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

利用测井和地表核磁共振测量来估算松散含水层的水力导电性罗斯玛丽·奈特（PI），斯坦福大学，宋一乔（Co-PI），斯伦贝谢- doll研究在世界范围内，地下水资源的可持续性越来越受到关注。为了管理和保护我们的水资源，必须做出的关键决定，需要准确地描述地下水含水层的特性，这些特性控制着水的储存和流动。该研究项目的重点是利用核磁共振测井和地面核磁共振作为一种手段，通过测量核磁共振弛豫时间来确定疏松含水层饱和带的水力导电性(K)。核磁共振测井包括将仪器放入井中，测量周围地质物质孔隙水中氢质子的核磁共振弛豫时间。多年来，核磁共振测井一直应用于石油领域，用于估计油藏的性质，如充水孔隙度、孔隙尺寸分布和渗透率。现在人们对利用核磁共振测井在地下水中的应用越来越感兴趣，以获得松散或弱胶结含水层材料中钾的估计值。在我们的研究中需要解决的一个关键问题是：我们如何从松散含水层的核磁共振测井测量中获得可靠的K估计？在过去的十年里，人们对利用地球进行核磁共振测量的一种新的、非常不同的方法产生了极大的兴趣。S磁场和一个位于地表的系统。一种非侵入性的、基于表面的核磁共振方法，被称为磁共振测深（MRS），已经被开发出来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。与该技术相关的两个突出问题将在本研究中得到解决：在MRS测量中，目前用来表示核磁共振弛豫时间的参数实际测量的是什么？我们如何从松散材料的MRS测量中获得可靠的K估计？我们的愿景和研究动机是开发一种基于核磁共振的含水层表征新方法，该方法1)基于对未胶结材料的核磁共振响应与K之间关系的更好理解，2)以综合的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整合两种形式的核磁共振测量的新方法，以获得改进的核磁共振性质和k的地下模型。我们建议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列克星敦附近进行现场实验，在那里将对90至120米厚的Ogallala含水层进行测井和地面核磁共振测量。该提案代表了一个独特的合作机会，将斯坦福大学的一个研究小组聚集在一起，在核磁共振实验室测量、理论和建模方面具有专业知识；美国地质调查局的一个研究小组正在研究MRS；以及主要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）在核磁共振测井采集和解释方面的专业知识，以及Vista Clara公司在MRS数据采集和解释方面的专业知识。

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.