Lei Li

Lei Li
Central South University | CSU · School of Geoscience and Info-Physics

Ph.D.

About

43
Publications
11,136
Reads
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392
Citations
Citations since 2016
41 Research Items
390 Citations
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2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
Introduction
Lei Li currently works at the School of Geosciences and Info-Physics, Central South University. Lei does research in microseismic/induced seismicity monitoring and hydraulic fracturing. His current research projects/topics include 'Efficient microseismic inversion of shale hydraulic fracturing' and 'Seismic forward modeling and source imaging of induced seismicity at multiple scales'.
Additional affiliations
September 2016 - September 2017
University of Hamburg
Position
  • PhD Student
Education
September 2012 - January 2018
University of Chinese Academy of Sciences
Field of study
September 2008 - July 2012

Publications

Publications (43)
Article
Horizontally transverse isotropy (HTI) induced by vertical or subvertical, aligned fractures is common for unconventional fractured porous shale oil or gas reservoirs. Compared with the unfractured rocks, the seismic response characteristics of PP-wave azimuthal amplitudes are usually disturbed by the fractures and the in-situ stresses. Knowledge o...
Article
Full-text available
Reservoir monitoring is necessary to achieve safe hydrocarbon extraction. It requires monitoring small acoustic emission (AE) events, assisting in determining the exact location, extension and direction of potential damage as early as possible. However, microcracks cannot be detected by the microseismic monitoring networks due to the limitations of...
Article
Microporous structure and pore fluid are two important components of poroelastic rocks that influence the variation of rock modulus. Cracks are special microstructures that are more likely to be compressed during wave propagation than stiff pores, resulting in squirt flow. In addition, the distribution of different fluids, such as water and gas, ma...
Conference Paper
Unconventional geo-energy resources, such as shale gas and geothermal energy, are supposed to play an essential role in energy transition and carbon neutrality. Currently, hydraulic fracturing is still the dominant stimulation strategy to obtain economic production. Hydraulic fracture (HF) propagation behavior is significant to characterize the res...
Article
Full-text available
波形叠加定位法具有自动性和抗噪性等优点,已被广泛应用于微地震事件定位.当该类方法采用特征函数变换原始波形以克服初至极性变化影响时,会降低成像分辨率.而将相位加权叠加法应用于微地震成像时,虽然提高了成像分辨率,但并未考虑复杂震源机制对定位的影响.为了校正波形极性,并提高干涉成像法的分辨率和压制噪声的能力,本文重新组合了原始互相关波形的振幅和瞬时相位信息,提出了互相关相位加权成像法(CCPW).通过数值算例对比了互相关相位加权成像法(CCPW)、基于绝对值干涉成像法(AII)和基于长短时窗能量比干涉成像法(SLII),讨论了不同方法在抗噪性和成像分辨率等方面的性能.理论测试结果表明:新方法能够校正波形极性变化,具有较强的抗噪性,提高了成像分辨率.最后将三种方法应用于地面监测的实际矿震数据中,验证...
Preprint
Full-text available
Seismology focuses on the study of earthquakes and associated phenomena to characterize seismic sources and Earth structure, which both are of immediate relevance to society. This article is composed of two independent views on the state of the ICON principles (Goldman et al., 2021) in seismology and reflects on the opportunities and challenges of...
Article
Full-text available
Pointing to the ICON-FAIR principles, we have determined several opportunities for implementation within the realm of near-surface geophysics (NSG), representing a broad range of data acquisition and processing technologies. Our work explores the multifaceted community-driven nature of NSG and, by applying ICON-FAIR principles, we identify three ke...
Article
Full-text available
Seismology focuses on the study of earthquakes and associated phenomena to characterize seismic sources and Earth structure, which both are of immediate relevance to society. This article is composed of two independent views on the state of the ICON principles (Goldman et al., 2021) in seismology and reflects on the opportunities and challenges of...
Article
Hydraulic fracture (HF) propagation behavior is significant when building enhanced geothermal systems (EGS). HF geometry is closely related to the structural planes (SPs) in hot dry rock (HDR), such as natural fractures (NFs), quartz veins (QVs) and lithologic interfaces (LIs). However, the HF behaviors in HDR have not been well understood, especia...
Poster
Full-text available
Seismic source locations provide fundamental information on earthquakes and lay the foundation for seismic monitoring at all scales. Subsurface engineering operations, such as hydraulic fracturing, usually generate abundant microseismic events with low signal-to-noise ratios, thus raising a higher demand on the reliability and computational efficie...
Conference Paper
Full waveform inversion (FWI) is the latest seismic imaging method, which provides high-resolution seismic models to explain observations based on the iterative reduction of misfit between the observed and simulated records. Conventional approaches for FWI model-resolution assessment and inter-parameter trade-off analysis are routinely performed by...
Chapter
Chapter 8 by Li et al. considers the importance of microseismic technology in monitoring many subsurface engineering operations, including shale hydraulic fracturing, fluid injection and extraction, and geological storage of carbon dioxide. The basic principles and technical workflow of microseismic monitoring for reservoir characterization are exp...
Article
Full-text available
Seismic modeling plays an important role in geophysics and seismology for estimating the response of seismic sources in a given medium. In this work, we present a MATLAB-based package, FDwave3D, for synthetic wavefield and seismogram modeling in 3D anisotropic media. The seismic simulation is carried out using the finite-difference method over the...
Article
Commonly-used seismic fracture characterization method assumes one single fracture set, and this article aims to relax the limitation and demonstrate the feasibility of seismic characterization for two sets of orthorhombic fractures. Elastic properties of orthorhombic fractures can be studied using a model of horizontal and vertical fractures as li...
Article
Full-text available
The development of hydraulic fracturing and horizontal drilling techniques has promoted the exploitation of shale gas resources. However, using water has several potential drawbacks including environmental issues, e.g., the contamination of groundwater, surface water, and soil, and poor hydrocarbon recovery. Supercritical carbon dioxide (SC-CO2), w...
Article
Full-text available
Seismic source location specifies the spatial and temporal coordinates of seismic sources and lays the foundation for advanced seismic monitoring at all scales. In this work, we firstly introduce the principles of diffraction stacking (DS) and cross-correlation stacking (CCS) for seismic location. The DS method utilizes the travel time from the sou...
Article
Full-text available
Fracture characterization is essential for estimating the stimulated reservoir volume and guiding subsequent hydraulic fracturing stimulations in shale reservoirs. Laboratory fracturing experiments can help provide theoretical and technical guidance for field operations. In this study, hydraulic fracturing experiments on the shale samples from Niut...
Article
Understanding the differences among shale pore systems is crucial to exploring the enrichment mechanism of shale gas. In this study, we found that radiolarian micro-fossils are widely distributed in the overmature marine organic-rich Wufeng-Lungmachi formations surrounding the Sichuan Basin, South China. This enables an investigation on the full-sc...
