Through this work, the following conclusions can be made: The Tresca criterion accompanied by the Mohr Coulomb, Mogi Coulomb, and Modified Lade criteria was used to estimate minimum overbalance pressure and mud density in vertical and deviated wellbore.
The mud density range has as constraints: pore pressure (minimum limit) and fracture pressure (maximum limit).
On the contrary, if one substitutes the maximum and minimum principle stress into Eq. 15 when the collapse occurs, then the critical drilling mud density which maintains the wellbore stability, known as collapse pressure, can be obtained.
The safe operation time can be increased by increasing mud amount or reducing mud density appropriately.
The drilling mud density significantly affects the deformation of and the mud loss from a wellbore during drilling.
(j) The procedures for well plugging, the depths and the types of plugs, and minimum mud weight.
The critical (minimum) mud pressures, predicted by the current elastoplastic analysis based on different wellbore instability criteria, are compared with the value corresponding to the elastic theory.
Genetic algorithm (GA) was applied as a main optimization engine that employs proportional feedback controller to obtain the minimum mud pressure required (MMPR).
(k) A description of the equipment, materials, and procedures for well plugging, including plug depths, plug types, and minimum mud weight.
This indicates that cutting transport in the annulus enhances as velocity, mud density, viscosity and rotation of drill pipe increase.
