Preface

After many years’ efforts, I finally make this book available to my colleagues and friends in the nuclear magnetic resonance community. Special thanks to the Royal Society of Chemistry and to the editors of this book.

Looking at the manuscripts, it reminds me of stories of many years ago when I started my career, the people and the days……

I started nuclear magnetic resonance study when I was a college student majoring in geophysical well logging at the Jianghan Petroleum Institute, China. In 1981, as a third-year university student, I completed fundamental courses and entered the professional course and was faced with the choice of the direction of my future research. For quite some time, I’ve been thinking, logging technology as a discipline, what is the fundamental problem with it? What is the body of knowledge and structure? How did it happen and develop? What are the research approaches and modes? As a result of my thinking, I tried to build a “log technology knowledge tree”. Where is the root of logging technology as a growing tree of knowledge? Where is the stem? Where will the flowers bloom? How can the roots be deep and leafy? It became a question that I kept thinking about. At the beginning of 1982, I finished my professional courses and gained a deeper understanding of these problems, realizing that the directions in which future logging technology may make greater breakthroughs in theory and application will include nuclear magnetic resonance logging, acoustic logging, and theory for logging data processing and interpretation. According to this understanding, when preparing for the graduation thesis of my bachelor’s degree, I combined my own strengths, chose NMR logging, and followed Prof. Gao Shoushuang, who was from Peking University and has supervising experience, and I began to study and explore this field. In the spring and summer of that year, classmates of mine and I were devoted to the investigation, translation, review and experimental research of NMR logging. We made dozens of artificial rock samples and used an old-fashioned electromagnet continuous wave low-field nuclear magnetic resonance instrument to establish a rock sample porosity measurement method. As a result of our labor, we edited and published a collection of nuclear magnetic logging translations, and the experimental results were published at the National Academic Exchange Conference on Rock and Mineral Physical Properties organized by the Chinese Geophysical Society in Shanghai in November 1982 (see Xiao Lizhi, Xie Hong, Determination of porosity of rock samples by Nuclear Magnetic Resonance, Proceedings on the Physical Properties of Rocks and Minerals, Beijing, Seismological Publishing House, 1988). We were encouraged by the initial results and prepared for a comprehensive and in-depth study of rock NMR and NMR logging. The leaders of the Jianghan Petroleum Institute have kept me to work and teach at the school after my graduation and plan to carry out work in this regard.

Unfortunately, however, under the conditions at that time, nobody was willing to provide any funding. For a high-tech field such as NMR logging, it is impossible to do anything without funding. So, I had to pause. In the five years from 1984 to 1989, I moved in another direction, namely logging explanatory theory. Supervised by Professor Liu Jiajin of China University of Mining and Technology, Professor Zhong Xingshui of Jianghan Petroleum Institute, Professor Yu Wenchi, and Academician Li Daqian of Fudan University, I conducted a comparative systematic study and research on the mathematical model and algorithm of the logging inversion problem, during which a series of papers were published. As I became more aware of the geophysical logging inversion problem, I felt even more passionate about the physical nature of the logging method. The effect of logging interpretation essentially depends on the reliability of the logging information, the correctness of the response equations, the completeness of the interpretation model, and, more importantly, the ability and sensitivity of the logging information to distinguish the parameters of the model. The solution of the inverse problem requires appropriate mathematical tools. Mathematics can help us to achieve data mapping and reduction from logging information space to model parameter space, but it cannot do “no rice cooking”. Mathematics is a necessary but not sufficient condition for logging inversion. From a mathematical point of view, in the solution of the system of well log response equations, increasing the information content (the number of equations) and reducing the influencing factors (the number of variables) have the same significance. However, in physics, if an observation can be found, which has no influencing factors unrelated to oil and gas evaluation, and has a relatively strong ability to distinguish the model parameters related to oil and gas characteristics, then this method will be of great significance for the logging interpretation aimed at oil and gas resource evaluation. This consideration often reminds me of NMR logging when studying logging inverse problems, because it is precisely such a method, on the one hand, without the influence of the rock mineral skeleton that is not related to the characteristics of oil and gas, and on the other hand, it has sensitive resolution of the type and state of the fluids in the pores.

