Husam Alkinani and Abo Taleb Al-Hameedi
Missouri University of Science and Technology, USA
Posters & Accepted Abstracts: J Pet Environ Biotechnol
Wells drilled in Rumaila field are highly susceptible to lost circulation problems when drilling through Hartha formation. This paper presents a comprehensive statistical work and sensitivity analysis models of the lost circulation events for more than 75 wells. Moreover, this study will demonstrate an integrated analysis regarding the most significant drilling parameters, which have pivotal impact on the lost circulation to provide the greatest chance of mitigating or avoiding lost circulation in Hartha zone. Lost circulation events are extracted from daily drilling reports, final reports, and technical reports. Key drilling parameters are analyzed using statistical software to understand the relationship between the mud losses and various drilling parameters such as MW, ECD, Yp, ROP, SPM, RPM, WOB, flow rate, and bit nozzles. The sensitivity analysis is conducted to examine the impact of each parameter in all models using Frontline Solver software. In addition, variance inflation factor method is used to test for the multicollinearity phenomena in each model to maximize the accuracy and to obtain a solid mathematical model. The volume loss model is conducted to predict lost circulation in Hartha formation. As a proactive action, this model can be used to estimate the volume loss model prior drilling Hartha zone. Observations that have been made from the volume loss model are MW, ECD, and Yp have a significant impact on lost circulation respectively; however, SPM, RPM, and ROP have a minor effect on the volume loss model. Equivalent circulation density model is obtained to estimate ECD in Hartha zone, and from this model can be deduced that MW, ROP, and Q have a significant impact on ECD respectively; nevertheless, RPM and Yp have a minor impact on the ECD. Rate of penetration model is made to estimate ROP in Hatha formation. It is concluded that WOB, SPM, and RPM have a significant impact on the ROP respectively, but MW, ECD, and Yp have a minor influence on the ROP. In addition, engineering solutions are developed to give a clear image regarding lost circulation, and it will provide a unique statistical study and coherent sensitivity analysis of all factors which have an essential or a small impact on this issue.