Optimization of shale gas development parameters based on embedded discrete fracture model
The Weiyuan shale gas area is an important battlefield of national shale gas demonstration area,and it has already achieved large-scale benefit development.With the continuous increase of its commercial exploitation scale,however,horizontal well spacing decreases,and fracturing stages and fracturing fluid consumption increase,leading to a complicated multi-well fracture network.As a result,the production exhibits the characteristics of rapid production decline and serious interference between wells.In order to achieve a high yield and stable production of single well and an effective large-scale development of shale gas,it is in urgent need to optimize the development parameters of Weiyuan shale gas area.In this paper,the complex fracture network in Weiyuan shale gas area is characterized precisely by using the embedded discrete fracture model,based on the geological characteristics in different regions of this area.In addition,the development parameters such as well spacing,fracture spacing,conductivity and horizontal section length of horizontal well in four types of typical zones of shale gas reservoir in this area are optimized.And the following research results are obtained.First,the embedded discrete fracture model can characterize fractures accurately and is more suitable for the optimization of parameters related to fractures in the process of shale gas reservoir development.Second,the optimal well spacing is positively correlated with the porosity and permeability of the block.The greater the fracture half-length,the larger the optimal well spacing.Third,reducing the fracture spacing can increase the total length of the hydraulic fractures,thereby effectively increasing the shale gas production.Therefore,in the process of development,the fracture spacing shall be reduced as much as possible while small interference between the fractures is ensured.Fourth,under the same geological conditions,the fractures with different half lengths show basically the same impact trend on the gas production rate after the spacing between the shale gas wells is optimized.Fifth,the longer the horizontal section of horizontal well,the higher the shale gas production rate.In conclusion,the research results can provide a technical basis for the scientific preparation of a shale gas development scheme and fracturing scheme,and are of great guidance and reference significance for improving shale gas recovery efficiency.
Sichaun BasinWeiyuanShale gasOptimization of development parametersEmbedded discrete fracture modelNumerical simulation
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