Quantifying Fluid Flow in Stressed & Fractured Carbonates

我们迫切需要在英国开发新的可再生能源，这将使国际社会与这些国家在发展道路上走得更远。我们的项目将利用意大利和德国的现有数据和专业知识，建立一个量化模型，将流经破裂石灰岩的流体与当地的地应力状态联系起来。地热能对英国具有潜在的重要性，因为下石炭统石灰岩(LCL)地层位于曼彻斯特、利物浦和布里斯托尔等大城市地区的地下，是一种可行的地热能源，尤其是用于供热。在LCL中，人们认为流体主要通过裂缝流动，而不是通过裂缝之间的岩石颗粒。这意味着我们需要更好地了解在深部自然应力作用下，裂隙灰岩中的流体是如何流动的。已经提出了几种不同的模型和方法来解释这种联系，但我们还不能在英国测试这些模型，因为我们缺乏关于裂缝网络、流体流速和两公里或更深处地应力的相关数据。与我们的意大利合作伙伴提出的这项新合作将使用之前对意大利南部-波滕萨附近的上阿格里山谷-石灰岩进行研究的大型数据集。可用的数据集包括裂缝、水井和油井的流体流量以及地应力。我们将整理所有这些数据，并在德国新项目合作伙伴的帮助下，建立一个农业山谷下破裂地下的数字3D模型，跨度为30x10x5公里(长x宽x深)。在这个模型中，我们将对裂缝施加应力(基于意大利的应力数据)，并预测从模拟井眼中流出的流体。通过将这些流体流量的模型预测与意大利钻孔的测量流量相比较，我们可以检验在应力石灰岩裂缝中流体流动的主要控制因素的相互竞争的假说。这就提供了一个科学可靠的基础，可以在此基础上建立未来对英国地下破裂和受压的石灰岩中潜在流体流动的分析。未来，我们将能够根据英国下石炭统石灰岩的具体情况，调整我们针对农业山谷的测试模型，以帮助公司和其他机构制定计划，为地热能源钻探安全且经济高效的钻孔。

We urgently need to develop new renewable energy sources in the UK, and this will take international collaboration with those countries further along the development path. Our project will build a quantitative model that links the fluid flow through fractured limestone with the local state of in situ stress, using existing data and expertise from Italy and Germany. Geothermal energy is potentially important for the UK because the Lower Carboniferous Limestone (LCL) formation underlies large urban areas, e.g., Manchester, Liverpool and Bristol, and is a viable source of geothermal energy, especially for supplying heat. In the LCL, it is believed that fluid flows mainly through fractures rather than through the rock grains in between the fractures. This means that we need to better understand how fluid flows in fractured limestones under natural stresses occurring at depth. Several different models and methods have been proposed to explain this linkage but we cannot test these models in the UK yet, because we lack the relevant data on the fracture networks, the fluid flow rates and the in situ stress at depths of two or more kilometres. This proposed new collaboration with our Italian partner will use large datasets from previous studies on limestones in southern Italy - the Upper Agri valley near Potenza. The datasets available cover fractures, fluid flow rates from water and oil boreholes, and in situ stresses. We will collate all these data and, with help from new project partners in Germany, build a digital 3D model of the fractured subsurface beneath the Agri valley, spanning 30 x 10 x 5 km (length x width x depth). In this model, we will impose stresses on the fractures (based on the stress data from Italy) and predict the fluid flow from simulated boreholes. By comparing these model predictions of fluid flow to the measured borehole flow rates from boreholes Italy we can test the competing hypotheses for the dominant controls on fluid flow in stressed limestone fractures. This then provides a scientifically robust foundation on which to build future analyses of potential fluid flow in the fractured and stressed limestones beneath the UK. In the future, we will be able to adapt our tested model for the Agri valley to the specifics of the UK Lower Carboniferous Limestone, to help companies and other agencies to develop their plans to drill safe and cost-effective boreholes for geothermal energy.