Exploration of data space through trans-dimensional sampling: A case study of 4D seismics

Data repository in the article: "Exploration of data space through trans-dimensional sampling: A case study of 4D seismics" submitted to JGR: Solid Earth.

We consider a simple time-lapse scenario that consists of an overburden layer and a reservoir. To better mimic a real world application, we use a scaling factor of 10000 such that a frequency of 200 kHz represents a frequency of 20 Hz, and a dimension of 1 mm represents 10 m. To build this experiment in the lab we take two Plexiglas blocks with dimensions 310 x 154 x 77 mm, and attach them together. The first Plexiglas block represents the overburden layer with elastic properties of Vp = 2780 m/s, Vs = 1480 m/s, and rho = 1.19 g/cm3. This overburden layer remains unchanged between the two surveys. To build the reservoir layer we remove a rectangular cube from the second block, allowing us to insert different fluids into our "reservoir".

For the baseline survey, we keep the second block empty, representing a gas-filled reservoir. In this case, the elastic properties of the air are Vp = 332 m/s, V_s = N/A, and rho ~ 0 g/cm3. For the monitor survey, we fill the block with water, miming a scenario where the gas in the reservoir has been replaced with brine. The elastic properties of the water are Vp = 1500 m/s, Vs = N/A, rho ~ 1 g/cm3. For the source we use a P-wave transducer with a single-cycle sine wavelet at 200 kHz, generated through the function generator. This P-wave transducer has a diameter of 10~mm. For the receivers, we use a laser vibrometer that measures the particle velocity along the direction of the laser beam (perpendicular to the surface), and sends it to the oscilloscope to be saved. The laser measures the signal at 160 points along the tape, giving us a total of 160 receivers with a sampling distance of 0.5 mm. The nearest offset in this case is 10 mm. Throughout the data acquisition the P-wave transducer is glued to the Plexiglas box, and the laser is attached to a stage that stably moves it along the tape. This allows for a controlled and repeatable time-lapse experiment. Summarising, the experimental set-up allows us to record 160 "wiggles" for each of the two different reservoir-states, composing two "shot-gathers".

Directories contains the 160 wiggles recorded during the two different experiments

提交给JGR: Solid Earth的文章《跨维度采样探索数据空间：四维地震案例研究》中的数据集仓库。

我们构建了一套简单的时移实验场景，包含上覆地层与储集层。为更贴近实际应用场景，我们采用10000的缩放因子：200 kHz的模拟频率等效于实际20 Hz，1 mm的模型尺寸对应实际10 m的尺度。

本次实验室实验选用两块尺寸为310×154×77 mm的有机玻璃（Plexiglas）块并拼接组装。第一块有机玻璃块代表上覆地层，其弹性参数为纵波速度（Vp, P-wave velocity）2780 m/s、横波速度（Vs, S-wave velocity）1480 m/s，密度1.19 g/cm³。该上覆地层在两次观测中保持恒定不变。

为构建储集层结构，我们从第二块有机玻璃块中移除一个长方体空腔，可向其中注入不同流体以模拟储集层物性变化。

基准观测实验中，该空腔保持空置，代表含气储集层状态。此时空气的弹性参数为：纵波速度332 m/s，横波速度无有效数据（N/A），密度约为0 g/cm³。

监测观测实验中，我们向空腔内注入清水，模拟储集层内气体被盐水替换的工况。此时水的弹性参数为：纵波速度1500 m/s，横波速度无有效数据（N/A），密度约为1 g/cm³。

震源采用中心频率为200 kHz的单周期正弦子波纵波换能器（P-wave transducer），由函数发生器生成激励信号。该纵波换能器的直径为10 mm。

接收设备采用激光测振仪（laser vibrometer），可测量沿激光束方向（垂直于观测表面）的质点振动速度，并将采集数据传输至示波器存储。该激光测振仪沿测线共采集160个测点，等效为160个接收道，采样间距为0.5 mm。本次实验的最小偏移距为10 mm。

在整个数据采集流程中，纵波换能器固定粘接在有机玻璃箱体上，激光测振仪安装在可沿测线稳定移动的精密载物台上，从而实现可控且可重复的时移实验。

综上，该实验装置可针对两种储集层状态分别记录160道波形道（wiggles），共组成两套炮集记录（shot-gathers）。

本次数据集目录包含两次不同实验中采集的全部160道波形数据。