岩石断裂面曲折度影响下的粗糙单裂隙渗流规律

Seepage law of rough single fracture under the influence of tortuosity of rock fracture surface

针对岩石裂隙表面粗糙度对裂隙渗流性能影响的问题,采用数值模拟方法研究曲折度对粗糙单裂隙渗流影响的机理研究.结果表明:曲折度与流量修正系数和等效渗透系数修正系数呈正相关且相等,最大偏差为8%.对同裂隙开度不同粗糙元裂隙模型进行渗流模拟时,发现随着出入口压差的增大,立方定律的不适用性越来越明显,其中流体通过矩形粗糙元单裂隙沿程损失和局部损失最大,同时偏离立方定律也最为明显;将基于曲折度修正立方定律应用于预测矩形和三角形粗糙元粗糙单裂隙渗流,并与其他六种修正模型进行对比,发现基于曲折度修正立方定律在预测粗糙单裂隙时能获得更为准确的结果.

Aiming at the influence of the surface roughness of rock fissure on the seepage performance of fracture,the numerical simulation method was used to study the mechanism of the influence of tortuosity on the seepage of rough single fracture.The results show that the tortuosity is positively correlated with the flow correction coefficient and the equivalent permeability coefficient correction coefficient,and the maximum deviation is 8%.When the seepage simulation is carried out for different rough element fracture models with the same fracture opening,it is found that with the increase of the pressure difference between the inlet and outlet,the inapplicability of the cubic law becomes more and more obvious,and the fluid passes through the rectangular rough element single crack along the path loss and local loss.The maximum simultaneous deviation from the cubic law is also the most obvious.The modified cubic law based on tortuosity is applied to predict the rough single-fracture seepage of rectangular and triangular rough elements,and compared with the other six modified models,it is found that the modified cubic law based on tortuosity can obtain more accurate results when predicting rough single cracks.