The methylene blue capacity of drilling fluid is an indication of the amount of reactive clays (bentonite and/or drill solids) present as determined by the methylene blue test. The methylene blue capacity provides an estimate of the total cation exchange capacity of the drilling fluid solids. Methylene blue capacity and cation exchange capacity are not necessarily equivalent, the former normally being somewhat less than the actual cation exchange capacity.
Methylene blue solution is added to a sample of drilling fluid (which has been treated with hydrogen peroxide and acidified) until saturation is noted by formation of a dye "halo" around a drop of solids suspension placed on filter paper. Variations of the procedure used on the drilling fluid can be performed on drill solids and commercial bentonite to allow an estimate of the amount of each type of solid present in the fluid (see API RP 131 [4]).
Drilling fluids frequently contain substances in addition to reactive clays that absorb methylene blue.Pretreatment with hydrogen peroxide is intended to remove the effect of organic materials such as lignosulfonates, lignites, cellulosic polymers, polyacrylates, etc.
Methylene blue solution is added to a sample of drilling fluid (which has been treated with hydrogen peroxide and acidified) until saturation is noted by formation of a dye "halo" around a drop of solids suspension placed on filter paper. Variations of the procedure used on the drilling fluid can be performed on drill solids and commercial bentonite to allow an estimate of the amount of each type of solid present in the fluid (see API RP 131 [4]).
Reagents:
- METHYLENE BLUE SOLUTION 1ML-0.01 ME; 16 OZ
- HYDROGEN PEROXIDE; 3%; 8 OZ
- DEIONIZED WATER; 8 OZ
- SULFURIC ACID 5 N; 8 OZ (UN # 2796)
No comments:
Post a Comment