基于DFN的页岩气储层裂缝建模研究

Shale gas reservoir fracture modeling research base on discrete fracture network model

针对页岩气储层天然裂缝发育的特征,建立采用DFN离散裂缝网络模型的裂缝性储层建模方法和思路。以页岩I区块为例,首先建立页岩气藏三维构造模型,采用序贯高斯模拟方法,建立页岩气藏基质属性模型,奠定了裂缝建模的基础;接着在地震属性体约束下,以裂缝密度、长度、倾角及方位角等数据建立裂缝密度分布模型;最后以裂缝密度模型为控制条件,采用离散裂缝网络技术建立裂缝网络模型及裂缝孔隙度、渗透率等属性模型。通过生产动态分析,该模型满足气藏数值模拟精度要求,能比较真实的描述页岩气储层天然裂缝的几何特征和分布形态。

For the natural fracture-bearing shale gas reservoirs, an approach of discrete fracture network（DFN）model of fracture reservoir is used. For the shale gas of I block as an example, firstly, the three-dimensional structure model is established. Using sequential gauss random modeling established the matrix attribute model, laying a foundation for fracture and discrete crack model of coarsening. Secondly, according to the fracture density, length, az-imuth from well logging interpretation, the distribution of fracture density model is set up,un-der the constrain of the seismic fracture prediction attribute.Finally, fracture density distri-bution models as constraint conditions, the use of discrete fracture network（DFN）technology,establish the shale gas reservoir in this end block discrete fracture network model and the model of the fracture porosity, permeability and other properties. Through validation of the model analysis, the model can objectively fairly reflect the geometrical characteristics of the natural fracture and CBM reservoir distribution pattern for the blocks in shale reservoir nu-merical simulation provides a geological foundation and basis.