基于岩石物理的裂缝型储层叠前地震反演方法研究

发布时间：2018-03-26 10:07

本文选题：裂缝型储层　切入点：各向异性　出处：《中国石油大学(华东)》2015年博士论文

【摘要】：地下裂缝是油气聚集和运移的重要通道。对于碳酸盐岩缝洞储层来说,准确的裂缝发育位置预测及裂缝充填物类型识别能够有助于提高油气储量计算的精度,而对于非常规储层,尤其是页岩气储层,可靠的裂缝特征描述有利于合理选择压裂开发位置,使得页岩地层通过压裂连通已有裂缝,形成网状结构,提高页岩气储层的产量。本文从地震各向异性的基本理论出发,列举了能够引起较强地震各向异性的地层类型,介绍了目前对地震各向异性强度衡量的各向异性参数(Thomsen参数)定义方法,并且分别给出了具有水平对称轴和具有垂直对称轴的横向各向同性介质的Thomsen参数定义式,同时利用岩石物理实验数据研究了三个各向异性参数之间的关系,为后续研究工作的开展奠定基础。从裂缝岩石物理理论出发,本文建立了适用于裂缝型储层的各向异性岩石物理等效模型。利用岩石物理等效模型,结合常规测井的解释结果(声波时差、密度、泥质含量、孔隙度及含水饱和度等),不仅可以估测出裂缝储层的纵横波速度,而且能够预测裂缝储层各向异性参数。同时,基于构建的裂缝岩石物理等效模型,本文研究了裂缝特征参数(裂缝密度、裂缝纵横比及裂缝充填流体类型)与裂缝岩石各向异性参数和裂缝岩石物理参数变化特征之间的关系。根据平面弹性波的反射与透射关系,本文介绍了各向异性介质反射系数精确值的求解方法,并选取了适用于各向异性介质地震反演的反射系数近似方程。通过构建不同的裂缝储层数值模型,研究了裂缝特征参数对反射系数特征的影响,探索了裂缝型储层反射系数AVAZ特征提取方法,并利用实际工区数据对该方法进行了验证,取得了较好结果。裂缝充填流体类型的预测是裂缝特征描述的重要内容。研究表明裂缝岩石物理参数与裂缝密度和裂缝充填流体类型密切相关,通过推导裂缝岩石物理参数与反射系数之间的近似关系式,探索裂缝岩石弹性参数和岩石物理参数的地震直接反演方法,同时分别利用测井数据合成记录和实际工区地震数据对裂缝岩石物理参数直接反演方法的精度进行了验证。结果表明,裂缝岩石物理参数地震直接反演方法具有较高的抗噪性,在实际目标工区弹性参数和裂缝岩石物理参数的估算中具有较好的应用结果。
[Abstract]:The underground fracture is an important channel for oil and gas accumulation and migration. For carbonate fracture-cavity reservoir, accurate prediction of fracture development location and identification of fracture filling type can help to improve the accuracy of oil and gas reserves calculation. For unconventional reservoirs, especially for shale gas reservoirs, reliable description of fracture characteristics is conducive to the rational selection of fracturing development sites, which makes shale formations connected to existing fractures through fracturing to form a network structure. Based on the basic theory of seismic anisotropy, the types of strata which can cause strong seismic anisotropy are listed in this paper. The definition method of anisotropic parameter Thomsen parameter is introduced, and the Thomsen parameter definitions of transversely isotropic medium with horizontal axis and vertical axis are given, respectively. At the same time, the relationship between the three anisotropic parameters is studied by using the experimental data of rock physics, which lays a foundation for further research work. In this paper, an anisotropic physical equivalent model for fractured reservoirs is established. Using the physical equivalent model of rock, combined with the interpretation results of conventional logging (acoustic moveout, density, mud content, etc.). Porosity and water saturation can not only estimate the longitudinal and shear wave velocities of fractured reservoirs, but also predict anisotropic parameters of fractured reservoirs. In this paper, the fracture characteristic parameters (crack density) are studied. The relationship between fracture aspect ratio and fracture filling fluid type) and the variation characteristics of anisotropy parameters of fractured rock and fracture rock physical parameters, according to the reflection and transmission relation of plane elastic wave, In this paper, the method of solving the exact value of reflection coefficient in anisotropic medium is introduced, and the approximate equation of reflection coefficient suitable for seismic inversion of anisotropic medium is selected. Different numerical models of fractured reservoir are constructed. In this paper, the influence of fracture characteristic parameters on reflection coefficient is studied, and the AVAZ feature extraction method of fractured reservoir reflection coefficient is explored, and the method is verified by actual working area data. Good results have been obtained. The prediction of fracture filling fluid type is an important part of fracture characteristics description. The study shows that fracture rock physical parameters are closely related to fracture density and fracture filling fluid type. By deducing the approximate relation between fracture rock physical parameters and reflection coefficient, the seismic direct inversion method of fracture rock elastic parameters and rock physical parameters is explored. At the same time, the precision of the direct inversion method of fracture rock physical parameters is verified by combining log data and seismic data of actual working area. The results show that the seismic direct inversion method of fracture rock physical parameters has high noise resistance. It has good application results in the estimation of elastic parameters and fracture rock physical parameters in actual target area.
【学位授予单位】：中国石油大学(华东)
【学位级别】：博士
【学位授予年份】：2015
【分类号】：P618.13;P631.4

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