Analog laboratory experiments of the formation of forced folds and sand injections driven by pore fluid overpressure

Sand injections form by intrusion of overpressured, fluidized sand into surrounding low-permeable, fine-grained rocks. We conducted a series of scaled analog experiments to investigate the kinematic evolution of sand injections originating from an overpressured, tabular source layer associated with forced folding and propagation of fractures. The experiments were performed in the analog laboratory of the Institute of Geosciences (Friedrich Schiller University Jena) in the framework of the project "Mobilization of Unconsolidated Sediments Related to CO2 Storage". The layering of the analog materials consisted of non-cohesive and cohesive granulates to mimic a sand reservoir and its fine-grained overburden. To produce a fluid overpressure in the layered materials, air was injected from the base of the reservoir layer and additionally through a point-like needle valve penetrating into the reservoir layer. Pressure sensors recorded the air pressure at the base of the reservoir layer and in the needle valve. The experiments were monitored with a digital SLR camera and analyzed by the digital image correlation software DaVis 10.0 (LaVision GmbH) to calculate displacement and strain patterns in the analog materials. The data set presented here includes (1) original data: - Photos of the experimental evolution - Data of volumetric air flow rate and air pressure recorded during the experiments and (2) analyzed data: - Results of digital image correlation including edited photographs as well as data and plots of the displacement vector fields - Edited photos and a Python script for analyzing the vertical displacements of the experimental surface. Detailed descriptions of the experiments, method and results can be found in Warsitzka, et al. (2019) to which this data set is supplement.砂贯入体（sand injections）系超压流态化砂侵入周边低渗透性细粒岩石所形成的构造。本研究团队开展了一系列定比例尺类比实验，以探究源自超压板状源层的砂贯入体的运动学演化过程，该源层与断裂的强制褶皱及扩展过程直接相关。本实验在耶拿弗里德里希·席勒大学地球科学研究所类比实验室完成，隶属于"与二氧化碳封存相关的未固结沉积物活化"（Mobilization of Unconsolidated Sediments Related to CO2 Storage）项目。类比材料的层理体系由非黏结性与黏结性颗粒构成，用以模拟砂质储层及其上覆细粒盖层。为在层状材料中构建流体超压环境，我们从储层底部注入空气，同时通过插入储层的点状针阀进行辅助注气。压力传感器同步记录了储层底部及针阀处的空气压力数据。实验采用数码单反相机（digital SLR camera）进行全程监测，并借助数字图像相关（digital image correlation）软件DaVis 10.0（LaVision GmbH公司）完成分析，以计算类比材料内的位移与应变分布场。 本数据集涵盖两类数据： (1) 原始数据： - 实验演化过程的系列照片 - 实验期间记录的空气体积流量与压力数据 (2) 分析后数据： - 数字图像相关分析结果，包括编辑后的实验照片、位移矢量场数据与对应绘图 - 编辑后的实验照片，以及用于分析实验表面垂直位移的Python脚本。 本数据集为Warsitzka等人（2019）的研究成果的配套补充数据集，该文献详细记载了本实验的具体方案、研究方法与最终结果。