Wells in Basra\u27s oil fields are highly susceptible to lost circulation problems when drilling through the Dammam, Hartha, and Shuaiba formations. Drilling engineers are challenged to select the optimum value for key drilling parameters such as ECD, Yp, MW, WOB, ROP, and RPM to mitigate mud losses in these formations. Many of these drilling parameters are inter-related and the overall impact of changing key parameters require extensive drilling experience and study. A multi-regression analysis was performed on mud loss event data for more than 300 wells drilled in Basra\u27s oil fields. From this analysis, a model was developed to predict the total mud losses. Mud loss was found to be significantly affected by MW, ECD, and ROP. Models for ECD and ROP were also developed from the multi-regression analysis.
In the same vein, proactive approaches are made prior entering the Dammam, Hartha, and Shuiaba formations to prevent or mitigate the occurrence of the lost circulation. Key drilling parameters are estimated to use during drilling through these formations. In case preventive measures didn\u27t work, corrective actions are determined for each type of the mud losses to provide effective remedies, minimize NPT, and reduce cost.
This dissertation will contribute toward a better understanding of how the different factors could affect the lost circulation which is believed to have a significant impact on the mitigation mud losses. Therefore, optimized preventive and corrective solutions will be designed for combating lost circulation --Abstract, page iv
