纳岭沟铀矿床洞穴增渗数值模拟研究

天然铀是保障我国核电发展和国防安全的重要战略资源，为满足国内日益紧迫的铀资源需求，解决制约低渗透砂岩型铀矿床原地浸出的技术瓶颈，本文提出了洞穴增渗技术方法，并研究了其在低渗透砂岩铀矿中的适用性。依托纳岭沟砂岩铀矿床，基于渗流、岩石力学理论构建了洞穴增渗作业数学模型，采用COMSOL软件对不同作业方式、作业次数下洞穴增渗形成的洞穴形态大小和渗透性改善情况进行了数值模拟研究。结果表明：连续作业方式效果优于恒定压力场作业方式，渗透性改善带主要发生在高压分布带控制范围内，10次洞穴增渗作业后渗透性改善带半径达20 m左右，钻孔附近渗透性改善倍数可达10~20倍。研究成果说明洞穴增渗技术在低渗透砂岩铀矿层中具有较好的效果，适用于提高我国低渗透砂岩铀矿床渗透性。

Numerical simulation of cave permeability enhancement in Nalinggou uranium deposit

Natural uranium is an important strategic resource to ensure the development of nuclear power and national security in China. To meet the increasingly urgent domestic demand for uranium resources and solve the technical bottleneck restricting in-situ leaching of the low-permeability sandstone-type uranium deposits, a cave permeability enhancement technology was proposed, and its applicability in low-permeability sandstone-type uranium deposits was investigated. Relying on the Nalinggou sandstone uranium deposit, a mathematical model of cave permeability enhancement operation was constructed based on the theories of seepage and rock mechanics. A numerical simulation study was carried out using COMSOL software for the improvement of cave size and permeability formed by the cave permeability enhancement under different operation methods and times. Results showed that the effect of continuous operation was better than that of the constant pressure field operation method. The permeability improvement zone mainly occurred in the control range of the high pressure distribution zone, the radius of the permeability improvement zone was approximately 20 m after 10 times of cave permeability enhancement operations, and the permeability improvement near the borehole can reach 10~20 times. The cave permeability enhancement technology has a better effect in the low-permeability sandstone uranium deposits, and is suitable for improving the permeability of the low-permeability sandstone uranium deposits in China.