Since 1990, the literature on NMR core analysis and NMR logging has increased significantly, and I have once again shifted my research interest to this field. In the spring of 1991, the Science and Technology Bureau of China National Petroleum Corporation held a meeting on the “Eighth Five-Year Plan” project “experimental research on rock and geophysical properties” in Beijing, and the leaders of the Exploration Bureau and the Science and Technology Bureau of CNPC supported me in declaring and undertaking the sub-project of “research on experimental methods for nuclear magnetic resonance of rock sample”, which greatly encouraged me. Even more fortunately, I took this project to the Wuhan Institute of Physics and Mathematics of the Chinese Academy of Sciences and studied for a doctorate degree in nuclear magnetic resonance under the supervision of highly respected scientists Ye Chaohui and Du Youru. The Wuhan Institute of Physics and Mathematics is the center of nuclear magnetic resonance theory and applied research in China, has a very good State Key Laboratory of Spectroscopy and Atomic and Molecular Physics, and has a group of outstanding scientists who are silently dedicated to exploration of new theory and new methods. The careful guidance and strict requirements of the instructors gave me the opportunity to systematically study and practice the basic theory, experimental methods, instrument principles and operations of nuclear magnetic resonance, and conduct comprehensive and in-depth research and exploration on the nuclear magnetic resonance properties of pore media and rock samples. In the process of learning and exploring, I have deepened my understanding of a passage from R. Ernst’s 1991 Nobel Prize in chemistry speech, saying that NMR is really a paradise, enabling theorists and people of all kinds of different backgrounds to find their own topics of interest and find their own places. It has so many attractive growth points that anyone who likes to explore new areas will be thrilled. Once, with the encouragement of Academician Tang Xiaowei, I was deeply attracted by the magnetic resonance imaging of human brain function and the magnetic resonance imaging of embryonic development.

In the early spring of 1993, Prof. Ye arranged for me to visit the United States. I participated in the 34th International Conference on Experimental Magnetic Resonance Imaging (ENC) with funding from the International Society of Magnetic Resonance, and visited the University of Utah, Colorado State University, Harvard University, Massachusetts Institute of Technology, Princeton University, and Schlumberger-Doll Research. At Schlumberger-Doll Research, I felt it the most. As an industrial research institution mainly engaged in well logging, they have achieved many high-level basic research results. Their NMR logging laboratory has always had a strong research force, and for decades, new results have emerged, leading the world trend of NMR research on porous media and rock samples. However, in the design of the underground NMR logging instrument, there was a considerable period of time hovering in the geomagnetic field scheme, affecting its commercialization process. From this, I thought about how important technological innovation is in the process of transforming basic research results into practical use and industrialization, it is not a simple problem that is directly applied, and it is necessary to find an appropriate way to achieve it, especially a wireline device with very harsh measurement conditions (high temperature, high pressure, state of motion, mechanical vibration) and strictly limited space volume. Of course, Schlumberger is, after all, a world-leading service company, and their combinable magnetic resonance logging (CMR) they developed in the early 1990s has attracted the attention of the oil industry for its good vertical resolution. In the autumn of 1994, Prof. Ye arranged for me to visit the United States again, and with the financial support of the Society of Petrophysicist and Well Logging Analysist SPWLA, I participated in the topic conference on “Application of Nuclear Magnetic Resonance in Logging and Formation Evaluation”, together with experts from all over the world on well logging and NMR in porous media, from oil companies and service companies. We spent five days intensively discussing relevant cutting-edge issues in NMR logging in depth. I was very impressed with this meeting. George Coates (NUMAR), Lawrence Schwartz (Schlumberger-Doll), Harold Vinegar (Shell), Robert Brown (Chevron, retired), Jasper Jackson (Los Alamos, retired) and other well-known experts and early pioneers of NMR logging came forward to introduce the latest methods and compare existing technologies, discussing the application effect, analyzing the development trend, and jointly designing the specific indicators of the ideal NMR logging instrument. The atmosphere of the meeting was very warm. NUMAR and Resonance Instruments demonstrated their benchtop NMR core analyzers, which aroused great interest among delegates. The daily meeting lasted from 8 a.m. to 10 p.m., and the venue was always full and there were rarely absences. After the conference, I spent three months studying with the Eiichi Fukushima group. During that time, Dr Jasper Jackson graciously led me to visit the famous Los Alamos National Laboratory, and told me stories about the development of NMR logging. Melvin Miller and George Coates invited me to visit NUMAR’s research center in Houston to introduce me to their new instruments and methods. Dr Russel Jacobs invited me to visit the California Institute of Technology. Dr Douglas Smith invited me to visit the Magnetic Resonance Laboratory at the University of New Mexico, where they are highly expert in the study of nuclear magnetic resonance in ceramics. In the spring of 1995, immediately after returning to China, I reported to both the China National Petroleum Corporation and the Chinese Academy of Sciences on the development of NMR logging in the world. The newly established CNPC Logging Co., Ltd. soon invited Mr George Coates, Vice President of NUMAR, to visit China.

