Horizontal wells in low to moderate permeability reservoirs are routinely fractured to obtain higher sustained production. A key element to consider for the success of a fracturing treatment is the optimum placement of multiple fractures in the lateral section. These treatments are known as multi-stage fracturing (MSF) and can generally be placed using open-hole multi-stage fracturing assembly (OHMS) or a more conventional perforate, stimulate, and plug (PSP) option in a cemented liner. This paper illustrates examples of production behavior from numerical modeling of gas wells drilled, completed, and stimulated in high pressure and high temperature environments, in low to moderate permeability reservoirs. Numerous comparisons of production performances modeled using numerical simulator for OHMS and PSP applications with varying reservoir and completion parameters are provided. Examples are depicted to show horizontal well performances and how candidates and completion assemblies are selected to obtain the best production rates. Various subsets of OHMS such as singleport ball drop system per stage, high velocity jetting through coiled tubing to create slots to effectively connect wellbore with the reservoir, and multiple cluster perforation system for limited treatment have all been used in the Saudi Arabian gas reservoirs. PSP method is also being considered and used. The paper refers to the impact of drilling azimuth, well cleanup, and application of polymer-free fluids on well performance. The paper also shows that drilling wells in the minimum stress direction in low permeability gas reservoirs, completing them with multistage fracturing assemblies, and conducting high-volume treatments contribute to sustained long-term productivity.

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