基于岩石物理的等效弹性模量自适应估算方法研究

发布时间：2018-09-17 08:37

【摘要】：岩石物理主要研究岩石的储层特性与地震响应之间关系,是连接储层参数和岩石弹性参数之间的桥梁,有助于我们推断储层物性在横向或纵向的变化。岩石物理建模是用岩石物性参数来定量解释岩石的特性,进而预测岩石的弹性特征。本文在现有岩石物理模型基础上构建了可变干岩石骨架等效岩石物理模型,并充分考虑砂泥岩和碳酸盐岩储层特性,引入改进的快速模拟退火优化算法自适应反演等效弹性模量,并进一步实现储层横波预测。实验室数据和实际工区测井数据验证了模型的可靠性和适用性。干岩石骨架等效模量是进行储层纵横波速度预测重要的输入参数。本文在对现有干岩石骨架模型分析的基础上,引入含有可变参数的等效模量,并代入微分等效介质方程将解耦的微分方程组解耦为常微分方程组,再进一步化简推导了特殊形状包含物(球状、针状和硬币状裂缝)以及任意纵横比椭球状包含物的可变干岩石骨架等效岩石物理模型(VDEM,Variable Dry-Rock Equivalent Model)。对可变干岩石骨架等效模型的分析和测试表明,该模型灵活可变且适用性强,对干岩石骨架等效模量的预测精度高,并且可以结合Gassmann方程进行饱和岩石纵横波速度的估算。在经典的砂泥岩Xu-White模型基础上,本文进一步考虑孔隙几何形状等因素对纵横波速度的影响,基于推导的VDEM模型,对Xu-White模型进行改进,并结合改进的快速模拟退火优化算法自适应估算等效弹性模量,扩展了模型的适用性且提高了横波速度预测精确度。分别用砂泥岩实验室数据和测井数据对模型进行测试,结果表明改进的自适应等效模量预测模型较经典的Xu-White模型对砂泥岩储层横波速度预测精度更高、且模型的适用性更强。碳酸盐岩储层是重要的烃类储层之一,但沉积环境的改变和成岩作用等对碳酸盐岩岩石骨架及孔隙空间的改造使得碳酸盐岩储层速度和孔隙度关系很分散,与常规的砂泥岩储层相比碳酸盐岩储层非均质性更强,且具有更为复杂的微观结构,因此对碳酸盐岩储层的刻画更具有挑战性。在前人的研究成果,充分考虑碳酸盐岩储层非均质性及各向异性,结合VDEM模型,引入改进的快速模拟退火算法自适应反演等效弹性模量,再进行碳酸盐岩储层横波速度估算。碳酸盐岩实验室数据和测井数据验证了模型的有效性。
[Abstract]:Rock physics mainly studies the relationship between reservoir characteristics and seismic response of rock, which is a bridge between reservoir parameters and rock elastic parameters, which helps us to infer the variation of reservoir physical properties in horizontal or vertical direction. The physical modeling of rock is to quantitatively explain the characteristics of rock and then to predict the elastic characteristics of rock by using the physical parameters of rock. In this paper, an equivalent rock physical model of variable dry rock framework is constructed on the basis of existing rock physical models, and the characteristics of sand and mudstone and carbonate reservoir are fully considered. An improved fast simulated annealing optimization algorithm is introduced for adaptive inversion of the equivalent elastic modulus and the prediction of the reservoir shear wave is further realized. The reliability and applicability of the model are verified by laboratory data and actual area logging data. The equivalent modulus of dry rock skeleton is an important input parameter for prediction of compressional and shear wave velocity. Based on the analysis of existing dry rock skeleton models, the equivalent modulus with variable parameters is introduced, and the differential equivalent medium equations are substituted to decouple the decoupled differential equations into ordinary differential equations. Further simplification, equivalent rock physical model of variable dry rock skeleton (VDEM,Variable Dry-Rock Equivalent Model).) with special shape inclusions (spherical, needle-shaped and coin-shaped cracks) and ellipsoidal inclusions with arbitrary aspect ratio (VDEM,Variable Dry-Rock Equivalent Model).) is derived. The analysis and test of the variable dry rock skeleton equivalent model show that the model is flexible and adaptable, and the prediction accuracy of the equivalent modulus of the dry rock skeleton is high, and it can be combined with Gassmann equation to estimate the compressional and shear wave velocity of saturated rock. Based on the classical Xu-White model of sand and mudstone, this paper further considers the influence of pore geometry and other factors on the velocity of compressional and shear waves. Based on the derived VDEM model, the Xu-White model is improved. The adaptive estimation of the equivalent elastic modulus is combined with the improved fast simulated annealing optimization algorithm, which extends the applicability of the model and improves the prediction accuracy of the shear wave velocity. The model is tested by laboratory data and logging data. The results show that the improved adaptive equivalent modulus prediction model is more accurate than the classical Xu-White model in predicting shear wave velocity of sand and mudstone reservoir, and its applicability is stronger. Carbonate reservoir is one of the important hydrocarbon reservoirs, but the relationship between velocity and porosity of carbonate reservoir is dispersed due to the alteration of sedimentary environment and diagenesis on the framework and pore space of carbonate rock. Compared with conventional sandstone reservoir, carbonate reservoir has stronger heterogeneity and more complex microstructure, so it is more challenging to describe carbonate reservoir. Considering the heterogeneity and anisotropy of carbonate reservoir and combining with VDEM model, an improved fast simulated annealing algorithm is introduced to adaptively inverse the equivalent elastic modulus, and then the shear wave velocity of carbonate reservoir is estimated. The validity of the model is verified by carbonate rock laboratory data and logging data.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

【参考文献】