Pressures are calculated at which the rock on the walls of the well will begin to collapse, due to insufficient (collapse) or too high (absorption, hydraulic fracturing) pressure of the drilling fluid.
Thus, at each point of the well trajectory, the values of pore pressure, pressures of destruction of the well wall, loss and fracturing are determined. RUSS is usually presented in graphical form, and pressure values are expressed in units of density (g/cm3).
This view is also called the safe drilling window or the combined gradients window. This is a necessary tool for every driller, allowing you to determine the optimal technological parameters, manage them during the drilling process and prevent geological complications during construction. The calculation of stability is especially relevant when drilling ultra-deep, horizontal and ERD wells, as well as in fields with complex tectonics and abnormal high pore pressure.
The calculation of the stability of the borehole wall serves as the basis for
- Optimization of trajectories and well designs
- Optimization of hydraulics and drilling fluids
- Rationale for choosing bits
- Calculation of cementing parameters
- Development of drilling risk maps