Article
Full-text available
Hydraulic fracturing is a widely used technique for oil and gas extraction from ultra-low porosity and permeability shale reservoirs. During the hydraulic fracturing process, large amounts of water along with specific chemical additives are injected into the shale reservoirs, causing a series of reactions the influence the fluid composition and sha...
Article
Our planet is continually being affected by natural and human-induced seismic events causing shaking, rupturing, and cracking at Earth’s surface. These seismic waves are detected and recorded by different kinds of instruments, which reveal information about their spatial and temporal origin. A recent article in Reviews of Geophysics explores the po...
Article
Full-text available
Source locations provide fundamental information on earthquakes, and lay the foundation for seismic monitoring at all scales. Seismic source location as a classical inverse problem has experienced significant methodological progress during the past century. Unlike the conventional traveltime-based location methods which mainly utilize kinematic inf...
Poster
Full-text available
Laboratory acoustic emission (AE) monitoring has the potential of detecting the spatial-temporal onset of fracturing and revealing the evolution characteristics of fractures in different rock types and under different loading conditions. In this work, we use waveform-based techniques, including time-frequency analysis of the waveforms, waveform sta...
Conference Paper
In the past three years, some moderate-sized earthquakes (M W >4.0) took place in the southern Sichuan Basin, China and were suspected to be associated with hydraulic fracturing stimulation for producing the shale gas. The objective of this study is to investigate the relation between an earthquake sequence and hydraulic fracturing stimulation at t...
Article
Full-text available
A better understanding of the stress–strain behaviors of shale samples after shale-CO2 or shale-water–CO2 interactions is of great importance to CO2 enhanced shale gas exploitation and CO2 sequestrating in shale reservoirs. In this study, a constitutive model that combines with the modified Duncan–Chang model and Weibull distribution-based model is...
Article
Carbon dioxide (CO 2 ) is a promising fluid which can be used for shale gas recovery. In this study, uniaxial compressive strength tests were performed on low-clay shale samples soaked in sub-/or super- critical CO 2 and its dissolved water/brine solutions for 10, 20 and 30 days. The deformation and crack evolution during the experiments were analy...
Conference Paper
Automatic event detection is of vital importance for real-time microseismic or passive seismic monitoring in the oil and gas industry. With the recent advances in artificial intelligence and computing power, deep learning has now become a reliable tool for automatic microseismic event detection and other problems. We present a novel “classification...
Conference Paper
Fast and accurate source location is crucial for microseismic monitoring. Stochastic optimization algorithm is derivative-free and just need random solutions as the initial model, and it is quite suitable for non-linear seismic location problem. In this work, we utilize differential evolution, which is a fast and robust global optimization method a...
Article
Full-text available
In microseismic monitoring, the temporal and spatial distribution of the positions of rock failures is used to image and analyze subsurface fractures. Therefore, source location is the most fundamental and most important step in microseismic data processing. In this paper, the research developments of microseismic location methods are introduced, e...
Article
Full-text available
Waveform-based seismic location methods can reliably and automatically image weak seismic sources, such as microseismic events and microtremors. Besides the classical diffraction stacking operator which is based on the one-way traveltime, correlation-based imaging methods are another subcategory of waveform-based methods using differential travelti...
Poster
Full-text available
Compared with traditional diffraction stacking, cross-correlation stacking can extract more redundancy in the data and suppress noise better, since it delays and stacks correlation waveforms of pair-wise receivers. In this work, we propose to double the correlation process of relative-correlation stacking, which is based on the differential travelt...
Conference Paper
Full-text available
Migration-based seismic location methods can reliably and automatically image weak seismic sources with low signal-to-noise ratios, such as microseisms and microtremors. Compared with traditional diffraction stacking, cross-correlation stacking can extract more redundancy in the data and suppress noise better, since it delays and stacks cross-corre...
Conference Paper
Full-text available
The efficiency of location methods is crucial for real-time microseismic monitoring. Migration-based methods can detect and locate very weak microseismic events, but they generally require more processing time and memory space than traveltime inversion. We propose to improve the efficiency of microseismic imaging methods with the particle swarm opt...
Conference Paper
Migration-based methods play an important role in microseismic source location, especially for surface monitoring with a large number of receivers. We compare three migration-based microseismic source location methods, namely, diffraction stacking, semblance-weighted stacking and cross-correlation stacking. The numerical results demonstrate the fea...
Conference Paper
Full-text available
Microseismic monitoring has been a key technology in the exploitation of unconventional reservoirs. Numerical simulation of various types of microseismic sources is the foundation for source location and source mechanism inversion. In this paper, equations of equivalent body forces with stress components and particle velocity components are derived...
Article
Full-text available
Combining a relative location method and seismic interferometric imaging, a relative elastic interferometric imaging method for microseismic source location is proposed. In the method, the information of a known event (the main event) is fully used to improve the location precision of the unknown events (the target events). First, the principles of...
Conference Paper
Source location is critical for utilizing the technology of microseismic monitoring. Combining a seismic interferometric imaging and a relative location method, the relative interferometric imaging method for microseismic source location is proposed in this work. A 3D horizontally layered velocity model and the finite difference method are used to...
Article
Full-text available
Knowledge of the locations of seismic sources is critical for microseismic monitoring. Time-window-based elastic wave interferometric imaging and weighted-elastic-wave (WEW) interferometric imaging are proposed and used to locate modeled microseismic sources. The proposed method improves the precision and eliminates artifacts in location profiles....
Patent
The invention relates to a microseismic interferometric imaging method. The method includes following steps: discretizing an underground model into grid points with a certain size, arranging n receivers in the underground model; establishing a velocity model, calculating the traveltime of first arrivals between each grid point and each receiver acc...

