by the first ratio, i.e. 70, omitting the later 30 ratio.
AF - Antifoam B - Bactericide C - Chelant CC - Diesel
CI - Low Toxicity Oil
E - Ester
F - Poltolefine FP - Olio Ultra LT FR - Filtrate Reducer
LC - Loss Circulation Material LU - Lubricant
P - Primary
pH - pH Control S - Secondary S - Solvent
SA - Suspension Agent SH - Shale Stabiliser SU - Surfactant TH - Thinner TR - Tracer
TS - Temperature Stability Agent V - Viscofier
W - Weighting Material