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基于物理过程法模拟沉积岩的沉积、压实和胶结过程,构建致密岩石的三维数字岩心。利用随机行走法模拟不同成岩过程岩石的核磁共振响应以及不同润湿性岩石孔隙中流体的核磁共振响应。模拟结果表明,岩石胶结成岩后孔隙半径减小导致核磁共振横向弛豫(T_2)分布的峰值向短弛豫方向移动,流体视扩散系数略小于自由扩散系数;致密岩石中随润湿相流体饱和度减小,润湿相T_2分布向短弛豫方向偏移,受限扩散越来越明显。
Deposition, compaction and cementation of sedimentary rocks are simulated based on physical processes to build three-dimensional digital cores of dense rocks. The random walk method was used to simulate the NMR responses of rocks with different diagenetic processes and the NMR responses of fluids in different wettability rocks. The simulation results show that the decrease of pore radius after rock cementation causes the peak value of transverse relaxation (T_2) of NMR to move in the direction of short relaxation, and the apparent diffusion coefficient of fluid is slightly less than that of free diffusion coefficient. With the saturation of wetting fluid in dense rock Degree decreases, the distribution of wetting phase T_2 shifts to the direction of short relaxation, and the restricted diffusion becomes more and more obvious.