T field has very unconsolidated sand with high nonuniformity and high fines contents in H and I sands and require robust sand control, typically Internal gravel pack (IGP). Historically, around 90% wells have been completed with IGP completion and are producing sand free for the last 20-30 years. This paper describes on the first slim (3") open hole standalone screen (OHSAS) completion application and performance which can be utilized for replication in future infill wells.

Around 10% remaining wells have been completed with OHSAS completion across highly deviated wells in H and I sands in T field. The screens have been designed based on d10 sand particle size and sand retention test (SRT) and typically installed in 8 ½" open hole. The drill-in fluid (DIF) has been properly designed to create temporary filter cake across the wellbore and then it is designed to break by either lift-off pressure or by usage of mud cake breaker depending upon the type of DIF system.

The OHSAS wells are producing good with sand free production since last seven to fourteen years. The OHSAS performances for all wells in T field have been investigated. The investigation has provided suggestions for further improvement in future projects. Based on the investigation, OHSAS completions in T field has good OHSAS design and production performance, though further improvement can be done in its execution for future projects like monitoring total soluble clays using Methylene Blue Test (MBT) during drilling reservoir sections, maintaining its solubility more than 70% all throughout, use of proper mud cake breaker, etc. This paper explains details on the outcome of the investigation and recommendations, and data requirement to assess successful OHSAS completions with the help of tables and charts. The applicability of OHSAS has been re-studied in future infill wells and have been included in the next field development plans.

This paper presents on the OHSAS design, execution and performance, best practices, reviews and suggestions for further improvement in future infill wells, then its applicability and replication in future projects.

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