基于均衡驱替理念的水驱油藏注采设计方法

Production Design Methods for Water Flooding Reservoir Based on the Concept of Balanced Displacement

制定科学合理的注采方案是水驱油藏的一项核心任务,需要充分考虑油藏储层和开发的动静态非均质特征,影响因素多,量化决策难。为此,从油藏开发基本理论出发,以减小驱替不均衡为目的,推导建立了非均质油藏在定液量和定压差两种不同生产方式下的注采参数设计公式,分析了储层动、静态参数对注采参数设计的影响规律,形成了非均质油藏均衡注采设计新方法。利用算例对比分析了传统方法和新方法的差异,最后开展了矿场应用分析。研究明确了油水井注采设计受井距、孔隙度、渗透率、当前含水饱和度等因素的影响规律,指出高含水期油藏注采设计对于当前含水饱和度的敏感性显著提升;同等条件下,均衡注采设计新方法要优于传统方法。矿场应用实践表明,采用新方法设计的注采方案,目标井组日增油0.9 t,含水下降0.3%,日无效注水减少37.5 m^(3),井组吨油耗水量和运行成本也大大降低,有效支撑了油藏经济高效开发。

Designing a scientific and reasonable production plan is a core task for water flooding oil reservoirs.The decision need to fully consider the dynamic and static heterogeneity characteristics of the reservoir geology and development.There are many influencing factors,which make quantitative decisions difficult.Therefore,starting from the basic theory of reservoir engineering,aiming at reducing imbalanced displacement,the injection and production parameter design formulas for heterogeneous reservoirs under two different control methods,constant liquid rate and constant bottom hole pressure,were derived.The influence rules of dynamic and static reservoir parameters on injection production design were analyzed.A new method of balanced injection and production design for heterogeneous reservoirs was formed.The difference between the traditional method and the new method was compared and analyzed with an example,and finally the application analysis of an oil field was carried out.The study clarified that the injection-production design of oil-water wells was affected by well spacing,porosity,permeability,current water saturation and other factors,and pointed out that the sensitivity of the high-water-cut oil reservoir injection-production design to the current water saturation was significantly improved.Under the same conditions,the new method was better than the traditional method.The field application practice shows that using the injection-production scheme designed by the new method,the oil rate increases 0.9 t/d for the target well group.The water cut is reduced by 0.3%,the daily ineffective water injection is reduced by 37.5 m^(3),and the water consumption per ton of oil and operating cost are also greatly reduced,which effectively supports the economic and efficient development of oil reservoirs.