Water Production Problem in Gas Reservoirs: Concepts, Challenges, and Practical Solutions

Abstract

Gas resources play a key role in nowadays energy supply and provide 24% of the diverse energy portfolio. Water encroachment is one of the main trapping mechanisms in gas reservoirs. It decreases recovery by reduction of reservoir life, limits productivity and efficiency of wells, and elevates safety risks in gas production. The lack of a comprehensive study about water production problems is the primary motivation for this study. Contrary to the serious concern over the standalone investigation of an actual water production case study, less concern is put to deal with the problem comprehensively through an investigation of all potential sources and mechanisms, required methods, and available techniques. This study presents the potential sources of the problem, methods to identify it, and approaches to address it. Firstly, possible sources are described. Secondly, the diagnostic techniques are expressed. Then, practical solutions used in actual cases to overcome problems are elaborated. The solutions include both well- and reservoir-oriented approaches. Finally, all proper strategies are summarized to tackle the water problems in gas fields. The current study comprehensively presents the available methods for water control problems in parallel with conceptual and qualitative comparison. The finding of this study can be very constructive for better understanding of water sources, available diagnostic tools, and solutions for controlling water production in gas reservoirs and, consequently, taking the best decision in real case studies before attempting many water shut-off approaches.

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“…Altogether, the hydrocarbon production may degrade further. − The water blockage also happens in the bulk of the reservoir, especially in tight gas reservoirs that have smaller grains and, thus, pore throats that lead to higher capillary pressure and higher irreducible water saturations and, so, affect the effective permeability of the gas phase . In the gas reservoir, if the water sources are huge and the water permeability is high, the water invades the gas zone leading to a large amount of gas being trapped with significant decreases in its recovery factor. , The condensate blockage may also be considered a skin effect near the wellbore, which leads to a higher pressure drop and deviation from optimum operation in the IPR-TPR (Inflow Performance Relationship–Tubing Performance Relationship) curve . As a result, valuable hydrocarbons are lost, and the condensate formation can effectively decrease the economic productivity of the reservoir.…”

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