砾石充填层孔喉结构可视化模拟

砾石充填是防止疏松砂岩油藏在开采中出砂的主要方法之一，砾石层孔喉结构是选择砾石尺寸并预测其挡砂效果的重要参考依据。给定砾石颗粒的总数量，不考虑重力压实作用，在未沉降颗粒中随机抽取颗粒，进行沉降模拟，模拟过程包括沉降初始化、确定碰撞砾石颗粒、判断颗粒稳定性条件和运动趋势。统计模拟结果可得到充填层的可视化结构及孔喉直径的分布状况。用此方法两次模拟直径为0．4～0．8mm砾石随机沉降的二维充填，结果砾石层孔喉尺寸分布不符合正态分布规律，需要进一步探索其分布规律。对于同种砾石应多次模拟，将各次模拟结果加权平均后作为最终结果。

Visual simulation of porous structure in packed gravels

A certain number of suspending gravels are randomly selected to visually simulate sediment precipitation process. While sediment compaction due to gravity is not taken into consideration, the simulation procedures include precipitation initiation, selection of colliding grains, stability analysis, and moving trend prediction. The porous structure and throat size distribution can be derived from statistical analysis of the simulation data. In the present experiment, the simulation was conducted twice on gravels of 0.4 0.8 mm in diameter. Both sets of data indicate that the throat size did not demonstrate normal distribution. For a specific grain size, multiple simulations must be conducted and the data should be statistically treated in order to arrive at a reliable result.