渤海Y油田基于泰尔指数的纵向吸水差异性研究

Vertical water absorption difference based on Theil index in Bohai Y oilfield

由于渤海Y油田采用多层合注合采方式开发,层间矛盾突出,吸水差异性大。为定量评价吸水差异性,并找出差异性主要来源,应用泰尔指数研究纵向吸水差异,并对泰尔指数进行分解,研究储层间和储层内部吸水差异性对总差异的贡献率。结果表明,随着注水开发的深入,Y油田泰尔指数逐渐变大,注水差异越来越突出;以KH计算的泰尔指数更能反映吸水差异性,而以小层吸水厚度计算的泰尔指数则无法完全反映这种差异;Y油田吸水差异主要来自各类储层内部的差异,主要为Ⅰ类储层的吸水差异,下步分层调配需重点降低Ⅰ类储层吸水差异性。

Developed by multi-layer combined injection and production,the interlayer contradiction is prominent and the water absorption difference is large in Bohai Y oilfield.In order to evaluate the water absorption difference and find out the main source of the difference,the vertical water absorption difference is studied by using the Theil index,which is decomposed to study the contribution of the water absorption difference between and within the reservoir to the total difference.The results show that with the deepening of water injection development,the Theil index of Y oilfield becomes larger,and the water injection difference becomes more prominent.The Theil index calculated by KH can better reflect the difference of water absorption,but the Theil index calculated by the thickness of water injection in a small layer cannot fully reflect this difference.The water absorption difference of Y oilfield mainly comes from the internal difference of various reservoirs,mainly the water absorption difference of class I reservoir.In the next step of layered allocation,it is necessary to focus on reducing the water absorption difference of class I reservoir.