基于分形理论的硫沉积气藏渗流模型研究

Research on Percolation Model of Sulfur Sedimentary Gas Reservoir Based on Fractal Theory

在高酸性天然气的开采过程中,随着地层中热力学条件的改变和孔隙流道中水动力学条件的变化,气藏中所含元素硫易在地层中尤其是井筒附近发生硫沉积.表现为距离丼筒越近的区域硫沉积越严重,地层渗透率和孔隙度也越低.采用二区复合模型描述高酸性气藏中存在这样两个性质不同的流动区域,同时考虑到已有大量研究证实沉积物在其积聚过程中会出现分形结构,因此利用分形理论建立了近丼筒附近变物性的非均质模型,对模型进行求解,并探讨和分析各参数对压力动态的影响,新模型能够更加准确的描述近丼筒附近硫沉积对地层污染和伤害研究成果可为该类气藏开发提供技术支持.

During the development of high-acid gas reservoir,with the change of thermodynamic conditions in the formation and the change of hydrodynamic conditions in the pore channels,the elemental sulfur contained in the gas reservoir is prone to sulfur deposition in the formation,especially near the wellbore.The performance is that the closer area to the wellbore,more serious the sulfur deposition,the lower formation permeability and porosity.In this paper,a two zone composite model is used to describe the existence of such two different flow areas in a high acid gas reservoir.At the same time,considering that a large number of studies have confirmed that sediments will appear fractal structures during their accumulation,the fractal theory is used to establish near-wellbore.The model is solved,and the influences of parameters on pressure behavior and productivity are discussed.The new model can more accurately describe the pollution and damage of the formation near the wellbore by sulfur deposits.The research results can provide technical support for gas reservoir development of this type.