The properties of drilling fluids that are often tested according to API regulations include: density, funnel viscosity, plastic viscosity, dynamic shear force, static shear force, API fluid loss, HTHP fluid loss, Ph value, alkalinity, sand content, and solid phase content , bentonite content, and various ion concentrations in the filtrate. Now, the commonly used performance test indicators of drilling fluids are introduced in detail.

1. PH value of drilling fluid

The pH value of the drilling fluid is used to indicate the acidity and alkalinity of the drilling fluid filtrate;

2. Drilling fluid density

The density of drilling fluid refers to the mass of drilling fluid per unit volume, usually g/cm3;

3. The sand content of drilling fluid

The sand content of the drilling fluid refers to the percentage of sand particles with a particle size larger than 74 μm that cannot pass through the 200-mesh screen in the drilling fluid in the total volume of the drilling fluid;

4. Solid phase content of drilling fluid

The solid phase content of the drilling fluid is usually expressed as the percentage of the volume of all solid phases in the drilling fluid to the total volume of the drilling fluid;

5. Rheology of drilling fluids

The rheology of drilling fluid refers to the characteristics of drilling fluid flow and deformation. Parameters: plastic viscosity, dynamic shear force, funnel viscosity, apparent viscosity and static shear force and other important rheological parameters of drilling fluid;

6. Wall-building properties of drilling fluids

During the drilling process, when the drill bit drills through the permeable formation, since the liquid column pressure of the drilling fluid is generally greater than the formation pore pressure, under the action of the pressure difference, the liquid of the drilling fluid will seep into the formation. Fluid loss of drilling fluid. At the same time of layer filtration of the fluid, the solid particles in the drilling fluid will adhere and deposit on the well wall to form a layer of mud cake.