GOALI: The use of logging and surface NMR measurements to estimate hydraulic conductivity in unconsolidated aquifers

测井和地面核磁共振测量用于估算未固结含水层的水力传导率Rosemary Knight（PI），斯坦福大学Yi-Qiao Song（Co-PI），Schlumberger-Doll研究全球范围内，人们越来越关注地下水资源的可持续性。为了管理和保护我们的水资源，必须作出关键的决定，这需要准确地描述地下水含水层的特性，因为地下水含水层控制着水的储存和流动。该研究项目的重点是使用NMR（核磁共振）测井和地面NMR作为一种手段，确定水力传导性（K）在饱和区的松散含水层从NMR弛豫时间的测量。NMR测井涉及将仪器降低到钻孔中以测量周围地质材料的孔隙水中的氢质子的NMR弛豫时间。NMR测井已用于石油应用多年，以估计石油储层的性质，例如充水孔隙度、孔径分布和渗透率。现在有一个越来越多的兴趣在使用核磁共振测井地下水的应用，以获得估计K在松散或弱固结含水层材料。在我们的研究中要解决的一个关键问题：我们如何才能获得可靠的估计K从NMR测井测量松散含水层？在过去的十年里，人们对一种新的、非常不同的利用地球进行核磁共振测量的方法产生了极大的兴趣。的磁场和位于表面的系统。一种非侵入性的，基于地表的核磁共振方法，被称为磁共振测深（MRS），已被开发并用于测量地下水含水层的核磁共振响应，并获得K的估计。有两个突出的问题，将在这项研究中解决这项技术：什么是实际测量的参数，目前采取代表的NMR弛豫时间在MRS测量？我们如何从未固结材料的MRS测量中获得K的可靠估计？我们的愿景和研究的动机是开发一种新的基于NMR的含水层表征方法，该方法1）基于对NMR响应与松散材料K之间关系的更好理解，2）以综合方式建立在两种技术的最佳基础上。我们的方法将使我们能够探索新的方法，整合两种形式的核磁共振测量，以获得改进的地下模型的核磁共振性能，和K。我们的研究包括实验室实验和数值模拟。此外，我们将在内布拉斯加州的列克星敦附近进行一项现场实验，在那里将对90至120米厚的奥加拉拉含水层进行测井和地面核磁共振测量。该提案提供了一个独特的合作机会，它将斯坦福大学的一个研究小组、美国地质调查局的一个研究小组、一个正在进行的MRS研究项目、一个在NMR实验室测量、理论和建模方面具有专门知识的研究小组、一个正在进行的MRS研究项目和一个在NMR实验室测量、理论和建模方面具有专门知识的研究小组聚集在一起。以及主要的工业合作伙伴，斯伦贝谢-多尔研究公司（SDR）和斯伦贝谢水务公司（SWS），在核磁共振测井的采集和解释方面拥有专业知识，和Vista Clara公司，在获取和解释MRS数据方面具有专业知识。

THE USE OF LOGGING AND SURFACE NMR MEASUREMENTSTO ESTIMATE HYDRAULIC CONDUCTIVITY IN UNCONSOLIDATED AQUIFERSRosemary Knight (PI), Stanford UniversityYi-Qiao Song (Co-PI), Schlumberger-Doll ResearchThere are growing concerns, worldwide, about the sustainability of our groundwater resources. The critical decisions that must be made, in order to manage and protect our water resources, require accurate characterization of the properties of groundwater aquifers that govern both the storage and movement of water. The focus of this research project is the use of NMR (nuclear magnetic resonance) logging and surface-based NMR as a means of determining hydraulic conductivity (K) in the saturated zone of an unconsolidated aquifer from measurement of NMR relaxation times. NMR logging involves lowering an instrument into a borehole to measure the NMR relaxation times of hydrogen protons in the pore water of the surrounding geological material. NMR logging has been used for many years for petroleum applications to estimate the properties of petroleum reservoirs such as water-filled porosity, pore-size distribution, and permeability. There is now a growing interest in the use of NMR logging for groundwater applications to obtain estimates of K in unconsolidated or weakly consolidated aquifer materials. A key question to be addressed in our research: How can we obtain reliable estimates of K from NMR logging measurements in unconsolidated aquifers?Over the past decade, there has been great interest in a new, and very different way of making NMR measurements using Earth?s magnetic field and a system located at the surface. A non-invasive, surface-based NMR method, referred to as magnetic resonance sounding (MRS), has been developed and used to measure the NMR response of groundwater aquifers and obtain estimates of K. There are two outstanding questions related to this technology that will be addressed in this research: What is actually measured as the parameter currently taken to represent the NMR relaxation time in the MRS measurement? How can we obtain reliable estimates of K from MRS measurements in unconsolidated materials? Our vision, and the motivation for the research, is the development of a new approach to NMR-based aquifer characterization that 1) is grounded in an improved understanding of the relationship between the NMR response and K of unconsolidated materials and 2) builds on the best of both technologies in an integrated way. Our approach will allow us to explore new ways of integrating the two forms of NMR measurement to obtain improved subsurface models of NMR properties, and of K. Our proposed research includes laboratory experiments and numerical modeling. In addition, we will conduct a field experiment near Lexington, Nebraska where both logging and surface-based NMR measurements will be made over the 90 to 120 m thick Ogallala aquifer. This proposal represents a unique opportunity for collaboration by bringing together a research group at Stanford, with expertise in NMR laboratory measurements, theory and modeling; a research group at the U.S. Geological Survey with an ongoing project to study MRS; and key industrial partners, Schlumberger-Doll Research (SDR) and Schlumberger Water Services (SWS), with expertise in the acquisition and interpretation of NMR logging, and Vista Clara, Inc., with expertise in the acquisition and interpretation of MRS data.