复杂流体边界油藏注水井井底压力响应特征研究

STUDY ON CHARACTERISTICS OF INJECTION WELL BOTTOM-HOLE PRESSURE RESPONSE IN BOUNDARY RESERVOIR WITH COMPLEX FLUIDS

受储层非均质性的影响,在油田注水开发过程中,注入水会产生"舌进"、"指进"现象,使地下油水分布关系复杂化。目前利用常规解析解方法研究该类情形下的油藏渗流问题比较困难。为此,借助边界元理论在求解复杂外边界油藏渗流领域的优势。从渗流力学基本理论出发,采用Lord Kelvin点源解、贝塞尔函数积分和泊松叠加公式等方法求解出非均质油藏直井渗流的边界元基本解;沿井筒积分获得非均质油藏直井井底压力响应边界元解数学模型;通过理论计算得到了无因次压力和压力导数与无因次时间双对数理论图版;并详细分析了多种情形下井底压力动态的影响因素。此研究对油田注水开发具有一定的指导意义。

By the impact of reservoir heterogeneity, during the field water injection, injected water will have a 'tongued advance'、'fingering' phenomenon,which will complicate the relationship between the distribution of underground oil and water. Currently, using conventional analytical solution method to study reservoir seepage problem in such cases is somewhat difficult. With this advantages of boundary element theory in solving the complex reservoir seepage of outer boundary area, starting from the basic theory of fluid mechanics in porous medium; adopting methods of Lord Kelvin point source solution, Bessel function integral and Poisson superposition formula and so on solve boundary element fundamental solution of vertical well seepage in heterogeneous reservoirs. Integrating along the shaft,the mathematical model of the boundary element solution of vertical well bottom-hole pressure response was obtained in heterogeneous reservoirs; by theoretical calculation,the double log theory chart of the dimensionless pressure, pressure derivative and the dimensionless time was gotten. At the same time, the factors of affecting bottom pressure dynamic were analyzed in detail in various circumstances. This study has certain guiding significance to waterflood development.