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Projects

Projects (3)
Project
Data stacking or beamforming has been routinely employed since its advent over 50 years ago and still remains one of the most robust and trusted processing steps in seismology. Due to the spatially limited extent of traditional receiver arrays, in earthquake studies beamforming only honors the slope of emerging wavefronts, whereas active-source seismology commonly deals with back-scattered waves and shallow structures where wavefront curvature is not negligible anymore. We investigate the obvious potential for unification of active and passive-source methodologies to arrive at improved scale-spanning applications in both fields.
Archived project
In this project, we propose to improve the efficiency of microseismic imaging methods with global optimization algorithms, e.g. particle swarm optimization (PSO), differential evolution (DE), neighbourhood algorithm (NA), which are stochastic and derivative-free global optimization algorithms that can rapidly converge toward the optimum. The performance of different global optimization algorithms will be tested and anlyzed. Moreover, the characteristics of different imaging operators can be exposed by analyzing their performance with the global optimization algorithm.
Archived project
Besides the diffraction stacking operator which is based on the one-way traveltime, correlation-based imaging methods are another subcategory of waveform-based location methods using differential traveltime. In this project, we review and compare these correlation-based methods by analyzing their imaging operators, characteristics of imaging resolution, and level of redundancy, etc. Synthetic and field data examples will be given to show their performance and feasibility in locating weak seismic events.