Geomechanical Modeling for Determining Safe Mud Window and Evaluating Wellbore Wall Stability Using Numerical Simulation: A Case Study
محورهای موضوعی : Mechanics of Solids
Mohammed Rasmi Raheem Alomairi
1
,
Mojtaba Rahimi
2
1 - Department of Petroleum Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
2 - Department of Petroleum Engineering, Khomeinishahr Branch, Islamic Azad University, Khomeinishahr/Isfahan, Iran
کلید واژه: Wellbore stability, Azimuth, Mohr-Coulomb failure criterion, Mogi-Coulomb failure criterion, Safe mud window. ,
چکیده مقاله :
Mohr-Coulomb and Mogi-Coulomb failure criteria and caliper logs were utilized to determine the safe mud window. The results demonstrated that the formations located at the north wing of the studied oil field are more stable than the other zones. Among the investigated zones, Zone 5 is the most stable and Zone 6 is the least stable zone in terms of shear stability. Zones 1 and 2 in the south wing and Zones 3 and 4 in the middle wing of the oil field are also highly unstable. The Mohr-Coulomb failure criterion is more competent in predicting the stability of the wells compared to the Mogi-Coulomb failure criterion. The main reason for instability in the wells of this oil field is the selection of non-proper mud weight (usually far smaller than optimal mud weight) while drilling. The least mud window is in the middle zone in Well 3, and the safe mud window is about 15 Mpa in other parts of the field. In Zones 6 and 7 of the field, the safe mud window is 22.95 and 32.92 MPa, respectively. A 40-degree azimuth is the safe drilling route to decrease the instability of wells during drilling operations in this field.
Mohr-Coulomb and Mogi-Coulomb failure criteria and caliper logs were utilized to determine the safe mud window. The results demonstrated that the formations located at the north wing of the studied oil field are more stable than the other zones. Among the investigated zones, Zone 5 is the most stable and Zone 6 is the least stable zone in terms of shear stability. Zones 1 and 2 in the south wing and Zones 3 and 4 in the middle wing of the oil field are also highly unstable. The Mohr-Coulomb failure criterion is more competent in predicting the stability of the wells compared to the Mogi-Coulomb failure criterion. The main reason for instability in the wells of this oil field is the selection of non-proper mud weight (usually far smaller than optimal mud weight) while drilling. The least mud window is in the middle zone in Well 3, and the safe mud window is about 15 Mpa in other parts of the field. In Zones 6 and 7 of the field, the safe mud window is 22.95 and 32.92 MPa, respectively. A 40-degree azimuth is the safe drilling route to decrease the instability of wells during drilling operations in this field.
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