基于对称变换的水驱特征曲线趋势分析方法

Method of trend analysis of water flooding characteristic curve based on symmetry transformation

黄和钰 2 鞠斌山¹

中国地质大学（北京）能源学院，北京 100083 中国石油大学（北京）非常规天然气研究院，北京 102249）

School of Energy Resources, China University of Geosciences, Beijing 100083, China The Unconventional Natural Gas Institute, China University of Petroleum, Beijing 102249, China)

水驱特征曲线趋势分析是预测油田生产动态的重要方法。渗流特征方程作为油水相对渗透率比与含水饱和度关系曲线的表征形式，决定了相应的水驱特征曲线关系式。现有渗流特征方程局限于某一含水阶段的表征，人为割裂了渗流过程的整体性，导致相应的水驱特征曲线趋势分析无法充分利用早期生产资料，限制了预测油田生产动态的能力。为此，基于系统论的整体性思想重新审视了油水两相渗流特征，指出油水两相渗流过程呈近似的对称性，对称中心同时也是从油相渗流优势过渡到水相渗流优势的唯一拐点。根据油水两相渗流特征提出了新的渗流特征方程，完成了相应水驱特征曲线关系式的推导，并建立了新的水驱特征曲线趋势分析方法。新方法重视数据预处理，考虑油田系统结构变化，更具科学性。基于油水两相渗流的对称性特征，采取对称变换的新思路预测油田含水率上升趋势，充分利用了早期生产资料，大大提高了生产动态预测能力，对措施效果评价具有参考意义。

 Trend analysis of water flooding characteristic curve is an important method to predict production dynamic. Flow characteristic equation, which originates from the curve of relative permeability ratio(Kro/Krw) versus water saturation(Sw), determines the corresponding water flooding characteristic curve formula. Limited to certain water-cut stages, existing flow characteristic equations artificially split the integrity of the whole flow process. This results in the limitation of corresponding method of trend analysis of water flooding characteristic curve to predict production dynamic, failing to make full use of the early production data. Based on system theory, the characteristics of oil/water two-phase flow has been reviewed. The authors point out that oil/water two-phase flow in porous media seems to be symmetrical, the midpoint of water saturation may be the symmetry center, and it may be also the only inflection point through which water phase begin to have an advantage in flow capability. According to the characteristics of oil/water flow, a new flow characteristic equation is put forward, the corresponding water flooding characteristic curve formula is derived and a new method of trend analysis of water flooding characteristic curve is established. The new method is more scientific, because it includes data pre?-processing which takes oilfield structure change into account. On the basis of the symmetrical characteristics of oil/water two-phase flow, the new method adopts symmetry transformation and inversion, making full use of early production data, and remarkably improves the ability to predict production dynamic. And the new method is also valuable for treatment evaluation.

10.6056/dkyqt201701008