致密岩石渗透特性参数的测量解释方法

ON MEASURING AND INTERPRETATIVE METHOD OF PERMEABILITY AND POROSITY OF TIGHT ROCKS

  • 摘要: 确定储油气层岩石的渗透特性参数(例如,渗透率和孔隙度)是油气田勘探与开发中的一项基础工作,而对于低渗透致密岩石的渗透率,由于室内实验时流体流动速率很小,采用常规岩芯方法难以直接测量。根据实验室的岩芯分析装置和实验过程,通过数值求解描述流体在多孔介质中不稳定渗流的数学模型和自动拟合岩样上、下流压力随时间的变化,建立了识别岩芯渗透率和孔隙度的最优化模型,并给出了模型的数值解法。最后,通过理论验证和实测数据计算说明了方法的实用性和可靠性。

     

    Abstract: It is essential to determine the physical property parameters (for instance, permeability and porosity) of reservoir rock in exploring and developing oil or gas field. Because of the low flow rate, the normal core analysis is helpless to determine permeability of samples such as tight gas sands, limestones and shales. In this paper, an optimization model is established to calculate permeability and porosity of a core sample by means of auto-matching the pressure vs. time behavior observed at the end of the jacketed sample while a pore pressure pulse is applied to another. The numerical method of solving the optimization model and the mathematic model that describes fluid unsteady flow through porous medium are presented. The practicality and reliability of the measuring and interpretative method are verified in an example.

     

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