A Pioneer Step in Restoring Well Integrity of Extreme Sour Well Through End to End Workover Optimization Utilizing Lean Methodologies

Abstract

Abstract Yibal Khuff (YK) is a highly sour oil field located in the North of Sultanate of Oman. During Production phase, pressure builds up the annulus behind production tubing resulted in integrity failures, where wells workover required. This paper demonstrates how the operator successfully reduced the planned intervention time by 60 % and restore wells back to healthy production. The paper will also explain how engineering enhancements and innovative Lean methodologies were used for efficiency optimization. Lean Project (LP), an innovative continuous improvement-based approach; was re-structured to address end to end (E2E) workover challenges. The Project stakeholders management consisted of utilizing Suppliers, Inputs Process, Outputs and Customers (SIPOC) which included identification of main stakeholders, assessment of impact and Voice of Customers (VOC). Value Stream Mapping (VSM) exercise was done for the workover and resulted in list of waste and opportunities to optimize the process. VSM allowed for visualizing the end-to-end process and optimize Process Cycle Efficiency (PCE). Root Cause Analysis (RCA) was conducted using the "5 Whys" method. Moreover, countermeasures were assessed and designed to be deployed. After piloting the suggested solutions with required controls in place, and because of LP countermeasures, a 60% reduction in planned operation time and 54% cost saving have been observed. This was achieved by eliminating the un-planned change in well sequence which eliminated 62.4 hours of operational downtime through developing fit per purpose sequence procedure. Combining Casing scraper and polish mill in one run saved 98.64 hours compared to planned phase duration. Optimization of operational steps reduced the Gap to Potential (GtP) time by 60% and eliminated Invisible Lost Time (ILT). In addition, the process was reflected in a Standard Operating Procedure (SOP) to be used and replicated across YK field. Finally, the SOPs that were developed on this project supported the local cluster in minimizing oil deferment by reducing the duration of hoist workovers and by raising the cluster's integrity compliance to a near-perfect record. This paper will give a brief about the application of Lean thinking methodology in a large Omani operator and how the LP tool can help identify and solve day to day problems within well interventions. The LP technique was used for the first time to optimize high sour high risk workover processes. Tools including, stakeholder engagements, root cause analysis and value stream mapping will be explained in this paper in more detail.