降低碳酸盐岩地层孔隙度和渗透率计算不确定性的方法

Reduction of uncertainty in calculation of porosity and permeability of carbonate rock.

碳酸盐岩储层受后期改造作用严重,使成岩作用、孔隙度、孔隙类型和声波速度之间相关性不强。用常规测井方法难以精确计算这种复杂储层的孔隙度和渗透率。介绍了提高碳酸盐岩孔隙度和渗透率计算精度的几种方法,即岩石物理反演法、数字图像分析技术、基于实验数据的渗透率模型法。这些新技术的应用实例表明:用岩石物理反演的孔隙度与岩心薄片的成像相吻合;用图像分析得到的大孔隙度在约束渗透率发散计算方面非常有用,使渗透率计算的不确定性降低2.5个数量级。将岩心实验测量、测井和地震相结合是提高孔隙度和渗透率等储层参数计算精度的发展方向。

Carbonate rocks show a lack of correlation between diagene sis, porosity, pore types and velocity due to intense alteration of the pore structure. Conventional logging methods fail to calculate the accurate porosity and permeability in such kind of complex reservoir. This paper introduced some methods that can accurately calculate the porosity and permeability of carbonate rocks. These methods are rock physical inversion, digital image analysis, and permeability model based on lab data. Applications of these methods show that porosity from rock physical inversion is in agreement with that from the thin section imaging, the macro-porosity from digital image analysis is useful in constraining permeability uncertainty, leading to the uncertainty of permeability calculation decreasing 2. 5 orders of magnitude. The author believe that the combination of core lab measurement, well logging, and seismic is the right way to reduce the uncertainty of calculation of reservoir parameters such as porosity and permeability.