三重介质复合气藏水平井不稳定产量递减动态分析

Research on rate decline analysis for horizontal well in triple-porosity composite reservoir

随着能源需求增长,碳酸盐岩勘探开发受到了广泛重视。在试井分析中,碳酸盐岩储层通常被视为三重介质(裂缝、基质、孔洞),但目前针对该类气藏的非稳态产能研究还相对较少。其次,很多气藏实际开发过程中由于酸化、压裂或气藏本身的特点,会使得气藏近井区和远井区的储层物性存在差异形成复合气藏。建立了将储层考虑为三重介质的复合气藏水平井的不稳定渗流模型,利用Laplace变换、正交变换等方法获取了模型的无因次解析解。在此基础上,分析了相关参数对三重介质复合气藏水平井不稳定产量递减动态的影响。此项研究丰富了复合气藏不稳定渗流的相关理论,对更好地认识该类气藏渗流规律和生产动态特征有一定的指导意义。

With the increase of energy demand,the exploration and development of carbonate reservoirs have attracted more attention from various countries.Carbonate reservoir is often regarded as the triple-porosity reservoirs（matrix pores,fractures and caves）in well test model.However,the current research on rate decline analysis of this type of reservoir is relatively few.Secondly,there is a difference in the properties of near wellbore area and the area far from the wellbore because of the formation acidizing,fracturing or the characteristics of the reservoir itself.This kind of reservoir is called composite gas reservoir.Therefore,an unsteady flow model for horizontal well with consideration of triple-porosity medium in composite gas reservoir is established.Using complex mathematical methods for instance：Laplace transformation,orthogonal transformation,the analytic solution of the proposed model is obtained.We also analyzed the effects of relevant parameters on rate decline type curve of horizontal wells in triple-porosity composite gas reservoir.This work enriched the relevant theories of this area,and it has important guidance for better understanding the percolation flow and the production performance of this typical reservoir.