轮南地区奥陶系天然裂缝的发育机理及其对流体活动的控制

地下天然裂缝是导致地质灾害的主要原因之一 ,其机理研究是防灾的基础。轮南地区奥陶系天然裂缝的埋深在 5 0 0 0m以下 ,其发育受多种因素控制 ,且在地质演化过程中经历了多期发育而成 ,发育机理非常典型、复杂。笔者通过观察、描述岩心的裂缝发育特征 ,分析了深度、温度、围压等的变化以及剥蚀、裂缝充填对地下岩体力学性质的影响 ;进而建立综合数学模型 ,对裂缝发育概率分布和发育特点做出预测 ;根据计算结果 ,分析了轮南地区奥陶系天然裂缝的发育机理 ;通过天然裂缝分布与井内流体测试结果的对比分析 ,探讨了裂缝分布对地下流体活动的控制作用。

Developing Mechanism of Ordovician Natural Fracture and Its Control to Fluid Movement in Lunnan Area

Underground natural fracture is one of the main causes of geological disaster, and the mechanism research is the base of disaster prevention. In Lunnan area, the Ordovician natural fracture buries in a depth of 5000 meters. The formation of natural fracture is controlled by many factors with multi-stage development and colligation during geological evolution. So the mechanism is very typical and complicated. By observing and describing the fracture characteristics of cores, the impacts caused by denudation and filling, and the change of depth, temperature and confined pressure on mechanical property of underground rock are analyzed. It is on this basis, a mathematical model is constructed, and the probability distribution of fracture development and development characters are predicted. Based on the calculated results, and by analyzing the correlation between the distribution of natural fracture and the test results of fluid in wells, the control of underground fluid movement by fracture distribution is discussed.