Flow Analysis: A Critical Step in Completion Design and Optimization. A Case Study of Multizone Completion Designs

Abstract Multizone completion systems are used worldwide as an efficient method to maximize reserves recovery. There are several assets in the deepwater Gulf of Mexico where this technology is the preferred option for optimizing drainage of multiple zones and/or reservoirs in the same well completion. However, the selection and design of these completions demand specialized evaluations of completion equipment, analysis of fluid properties and operating conditions, not only to maximize production but also to ensure the reliability of the completion system. The scope of this study covers completion design configurations and flow analysis for a well intersecting three zones (reservoirs), using completion data, fluid and reservoir properties to evaluate expected well production and completion reliability. Four completion design options were evaluated: one x dual zone and three x triple zone completions, each with a different flow configuration. The analysis adopted considers the entire completion system including fluid flow paths and actual dimensions of equipment and their position in relation to other equipment. The objective is to calculate the maximum production rate through a completion system based on erosion assessment, and also evaluate the pressure loss at defined production rates. Production scenario calculations were also performed at defined wellhead pressures. Flow analysis results show that the evaluated design options each offered unique capabilities based on a set of defined completion and production constraints. Each completion design exhibits different flow capacities with pressure loss variances. Results also identified sections within the completion systems where dimensions or other physical properties of equipment can be optimized to maximize the flow of produced fluid, and minimize the potential for erosion. This study identifies a methodology for completion design and optimization during field development planning and management. It provides valuable information and decision tools for reservoir (drawdown, flow rates, and fluid behavior conditions) production (flow rates and flow assurance) and completion engineering teams (optimized completion design, pressure, temperature and erosion parameters).