Humic Acids 

DRILLING FLUIDS

Humic acidsare organic carboxylic acids of complex molecular structure (aromatic and phenolic). The water solubility of lignite depends on ist humic acid content. Decarboxylation of humic acid groupds by hydrolysis in alkaline muds is a major source of carbonate and bicarbonate anions in water muds.

They can be used as a fluid loss additive in oil base and water base drilling fluids. Humic acids have three types of functions when used in drilling fluids. First of all, they reduce viscosity and gel strengths. Second, they function as thinners, deflocculants, dispersants and as rheological control agents. Third, they also act, as stated above, as fluid loss agents and emulsifiers. 

Especially potassium humates are used mainly as a kind of a shale inhibiting agent for freshwater drilling fluids and have a function of viscosity reducer and water-loss reducer.  


Specifications

HUMIN P 775 is a specially selected leonardite material which has been carefully reacted with potassium compounds. This reaction neutralizes the humic acids which are abundant in the raw material, converting them to water-soluble potassium humates. The finished product is a causticized powdered leonardite, readily soluble in low-pH muds, and is essentially sodium-free. It is an excellent emulsifier for oil-in water emulsions fluids and it provides filtration control in water-based drilling fluids.  

Application 
HUMIN P 775  is a versatile product which functions as a deflocculant and filtration control agent in fresh, brackish, sea and salt water muds. It is especially useful in inhibitive muds which utilize potassium or other compounds to inhibit clay activity in the drilling fluid and in the formations penetrated. Furthermore, it helps to reduce viscosity and gel strengths of any drilling fluid and it reduces the effects of contaminants on drilling fluid properties. 

It is possible to combine the product with inorganic salts, such as potassium chloride or potassium carbonate. Drilling fluid is thermostable up to 220o C. For such borehole fluid of application, doses of 7-8 weight percents of the product are used .

Advantages 

  • Readily soluble in low pH-muds
  • Does not add sodium or free hydroxyl (OH-) to the mud system to aggravate clay cleavage and swelling.
  • Deflocculates clay solids without strong dispersing action.
  • Reduces filtration, both API and HPHT.
  • Versatile. Functions in most water-base mud systems.
  • Acts as contributory source of potassium (K+) in inhibitive muds.
  • Stable at high temperatures. ?Serves as an emulsifier for oil.
  • Has excellent solubility in water-based drilling fluids.
  • Remains effective in the presence of contaminants.
  • Can be used in salty formations and salty make-up water.  

Recommended Treatment
1 to 6 (2,9 to 17,1 kg/m³) in fresh and brackish systems for deflocculation and filtration control. 3 to 10 ppb (8,6 to 28,5 kg/m³) in higher-salinity systems. Higher dosages may be used in high-temperature applications. 

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