Productivity Comparison of Different Completion & Stimulation Strategies with Underbalanced Coiled Tubing Drilling in Gas Carbonate Reservoirs

Abstract Gas condensate reservoirs often require special completion and stimulation techniques to maximize productivity. Workovers performed due to well integrity issues often lead to formation damage which can severely impact the production potential from these wells. Some of the most commonly used well completion techniques are conventionally stimulated vertical wells, Multi-Stage Fracturing (MSF) with ball drop systems or plug and perf systems. More recently, these completion systems have been challenged by Underbalanced Coiled Tubing Drilling (UBCTD), which has proven to yield high. This paper aims to compare the post-completion production performance achieved with these completion techniques with special emphasis on UBCTD while factoring in reservoir characteristics that contribute to such results. Furthermore, to thoroughly assess the productivity index associated with each well type, an extensive review was conducted on the advantages and limitations of UBCTD, MSF wells, and conventionally stimulated vertical wells. The review focused on the various factors that influence productivity, such as relative comparison of reservoir properties, wellbore stability, drilling fluid selection, and completion techniques. This paper introduces a novel integrated approach to evaluate the PI of gas wells drilled using UBCTD technology, MSF wells, and conventionally stimulated vertical wells. Specialized plots were developed which helped in comparative assessment of the different completion types and also understand the differences. The proposed method combines the analysis of normalized field data, numerical simulation and a comprehensive review, offering a more reliable and accurate assessment of well productivity and the reasoning behind exhibited results. Furthermore, the paper highlights the importance of considering various factors, such as drilling fluid selection, and completion techniques, in optimizing the PI of gas wells. This study provides valuable insights for reservoir engineers, drilling engineers, and decision-makers in selecting the optimal well configuration and drilling technology to maximize hydrocarbon production.