OPTIMUM MUD WINDOW TO PROVIDE WELLBORE STABILITY AND REDUCE NON PRODUCTIVE TIME WHILE DRILLING IN MISHRIF FORMATION, SOUTH OF IRAQ

Abstract

Summary: This work deals with generating an integrated wellbore stability analysis for Mishrif Formation in South of Iraq area, using the Mechanical Earth Model (MEM). The start was calculating the overburden stress using the density logs, estimating the Pore pressure by using sonic log applying the Eaton method, after that the results have been calibrated using the real pressure data recorded in the well. Fracture pressure is then estimated from the overburden gradient and the pore pressure gradient has been calibrated by the complete losses events in Mishrif Formation and the use of hydraulic fracturing data. The poroelastic strain model is then used to estimate the magnitude of minimum and maximum horizontal stresses. Mohr-Colum Criterion was used to determine the failure conditions of the wellbore walls.