The following statement is correct ().The steeper the curve, the smaller the compressibility of the soil; The greater the compression coefficient, the greater the compressibility of the soil;The greater the compression index, the greater the compressibility of the soil;The greater the compression modulus, the greater the compressibility of the soil A: × √ √ × B: √ × √ × C: √ × × √ D: √ √ √ ×

If there is no solid in the fracturing fluid, and fluid viscosit is close to the viscosity of formation fluid, which will dominate the leakoff? A: Wall builiding. B: Fracturing fluid viscosity. C: Compressibility of formation fluids. D: Compressibility of fracturing fluid.

The main physical properties of the fluid are （ ） A: density B: compressibility C: viscosity D: velocity E: flow rate

At a certain temperature and pressure, the ratio of natural gas volume to ideal gas volume is defined as (). A: discrepancy index B: Compressibility factor C: Volume factor D: Elastic coefficient