An Approach to Safely Install Tie-Back Casing String in Workover Operations Having Existing Lower Completion by Utilization of V0 Stage Tool

Abstract The paper illustrates a novel approach for Tie-back casings installation in Workover operations scenario where lower part of the wellbore may have limitation due to pre-installed lower completion or a complex well profile. The conventional approach for Tie-back casing installation contains high risk or is inapplicable in Workover application with existing lower completions. Therefore, cementing technique for Tie-back casing using a V0 stage tool presents a fit to purpose solution to a unique problem in industry. Since the technique addresses a fundamental application of tie-back casing running therefore its utilization can have a worldwide impact in similar applications in petroleum industry. Development of presented approach is through the process of lesson learnt & continuous improvement. In conventional tie-back cementation, a barrier plug (float equipment / cement plug / bridge plug) is utilized as a base to circulate up cement behind tie-back casing. However, the conventional scenario changes for a workover well where lower completion is pre-installed and cement plug or bridge plug cannot be set due to the risk of clogging downhole completion tools. In such cases, V0 stage cementation approach for tie-back casing provides an optimum solution to minimize the risk of downhole completion tools damage and securely achieves the well objectives. The technical advantage lies in minimizing the risk of cement sinking into lower completion and minimizing the drill out debris generated & sunk in hole from landing collar in comparison to a permanent bridge plug or cement plug. In addition to the technical benefits, the overall job process is streamlined by removing additional trips for bridge plug or cement plug placement, equivalent to an average saving of a half day to two days of Rig time and associated cost.