Effect of clay mineralogy and pore fluid chemistry on fluid flow in fault zones

了解断层在控制地下流体流动中的作用对许多地质应用至关重要。流体流动的滞后会导致超孔隙流体压力的发展，这将控制断层力学和地震成核。深层废物储存库的安全定位和从结构复杂的储层中回收碳氢化合物也取决于对地下流体流动的详细了解。先前的研究表明，含有粘土的断层岩与孔隙流体（特别是水）有显著的物理化学相互作用，可以影响它们在地壳上层的渗透性和强度。该项目的目的是测量高压和高温下粘土矿物学和孔隙水化学对断层岩石渗透率的潜在影响。本研究将结合矿物学和孔隙流体化学对高压高温下非膨胀性粘土流体流动特性影响的系统实验研究，以及对天然含泥断层岩的微观结构观察和矿物学表征。研究结果将用于发展和加强断层带流体流动的模型。

Understanding the role of faults in controlling subsurface fluid flow is of critical importance for a number of geological applications. Retardation of fluid flow can lead to the development of excess pore fluid pressures which will control fault mechanics and the nucleation of earthquakes. The secure positioning of deep waste repositories and the recovery of hydrocarbons from structurally complex reservoirs also depends on detailed understanding of subsurface fluid flow. Previous studies have suggested that fault rocks that contain clays have significant physicochemical interactions with pore fluids (in particular water) that can affect their permeability and strength at upper crustal levels. The aim of this project is to measure the potential effect of clay mineralogy and pore water chemistry at elevated pressures and temperatures on the permeability of fault rocks. This study will combine a systematic experimental investigation into the effect of mineralogy and pore fluid chemistry on the fluid flow properties of non-swelling clays under high pressure and elevated temperatures with microstructural observations and mineralogical characterization of naturally-occurring clay-bearing fault rocks. The results will be used to develop and enhance models of fluid flow through fault zones.