Measuring method of bentonite content in drilling fluid for complex deep well

To solve the greater deviation of bentonite content measuring result in drilling fluid during complex deep well field operation, the experiment methods for improving measuring accuracy of bentonite content in drilling fluid for complex deep wells was investigated, based on analyzing the affecting factors on bentonite content measuring accuracy, The effect of salt content, pH value and additives on measuring accuracy of bentonite content was analyzed and then the bentonite content measuring method of national standard GB/T16783-1997 was improved. Results showed that the salinity, pH value, additive types and usage all affect the measuring result. With salinity increases, the measuring result is getting less than the actual value, and with the increase of pH value and additive absorbing methyleneblue, the measuring result is getting more than the actual value. According to improved measuring method, the addition of 2.5 N sulfuric acid is 0.5 mL, and that of 5% H2O2 is 15%, while the pH value of testing liquid is 9.0. The improved bentonite content measuring method has high accuracy and good parallelism.