油藏合理地层压力保持水平与含水率关系

Correlation between rational formation pressure and water cut

郭粉转 唐海 吕栋梁 曹峰

GUO Fenzhuan TANG Hai LV Dongliang CAO Feng

西南石油大学，四川成都　610500 中国石油天然气集团公司管材研究所，陕西西安　710065

Southwest Petroleum University, Chengdu 610500, China CNPC Pipe Institute, Xi’an 710065, China

地层压力是判断地层能量充足与否的一个重要标志。根据采油工艺基本原理和相渗关系推导出无因次采液指数和采液指数与含水率的关系式，在此基础上通过对油藏相对渗透率曲线的归一化处理，利用注采比原理，建立了不同采油速度下的合理地层压力与含水率以及注采比之间的关系，并给出油田应用实例。研究结果表明，无因次采液指数或采液指数取最小值时，合理地层压力保持水平会急剧降低。该方法对于分析中、低含水开发阶段注水工艺和采油速度具有一定指导意义。

Formation pressure is one of the important marks to determine the state of formation energy, and thus the rational formation pressure needs to be determined. On the basis of the fundamental principle of petroleum engineering and relative permeability, the relational expression showing the correlation between the nondimensional fluid productivity index and productivity index and the water cut are deduced. Then, according to the normalization processing of relative permeability curves from reservoirs and applying the principle of injection-production ratio, the paper presents the relationship between the rational pressure and water cut as well as injection-production under different oil production rate, and gives the practical application to oilfields. The result of study indicates that the rational formation pressure maintenance will decrease dramatically when the nondimensional fluid productivity index or productivity index takes the minimum value. This method has some scientific guidance and practical value for the analysis of the waterflood technology and production rate of low-to-moderate water development phase.