Analysis of Completion and Production Strategy for a Horizontal Well with Open Hole Gravel Pack. A Case of Study in Teak Field TSP, East Coast Trinidad

Abstract

One of the most critical issues in TSP fields is the unconsolidated character of its sands. Historically, most of the wells drilled in TSP fields, including vertical, deviated and horizontal wells, have been completed with cased hole gravel pack (CHGP). However, over the course of the years, these completions have been known to fail eventually, especially in the case of horizontal completions. Among the failure reasons are the complexity of such operations and the drawdown applied during production. During the last drilling campaign in 2014, a horizontal well was completed with open hole gravel pack (OHGP). In addition to the change of completion, the production strategy was also modified to delay the water breakthrough and reduce the drawdown. These changes have significantly contributed to increase the production of the asset and opened the opportunity to apply these changes in wells for future campaigns. The horizontal well, was drilled through unconsolidated sand (Pliocene), where continuous fluid losses were expected to be encountered. During the well project execution it was necessary to create a mitigation plan in order to minimize the risk of fluid loss (rate) circulation before running the lower completion. For this it was necessary to include an isolation valve to control the losses once the packer was confirmed to be set. Normal reservoir pressure, and available facilities, was key factor to decide to include a gas lifting system in the upper completion which was also designed to have the maximum ID as possible for future intervention jobs such as acid stimulation and logging operations. Finally the well was successfully completed in OHGP with no signs of bridging. Based on the results obtained a complete detailed analysis for the pre and post job will be exposed in this document. This paper outlines the different challenges faced, as well as to highlight the action plans, mitigations and lessons learned encountered during the planning, design, and execution of the completion phase. In addition, a review of the production history of similar completions and the production strategies followed will be discussed. Finally, the results of this well will be summarized and lessons learnt shared.