论文标题
岩石流体流动过程中流体压力异质性：新的实验室测量装置和方法
Fluid pressure heterogeneity during fluid flow in rocks: New laboratory measurement device and method
论文作者
论文摘要
我们提出了一种新型的换能器，能够在升高压力条件下的外套岩石样品中测量局部孔隙流体压力。换能器是被动的（基于应变计的），小尺寸（与岩石接触时直径为7毫米，长度约为10毫米），并且死亡体积最少（几毫米$ $^3 $）。传感器测量限制流体和内部孔隙压力之间的差异。该设计很容易适应，以调整灵敏度和工作压力范围可达数百兆帕。在Darley Dale砂岩和Westerly花岗岩上的静静力加压循环中测试了四个这样的传感器的阵列。这些原型显示出非常好的线性性能高达80 MPa，而最大偏差为0.25 MPa，无论孔隙和限制压力的组合如何。多个内部孔隙压力测量值使我们能够量化与Darley Dale砂岩断层相关的渗透率的局部降低，并且也证明在低渗透率西北花岗岩中的短暂性流动过程中在跟踪孔隙压力方面的发展。
We present a new type of transducer capable of measuring local pore fluid pressure in jacketed rock samples under elevated confining pressure conditions. The transducers are passive (strain-gauge based), of small size (7 mm in diameter at the contact with the rock and around 10 mm in length), and have minimal dead volume (a few mm$^3$). The transducers measure the differential pressure between the confining fluid and the internal pore pressure. The design is easily adaptable to tune the sensitivity and working pressure range up to several hundred megapascals. An array of four such transducers was tested during hydrostatic pressurisation cycles on Darley Dale sandstone and Westerly granite. The prototypes show very good linearity up to 80 MPa with maximum deviations of the order of 0.25 MPa, regardless of the combination of pore and confining pressure. Multiple internal pore pressure measurements allow us to quantify the local decrease in permeability associated with faulting in Darley Dale sandstone, and also prove useful in tracking the development of pore pressure fronts during transient flow in low permeability Westerly granite.
