Field test for determining emulsifier concentrations in drilling fluids

A method comprising:

• obtaining or generating a calibration curve correlating absorbance to an emulsifier concentration from reference samples, wherein the reference samples comprise:
• different concentrations of a reference emulsifier;
• a dye solution;
• and
• a hydrocarbon liquid;
• preparing a test sample comprising the steps of:
• obtaining a volume of a treatment fluid;
• adding a volume of the dye solution to the volume of the treatment fluid, wherein an oil-soluble emulsifier and dye complex is formed when the concentration of an emulsifier in the treatment fluid is greater than 0 pounds per barrel;
• separating a supernatant from solids in the treatment fluid, wherein the supernatant comprises the oil-soluble emulsifier and dye complex, if formed;
• and
• removing a volume of the separated supernatant, wherein the volume of the supernatant is the test sample;
• measuring an absorbance of the test sample using an instrument;
• and
• determining a concentration of the emulsifier in the test sample by comparing the measured absorbance to the calibration curve.

A method comprising:

• 1) forming a volume of drilling fluid at a mud plant, wherein the drilling fluid comprises a hydrocarbon liquid and an emulsifier;
• 2) preparing a test sample comprising the steps of:
• (i) obtaining a volume of the drilling fluid after the drilling fluid is formed at the mud plant;
• (ii) adding a volume of a dye solution to the volume of drilling fluid, wherein an oil-soluble emulsifier and dye complex is formed;
• (iii) separating a supernatant from solids in the drilling fluid, wherein the supernatant comprises the oil-soluble emulsifier and dye complex;
• and
• (iv) removing a volume of the separated supernatant, wherein the supernatant is the test sample;
• and
• 3) determining a concentration of the emulsifier in the drilling fluid by comparing the test sample against a reference sample, wherein the reference sample comprises:
• (i) a known concentration of a reference emulsifier;
• (ii) the dye solution;
• and
• (iii) a hydrocarbon liquid.

A method comprising:

• 1) introducing a drilling fluid into a subterranean formation for forming a wellbore, wherein the drilling fluid comprises a hydrocarbon liquid and an initial concentration of the emulsifier;
• 2) preparing a test sample comprising the steps of:
• (i) obtaining a volume of the drilling fluid during or after formation of the wellbore;
• (ii) adding a volume of a dye solution to the volume of drilling fluid, wherein an oil-soluble emulsifier and dye complex is formed when a residual concentration of the emulsifier in the drilling fluid is greater than 0 pounds per barrel;
• (iii) separating a supernatant from solids in the drilling fluid, wherein the supernatant comprises the oil-soluble emulsifier and dye complex, if formed;
• and
• (iv) removing a volume of the separated supernatant, wherein the supernatant is the test sample;
• and
• 3) determining the residual concentration of the emulsifier in the drilling fluid by comparing the test sample against a reference sample, wherein the reference sample comprises:
• (i) a known concentration of a reference emulsifier;
• (ii) the dye solution;
• and
• (iii) a hydrocarbon liquid.