How do you test and measure the performance and rheology of drilling fluids for unconventional wells?

1 Fluid properties

The first step is to measure the basic fluid properties, such as density, viscosity, pH, salinity, and solids content. These properties affect the flow behavior, stability, and compatibility of the drilling fluid with the formation and the drilling equipment. You can use standard instruments, such as mud balance, viscometer, pH meter, conductivity meter, and retort kit, to measure these properties at the wellsite or in the laboratory. You should follow the recommended procedures and frequency of testing according to the industry standards and best practices.

2 Rheology models

The second step is to analyze the rheology of the drilling fluid, which is the study of how it deforms and flows under different shear rates and stresses. Rheology is important for determining the hydraulics, hole cleaning, pressure losses, and surge and swab effects of the drilling fluid. You can use different rheology models, such as Newtonian, Bingham plastic, power law, Herschel-Bulkley, and Casson, to describe the flow behavior of the drilling fluid. You can also use rheological parameters, such as yield point, plastic viscosity, apparent viscosity, and gel strength, to quantify the rheology of the drilling fluid. You can use a rheometer or a viscometer to measure these parameters at different temperatures and pressures.

3 Performance tests

The third step is to conduct performance tests on the drilling fluid to evaluate its ability to perform its intended functions and to meet the specific requirements of the unconventional well. These tests include filtration, lubricity, shale inhibition, and environmental tests. Instruments such as filter press, lubricity tester, shale roller oven, and toxicity analyzer can be used at the wellsite or in the laboratory. Procedures and standards of testing should be followed according to industry guidelines and best practices. The results of these tests indicate the sealing and bridging ability of the drilling fluid, its impact on torque and drag and bit life, its shale inhibition and dispersion ability, as well as its environmental friendliness and sustainability.

4 Optimization and monitoring

The final step is to optimize and monitor the performance and rheology of the drilling fluid for unconventional wells. Optimization involves adjusting the composition, concentration, and additives of the drilling fluid to achieve the desired properties and performance. Monitoring involves collecting and analyzing data from the wellsite and the laboratory to evaluate the effectiveness and efficiency of the drilling fluid. You can use various tools and techniques, such as mud logging, mud reports, hydraulics modeling, and real-time data transmission, to optimize and monitor the drilling fluid. You should follow the recommended practices and feedback loops of optimization and monitoring according to the industry standards and best practices.

5 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?