In the autumn of 1995, I received a grant from the Royal Society, and in February 1996, I went to the Department of Chemistry at the University of Nottingham to conduct postdoctoral level research on “magnetic resonance study on quadrupole sodium in the process of non-mixed phase displacement of rock samples” under the supervision of Professor Ken Packer, former chief scientist of BP and Fellow of the Royal Society. During my time in the UK, I further felt that rock NMR and NMR logging were receiving a lot of attention. In addition to Professor Packer’s group, University of Cambridge and University of Kent have led their own teams to conduct research on NMR in porous media related to the petroleum industry. Their research was widely selected, well-funded and fruitful.

In the summer of 1996, I was invited by F. M. Dory to join Western Atlas International in London, where I was hired as NMR logging specialist and immediately sent back to Beijing to participate in commissioning two sets of NUMAR NMR logging instruments Atlas sold to China. On 6 July 1996, together with the operation engineers of CNPC Logging Company, I successfully completed the first NMR logging operation in China and obtained on-site NMR logging data. The successful acceptance announced the official start of China’s NMR logging work.

During the Chinese New Year of 1996 I completed a draft of an NMR logging book based on my PhD thesis. Then I combined part of my work at Nottingham and Western Atlas, the first NMR logging book, which was prefaced by Jasper Jackson, was published in 1998 (Xiao Lizhi, NMR Imaging Logging and Rock NMR, Science Press, Beijing). Later in 1998, George Coates, who has become my boss at Halliburton, visited Beijing and hosted a workshop on NMR logging at the Jianghan Well Logging Research Institute of CNPC, Hubei. During the workshop he got to know my NMR logging book and immediately decided to translate my Chinese book into English. After both George and myself returned to Houston, George initialed the book project and assigned me to lead the effort based on my book, which produced the Halliburton red book of NMR Logging Principles and Applications, co-authored by George Coates, Lizhi Xiao, and Manfred Prammer, which was made free to access for the public later in 1999. The red book is excellent and well received by the industry and universities. It has been the most cited literature in the well logging category for many years. More than twenty years have passed since it was published, however, the NMR logging technology has been evolving rapidly, and the tools, and the applications have been quickly iterated. Therefore, there is a strong demand to update the book. That was the initial intention for me to prepare this book, in which I will keep the classic part of the red book as it is, and integrate the most important progress beyond the red book.

It was a team effort to complete this book. Many of my colleagues at China National Petroleum Cooperation, China University of Petroleum, Halliburton, Harvard University, Schlumberger-Doll Research, and other institutions, have contributed a lot to this book, including, but not limited to, case study release and image permission. Both National Natural Science Foundation of China and CNPC have been continuedly providing financial support to make my research on NMR logging possible. The theses in NMR logging of more than one hundred students of mine made breakthroughs possible. Dr Sihui Luo helped a lot to finalize the manuscript and got the permissions granted.

The research and application of NMR logging are still developing quickly, and there is still a lot of work that we need to do, and there are many issues waiting for us to solve. Due to the uniqueness of the information provided by NMR logging, it will indeed give people a refreshing feeling at the beginning of application, and at the same time, it is easy to make people have too high expectations of it. In fact, on the one hand, it has changed the way logging oil and gas is evaluated to a certain extent, which has caused a boom and impact around the world; on the other hand, the problems in oil and gas exploration and development are too extensive and complex, and any single method cannot be a panacea, and the same is true for NMR logging, which will not become “aspirin”, let alone a panacea to solve all problems, and it will certainly find limitations in practice. We should treat this new method with a scientific attitude and the spirit of seeking truth from facts, treat it as a member of the family of logging, organically combine it with other effective methods, learn from each other’s strong points, and jointly solve the problems of geological analysis, oil and gas evaluation, and production dynamic monitoring in oil and gas exploration and development.

Lizhi Xiao