What Does Step-Down Test Mean?
A step-down test is conducted within an underground fracture to determine the cause of a drop in pressure near a wellbore. It is used to measure net pressure in a fracture within a trenchless construction excavation zone.
Trenchlesspedia Explains Step-Down Test
Along with in-situ and mini-fracture tests, step-down testing is part of the geological evaluation of a planned trenchless site. The objective of a step-down test is to measure the near-wellbore pressure through a series of fluid injections. The ultimate aim is to calculate the difference between the actual pressure and minimum in-situ stress inside a fracture.
The results of this net pressure calculation will indicate to trenchless operators the nature of the fracture and its inherent risks. A step-down test generally includes a series of five injections of fluids with known friction pressures. Trenchless experts may be able to determine the cause of the fracture from the test, whether due to perforation or tortuosity.