Water-based muds

16-13

EZ-MUD Formulation

The following table provides guidelines for formulatingEZ-MUD systems.

• Products are listed in order of addition.• Contingency products are denoted by an asterisk

(*); they can be used with the primary products toobtain properties needed for specific situations.

Additive Function lb/bbl (kg/m )Typical concentrations,

3

Caustic soda/ Alkalinity source (pH 9-10) 0.1-1.5 (0.3-4)Caustic potash

Soda ash Calcium remover As needed

AQUAGEL Viscosifier 5-17.5 (14-50.0)Suspension agent

EZ-MUD Shale stabilizer 0.5-3 (1.4-9)EZ-MUD DP 0.2-1 (0.6-3)

CELLEX Fluid loss control agent 0.2-3.5 (0.6-10.0)

PAC Fluid loss control agent 0.2-3.5 (0.6-10.0)

BAROID Weighting agent As needed

BARAZAN PLUS Viscosifier 0.1-1.0 (0.3-3)

*DEXTRID Fluid loss control agent As needed

*BARO-TROL Fluid loss control agent As needed

*FILTER-CHEK Fluid loss control agent As needed

*ALDACIDE G Biocide As needed

*THERMA-THIN Deflocculant 0.2-3.0 (0.6-9)Table 16-6: EZ-MUD product guidelines. This table lists products and provides typicalproduct concentrations for formulating a EZ-MUD system.

Baroid fluids handbook

Revised August 1, 1997 16-14

Note: The base fluid can be fresh water, sea water, orbrine. Add salt (as required) to increase salinity.

Formulation guidelines

Treat out hardness with soda ash and caustic sodabeing careful not to increase the pH above 10.

Prehydrate AQUAGEL and AQUAGEL GOLDSEAL before using.

Add EZ-MUD slowly through the hopper. A special shearing device may be helpful.

Note: A viscosity hump will occur when the EZ-MUD is added. With shear, the viscosity shoulddecrease as the system becomes deflocculated.

Note: To obtain the same polymer concentration, use 1/3 as much EZ-MUD DP as liquid EZ-MUD.

Breakover guidelines

Most low-solids, nondispersed systems with a low-to-moderate pH range can be converted to an EZ-MUDsystem. To convert, follow these steps.

1. Check the mud's pH, hardness, MBT volume, andlow-gravity solids content and adjust the mud, ifnecessary.Note: The higher the solids and MBT levels, thelonger and more severe the breakover hump will be.

2. Add the recommended concentration of EZ-MUD.

Caution: Extreme flocculation of the mud mayoccur, resulting in water separation. DO NOT adddeflocculants at this time. The condition willsubside after the EZ-MUD has been sheared.

Water-based muds

16-15

3. Add CELLEX, PAC-R, or PAC-L, as required, forfiltration control.Note: The system may become thin after adding afiltration control agent.

4. Add BAROID to increase mud weight, as required.

Maintenance guidelines

Maintain approximately 0.5 lb/bbl (1.5 kg/m ) of3

excess EZ-MUD in the filtrate as determined usingthe PHPA test.

The pH should not exceed 10. Maintain a total hardness of less than 200 mg/L for

maximum EZ-MUD stability. Presolubilize all caustic materials and add them

slowly to the active system. This will prevent thesystem from getting pH hot spots.

Use citric acid treatments to lower the pH, whennecessary. Other weak acids can be used to lowerpH elevated by cement contamination.

If ammonia odor is detected while drilling cement,assume EZ-MUD content is zero.