花岗岩潜山裂缝型储层多尺度建模与应用

当前对花岗岩裂缝型储层的表征尚未形成系统、完善的方法，受风化、岩性、构造等多种因素影响，花岗岩储层内部孔、缝、洞发育，具有极强的非均质性，更增加了对其表征的难度。为此，以乍得花岗岩潜山B油田为例，提出一种多尺度裂缝建模方法，该方法将确定性建模与随机建模方法相结合，运用叠前全方位AVAZ反演裂缝预测结果和叠后蚂蚁追踪裂缝预测成果，在裂缝地震相的控制下，分别建立小尺度裂缝和大尺度裂缝模型，前者可得到各向异性参数及裂缝密度、方向等参数，通过这些参数对裂缝型储层进行识别及评价，后者在地震数据上进行裂缝片的识别与追踪，识别出的每根裂缝具有可度量的长度和方向；然后利用等效裂缝模型实现对裂缝渗透率的定量表征；紧密结合地震叠后、叠前全方位地震数据裂缝预测成果与开发地质，并充分融合测井、地质、钻井、生产等资料，形成综合反映不同尺度裂缝信息的系统裂缝模型。该裂缝模型为开发井优化部署提供了技术依据，多尺度裂缝模型等效渗透率计算结果更符合流体渗流特征，为开发油藏数值模拟奠定了基础。

Multi-scale modeling of granite buried-hill fractured reservoir and its application

At present, there is no systematic and perfect method for the characterization of granite fractured reservoirs. Influenced by weathering, lithology, structure, and other factors, the development of pores, fractures, and caves in the reservoirs is highly heterogeneous, which increases the difficulty of their characterization. Therefore, taking the granite buried-hill B oilfield in Chad as an example, this paper proposes a multi-scale fracture modeling method. The method combines the deterministic modeling method with the stochastic modeling method and uses the results of fracture prediction based on pre-stack omnidirectional AVAZ (amplitude variations with azimuths) inversion and those based on post-stack ant tracking to establish a small-scale fracture and a large-scale fracture model respectively under the control of the fracture seismic facies. The former can provide anisotropy parameters, fracture density, direction, and other parameters, with which fractured reservoirs can be identified and evaluated. The latter can identify and track fractures on the seismic data, and each identified fracture has measurable length and direction. Furthermore, the equivalent fracture model is used to realize the quantitative characterization of fracture permeability. The results of comprehensive fracture prediction with post-stack and pre-stack seismic data are closely combined with the development geology, and well logging, geological, drilling, and production data are fully integrated to form a systematic fracture model that can comprehensively reflect the fracture information on different scales in various data. The fracture model provides a technical basis for the optimization of development well deployment, and the equivalent permeability calculation results of the multi-scale fracture model are more consistent with the characteristics of fluid flow, which lays a foundation for the numerical simulation of reservoirs.