油藏大孔道模糊识别及定量计算方法研究

Research on fuzzy recognition and quantitative calculating method of large pore in reservoir

海上砂岩油藏在长期注水开发过程中,因高强度注水冲刷导致储层形成优势通道,致使注入水在注采井间低效甚至无效循环,严重影响水驱开发效果。为了解决注入水沿高渗优势通道突进难题,准确识别大孔道发育状况和大孔道参数计算成为一个技术关键。所以本文运用模糊综合评判法,优选5种静态指标和7种动态指标对储层大孔道进行定性判断;同时在流体渗流理论基础上,推导并建立大孔道渗透率、孔喉尺寸及大孔道体积的数学计算模型。实例应用结果表明文中模型的计算结果贴近生产实际,并且为封堵大孔道的调剖调驱工艺参数优化提供有效的数据支撑。

Loose sandstone reservoir is easy to form the large pore path during the development, influence the effect of water flooding development. Effective identification large pore path and accurate calculation of channel parameters, can guide the management of the large pore path, and improve the development effect. After analyse the response characteristics of large pore path and the characteristics of reservoir parameters, select 5 static indexes and 7 dynamic indexes, using the analytic hierarchy process(AHP)to determine the weight of each index, finally the large pore path identification was established based on fuzzy evaluation theory model. At the same time, on the basis of making full use of static and dynamic data of oilfield, the mathematical model of calculating invalid water quantity in producing oil well is deduced by using seepage theory. Then, according to Carman-Kozeny formula and non-darcy flow formula of high speed, the formulas for calculating permeability, radius and pore volume of large pore path between injection and production wells are derived. The method is proved to be accurate, reliable and applicable by the results of the identification of large pore path and the calculation of specific parameters in the actual well group.