摘要
低渗透油藏孔喉结构复杂、孔喉半径细小,流体在低渗透油藏中的流动表现出明显的非线性渗流特征,同时存在一定的启动压力梯度。分析毛细管中边界层厚度变化规律,基于低渗透油藏流体边界层理论和毛细管模型,建立低渗透油藏非线性渗流新模型。通过低渗透岩心的流动实验验证了新模型的正确性,总结了单井径向非线性渗流模式;基于渗流区域的差异性特征,提出了低渗透油藏差异化开发对策。理论分析表明:基于边界层理论的低渗透油藏非线性渗流模型能够准确地描述低渗透油藏的渗流特征,低渗透油藏的渗流区域划分为易流区、缓流区与滞留区,不同类型低渗透油藏,易流区边界与缓流区边界之间的差距是不同的,提高采收率的技术方向不同。针对一般低渗透油藏,可以通过井网适配的方法建立有效驱替压力梯度,促使注采井间缓流区的边界对接,提高油藏波及系数;特低渗透油藏可通过储层改造等措施,促使缓流区转化为易流区;致密油藏通过优化合理井距,减少死油区,提高油藏储量动用程度。
The pore throat structure is complex and the pore throat radius is small in low permeability reservoirs.The fluid flow in the low permeability reservoir shows obvious non-linear percolation characteristics,and there is a certain start-up pressure gradient.The thickness variation characteristics of boundary layer within the capillary is analyzed.Based on the boundary-layer theory of fluid and capillary model of the low permeability reservoir,a new non-linear percolation model in the low-permeability reservoir is established.The new model is verified by the flow experiments of the low-permeability cores,and the radial non-linear percolation model of a single well is summarized.Based on the differences of different percolation regions,the differential development strategies of the low permeability reservoirs are determined.The theoretical analysis shows that the non-linear percolation model of the low permeability reservoir based on boundary-layer theory can accurately describe the flow characteristics of fluid in the low permeability reservoir.The percolation area of the low permeability reservoir can be divided into fast flow area,slowly flow area and detention area.The difference between the boundary of fast flow zone and that of slowly flow zone is different,and the technical approach of enhancing oil recovery is different for different types of low permeability reservoirs.For the general low permeability reservoirs,the effective displacement pressure gradient can be established by well-pattern matching,which promotes the boundary docking of slowly flow zones between injection and production wells and improves sweep coefficient of reservoirs.The slowly flow area can be transformed into fast flow area through reservoir stimulation and other measures in the ultra-low permeability reservoirs.By optimizing well spacing,dead oil areas can be reduced and the producing degree of reservoir reserves can be increased in the tight reservoirs.
作者
张世明
ZHANG Shiming(Exploration and Development Research Institute,Shengli Oilfield Company,SINOPEC,Dongying City,Shandong Province,257015,China)
出处
《油气地质与采收率》
CAS
CSCD
北大核心
2019年第6期100-106,共7页
Petroleum Geology and Recovery Efficiency
基金
国家科技重大专项“渤海湾盆地济阳坳陷致密油开发示范工程”（2017ZX05072）
关键词
低渗透油藏
边界层
非线性渗流
毛细管模型
径向渗流模式
low permeability reservoir
boundary-layer
nonlinear percolation
capillary model
radial percolation model
