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目前,研究并搞清构造裂缝的形成时间、位置、产状、规模及分布密度对于低渗透、超低渗透砂岩储层的勘探开发至关重要,但具有很大难度.基于应变能理论建立一套综合地质力学模型以定量预测裂缝参数及分布,如裂缝线密度和体密度等.首先,在岩石力学实验的基础上将脆性储层中由构造应力引起的总能量划分为裂缝表面能、摩擦耗能和残余应变能3种类型,其中前两者即为与裂缝产生相关的能量,并以此为桥梁推导建立应力-应变和裂缝参数之间的关系模型.其次基于地震解释结果建立复杂构造区含断层的古地质模型、岩石力学实验、测井解释,通过动静校正的方法获得砂岩、泥岩的强度参数,从而建立地质力学模型.最终,进行古应力场数值模拟计算裂缝参数三维展布特征,并以实际井点数据进行验证.结果表明地质力学模型法不同于一般的几何分析方法,具有较高的可靠性和适用性,能够预测不同构造运动阶段的裂缝参数分布,并能够进行三维空间显示;裂缝的充填程度不仅影响着裂缝开度,也在很大程度上影响着低渗透砂岩储层的渗流特征,这对于进一步实现现今裂缝开度的定量预测以及储层数值模拟具有重要意义.“,”Understanding and interpreting the timing,location,orientation,and intensity of natural fractures within a geological structure are commonly important to both exploration and production planning activities of low-porosity and low-permeability carbonate reservoirs.In this study,we explore the application of comprehensive geomechanical methods to quantitatively characterize the fracture parameters based on Strain Energy Density Theory,such as linear fracture density and volume fracture density.This study approach is based on the idea that energy generated by tectonic stress on brittle sandstone,which can be distinguished fracture surface energy,friction energy dissipation and residual strain energy and natural fractures can be interpreted or inferred from geomechanical-model-derived strains.For this analysis,we model an extension and compression compound fault block developed in a mechanically stratified sandstone and shale sequence because mechanics experimental data and drilling data exist that can be directly compared with model results.However,the results show that the approach and our study conclusion are independent of the specified structural geometry,which can correlate fracture parameters in different stages with different tectonic activities,and finally build and visualize fracture networks in sandstone.The presence or absence of filling minerals in fractures is shown to strongly control the destruction and transformation of low-permeability sandstone,and this control possesses crucial implications for interpreting fracture aperture and reservoir flow simulation.