Fluid pressure heterogeneity during fluid flow in rocks: new laboratory measurement device and method
Fluid pressure heterogeneity during fluid flow in rocks: new laboratory measurement device and method
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DOI：
10.1093/gji/ggab019
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发表时间：
2020-06
影响因子：
2.8
通讯作者：
N. Brantut;F. Aben
中科院分区：
文献类型：
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作者：
N. Brantut;F. Aben
提出了一种新型的传感器，能够在高围压条件下测量夹套岩样中的局部孔隙流体压力。传感器是无源的（基于应变计），尺寸小（与岩石接触的直径为7 mm，长度约为10 mm），并且具有最小的死体积（几mm3）。传感器测量封闭流体和内部孔隙压力之间的压差。该设计易于调整，可将灵敏度和工作压力范围调整至数百兆帕斯卡。在Darley Dale砂岩和Westerly花岗岩上进行静水压加压循环期间，对四个这样的换能器的阵列进行了测试。原型显示出非常好的线性度高达80 MPa，最大偏差的顺序为0.25 MPa，无论孔隙和围压的组合。多个内部孔隙压力的测量，使我们能够量化与Darley Dale砂岩断层相关的渗透率的局部下降，也证明了在低渗透性西风花岗岩瞬态流动过程中的孔隙压力前沿的跟踪发展是有用的。
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 mm3). 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 pressurization 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.