En este artículo, presentamos un modelo unificado de yacimiento de shale gas, que incorpora mecanismos de nano-flujo de transporte de gas real y geomecánica en el sistema de pizarra fracturada. Este modelo se usa para predecir la producción de gas de esquisto bajo diferentes depósitos escenarios e investigar qué factores controlan su tendencia a la baja. Los resultados y análisis presentados en el artículo nos brindan una mejor comprensión de la producción de gas y los mecanismos de disminución en un pozo de gas de esquisto con ciertas condiciones del embalse características. Un conocimiento más profundo sobre los efectos de los factores que controlan el comportamiento de la producción de gas puede ayúdenos a desarrollar modelos más confiables para pronosticar la tendencia al declive del gas de esquisto y la recuperación final. Este artículo también revela que algunas creencias comúnmente aceptadas pueden parecer razonables para inferir la tendencia de disminución de la producción, pero pueden no ser ciertas en sistema de reservorio en realidad.
What Factors Control Shale Gas Production and Production Decline Trend in Fractured Systems: A Comprehensive Analysis and Investigation
One of the biggest practical problems with the optimization of shale gas stimulation design is estimating post-fracture production rate, production decline, and ultimate recovery. Without a realistic prediction of the production decline trend resulting from a given completion and reservoir properties, it is impossible to evaluate the economic viability of producing natural gas from shale plays. Traditionally, decline curve analysis (DCA) is commonly used to predict gas production and its decline trend to determine the estimated ultimate recovery (EUR), but its analysis cannot be used to analyze what factors influence the production decline trend due to lack of underlying support of physics, which make it difficult to guide completion designs or optimize field development. In this article, we presented a unified shale gas reservoir model, which incorporates real gas transport, nano-flow mechanisms and geomechanics into fractured shale system. This model is used to predict shale gas production under different reservoir scenarios and investigate what factors control its decline trend. The results and analysis presented in the article provide us a better understanding of gas production and decline mechanisms in a shale gas well with certain conditions of the reservoir characteristics. More in-depth knowledge regarding the effects of factors controlling the behavior of the gas production can help us develop more reliable models to forecast shale gas decline trend and ultimate recovery. This article also reveals that some commonly hold beliefs may sound reasonable to infer production decline trend, but may not be true in a coupled reservoir system in reality.
