Experimental compaction of quartz sand at low effective stress and temperature conditions
Experimental compaction of quartz sand at low effective stress and temperature conditions
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低有效应力和低温度条件下石英砂压实试验
DOI：
10.1144/gsjgs.148.3.0527
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发表时间：
1991
影响因子：
2.7
通讯作者：
P. Schutjens
中科院分区：
文献类型：
--
作者：
P. Schutjens
实验已经进行了干燥和流体饱和的石英砂，以调查在压实成岩条件下的行为，并评估的重要性，应力引起的解决方案转移（“压力解决方案”）作为一种压实机制。实验在温度（T）在150-350°C范围内、施加的有效应力（σe）高达20.7 MPa和孔隙流体压力（P1）为12.5和15.5 MPa下进行，使用具有在20-100 μm范围内的晶粒尺寸（d）和45- 52%的初始孔隙度的材料。干石英砂在加载阶段经历了显著的压实，但一旦达到满载，则表现出非常小的压实蠕变（即，基本上与时间无关的压实）。与此相反，流体饱和的材料在恒定施加的有效应力表现出大量的时间依赖性压实（即蠕变）。随着温度的升高，湿压实砂中出现晶内裂纹的颗粒数量减少，而与相邻颗粒接触处出现溶解特征的颗粒数量增加。此外，随着体积应变（ev）和σe的增加，体积应变率β对σe的依赖性逐渐减小，随着温度的升高，β对ev的依赖性逐渐减小。这些观察结果表明，对于湿石英砂，可能会发生逐渐的变化，从压实蠕变控制的时间依赖性的微裂纹，在T = 250-300 °C，压实蠕变控制的应力诱导的晶间溶液转移，在T = 300-350 °C。
Experiments have been carried out on dry and fluid-saturated quartz sands to investigate the behaviour during compaction under diagenetic conditions and to evaluate the importance of stress-induced solution transfer ('pressure solution') as a compaction mechanism. The experiments were performed at temperatures (T) in the range 150–350°C, applied effective stresses (σe) up to 20.7 MPa and pore fluid pressures (P1) of 12.5 and 15.5 MPa, using material with a grain size (d) in the range 20–100 μm and an initial porosity of 45–52%. Dry quartz sands underwent significant compaction during the loading stage, but showed very little compaction creep once full load was achieved (i.e. essentially time-independent compaction). In contrast, fluid-saturated material at constant applied effective stress showed substantial time-dependent compaction (i.e. creep). With increasing temperature, there is a decreasing number of grains in the wet-compacted sand which show intragranular cracks and an increasing number of grains which show dissolution features at contacts with adjacent grains. In addition, there is a decreasing dependence of the volumetric strain rate, β on σe, with both increasing volumetric strain (ev) and increasing σe and a decreasing dependence of β on ev with increasing temperature. These observations suggest that, for wet quartz sand, a gradual change might occur from compaction creep controlled by time-dependent microcracking, at T = 250–300 °C, to compaction creep controlled by stress-induced intergranular solution transfer at T = 300–350 °C.