低渗透变形介质油藏渗流模型及计算方法研究

【作者】 王巧云；

【导师】 刘小华；

【作者基本信息】 西南石油大学 ， 应用数学， 2009， 硕士

【摘要】 随着石油资源的不断开发与利用,低渗透油田在开发中所占的比例越来越大。充分认识低渗透油田的渗流规律对低渗透油田的合理高效开发至关重要。大量的室内实验和矿场开发表明,低渗透油藏的渗流必须克服一定的启动压力梯度才能流动;其次,在低渗透油藏的开发中,由于原始渗透率和孔隙度很低,其油层的渗透率和孔隙度的相对变化幅度对油藏开发产生的影响仍然较大,所以需要考虑介质变形的影响。目前对于低渗透油藏的研究主要集中在单一因素对试井解释模型的影响,如单独考虑启动压力梯度或介质变形。本文在分析低渗透油藏渗流机理的基础上,综合考虑启动压力梯度和介质变形影响以及井筒储集和表皮效应的影响,建立了单重介质和双重介质低渗透油藏的试井解释模型。所得模型可归结为非线性抛物型方程的定解问题,综合比较现有的求解非线性抛物型方程的几种差分方法后,本文采用稳定性和收敛性都很好的预估校正法求解各个模型,并对预估校正法进行了精度分析。然后用Visual C#语言设计编写了求解模型的数值程序,运用数值程序求解了模型的数值解,并以双重介质模型为例,讨论了启动压力梯度、介质变形、井筒储集系数、表皮系数对压力响应的影响,分析了考虑和忽略启动压力梯度、考虑和忽略介质变形影响时压力的变化规律,还对启动压力梯度和渗透率模数的敏感性进行了对比分析,绘制了压力曲线图版。对低渗透油藏试井分析具有一定的理论应用价值。更多还原

【Abstract】 With the exploitation of the oil resource, the proportion of low permeability reservoirs has been under increasing. To fully recognize the percolation law of the low permeability reservoir is of great significance in developing the reservoir reasonably and effectively. It is showed by many laboratory experiments and field exploration that the percolation of low permeability reservoir must overcome the starting pressure gradient to be able to flow. Second, the primitive permeability and porosity are very low in the exploitation of low permeability reservoir, and the relative range of variation of the permeability and porosity still has great effect on the exploitation of the oil resource. Therefore it is necessary to consider the influence of the deformation of the media At present, the research of low permeability reservoir mainly concentrates on the influence of some single factor on the well test models, for example, only considering the starting pressure gradient or the deformation of the mediaBased on the analysis of the percolation regulation of low permeability reservoir, the well test models of the single media and the dual media in low permeability reservoirs are built in this paper, considering not only the influence of starting pressure gradient and deformation of the media, but also of the wellbore storage and skin effect. The models can be mathematically summarized into the definite solution of nonlinear parabolic equations. Comparing the difference algorithms for the nonlinear parabolic equations, this thesis adopts the predictor-corrector method, which has good stability and convergence to obtain the solution of the models. The accuracy of the numerical method is analyzed. Then the numerical programs for the models are designed by Visual C# in this paper, and the numerical solutions of the models are solved by the program. At last, taking the dual media model as an example, this thesis analyzes the influence the following factors on the pressure responses, including starting pressure gradient, media deformation, wellbore storage and skin factor. The variation rules of pressure are analyzed when considering or neglecting the starting pressure gradient and the deformation of the media And the sensitivity of starting pressure gradient and permeability modulus is comparatively analyzed. The pressure type curves are plotted too. The study has applicable value for well test analysis in the low permeability reservoir.更多还原