Realistic Fracture Research Articles

Least-squares interferometric migration of microseismic source location with a deblurring filter

Microseismic source locations play an important role in monitoring hydraulic fracturing in unconventional oil and gas exploration. Waveform-based source location methods can reliably and automatically image source locations without phase identification. A widely used and representative waveform-based method is interferometric migration (IM), which can eliminate the excitation-time term and image the source location in space by using correlograms of pairwise receivers. IM can avoid the trade-off between the inversions of excitation time and source location, but provides low-resolution source location images with strong migration artifacts. To improve the spatial resolution, we first developed a least-squares interferometric migration (LSIM). LSIM iteratively minimizes the correlogram residuals using the conjugate-gradient (CG) method. It provides a significant improvement in spatial resolution compared with conventional IM but requires a large number of iterations and high computational costs. To overcome this drawback, we develop an efficient least-squares interferometric migration with a deblurring filter (DLSIM) for high-resolution microseismic source locations. We introduce the Hessian matrix into the microseismic source location problem and approximate the inverse Hessian with a relatively inexpensive deblurring filter. The deblurring filter is applied to the updated gradient matrix in the CG algorithm. It could significantly accelerate the convergence rate of the least-squares inversion and meanwhile, provide a high spatial resolution. We use synthetic and real hydraulic fracturing data to demonstrate the robustness and effectiveness of DLSIM. Data noise, velocity error, and wavelet error are considered in the synthetic tests to simulate actual situations. The inverted results find that DLSIM achieves high-resolution source location images after 5–10 iterations that are equivalent to those of LSIM after approximately 50 iterations. Therefore, DLSIM can dramatically reduce the computational cost owing to its fewer number of iterations compared with LSIM.

Experimental–numerical studies of failure behavior of PLC optical splitters under uniaxial tensile loading

This work presents an experimental and numerical study of the failure behavior of planar lightwave circuit (PLC) optical splitters under uniaxial tensile loading. Based on the experimental results, the specific fracture position, ultimate failure load (Pm), failure mode and load-displacement behavior of the PLC optical splitter under uniaxial tensile loading were determined. In order to numerically simulate the real fracture behavior and stress distribution of adhesively bonded joints, a three-dimensional (3-D) explicit finite element analysis method based on material constitutive and tiebreak contact algorithm was proposed, which treats cohesive failure and adhesive/interfacial failure separately. The Pm predicted by the numerical simulation agrees well with the experimentally obtained Pm with a relative error of ∼4.3%, and the predicted failure mode is also similar to the experimentally observed mixed failure mode, which proves the accuracy and rationality of the adopted finite element method and model. This study can provide useful references for the reliability design and optimization of PLC optical splitters.

3D reconstruction of proximal femoral fracture from biplanar radiographs with fractural representative learning

A femoral fracture is a severe injury occurring in traumatic and pathologic causes. Diagnosis and Preoperative planning are indispensable procedures relying on preoperative radiographs such as X-ray and CT images. Nevertheless, CT imaging has a higher cost, radiation dose, and longer acquisition time than X-ray imaging. Thus, the fracture 3D reconstruction from X-ray images had been needed and remains a challenging problem, as well as a lack of dataset. This paper proposes a 3D proximal femoral fracture reconstruction from biplanar radiographs to improve the 3D visualization of bone fragments during preoperative planning. A novel Fracture Reconstruction Network (FracReconNet) is proposed to retrieve the femoral bone shape with fracture details, including the 3D Reconstruction Network (3DReconNet), novel Auxiliary class (AC), and Fractural augmentation (FA). The 3D reconstruction network applies a deep learning-based, fully Convolutional Network with Feature Pyramid Network architecture. Specifically, the auxiliary class is proposed, which refers to fracture representation. It encourages network learning to reconstruct the fracture. Since the samples are scarce to acquire, the fractural augmentation is invented to enlarge the fracture training samples and improve reconstruction accuracy. The evaluation of FracReconNet achieved a mIoU of 0.851 and mASSD of 0.906 mm. The proposed FracReconNet’s results show fracture detail similar to the real fracture, while the 3DReconNet cannot offer.

Channel connection and stimulated reservoir volume estimation derived by the timing, location, and focal mechanism of microseismic events

Understanding and modeling channels of high-pressure liquids during hydraulic fracturing and stimulated reservoir volume (SRV) estimation are critical for the evaluation of the fracturing effect and the prediction of oil and gas production in unconventional (low permeability and porosity) reservoirs. In this study, we developed a “focal mechanism-to-event” channel connection criterion based on the timing, location, and focal mechanism of microseismic events, enabling the channel to be perpendicular or parallel to the fracturing plane and more in line with the mechanical properties of rock rupture. We first evaluated the two endpoints of all channels as a set of spatial points, followed by the application of the alpha-shape method to detect the concave hull shape boundary formed by the spatial points. Finally, we calculated the SRV by combining the shapes of the concave hull and Delaunay triangulation. In the experimental simulation, we found that this method could effectively calculate the hull volume, and the detected concave hull included all microseismic events and channels. Ultimately, we applied the channel connection criterion and SRV estimation method to a stage of 3.18 h real fracturing data containing 216 microseismic events. The final calculation revealed a total of 410 connection channels and 4.3154 × 105 m3 SRV, which is more consistent with the expected than the “event-to-event” or “event-to-channel” connection criteria and bin or convex hull SRV calculation methods.

Study The Effect of Proppant Concentration of Screen-Out Phenomena While Hydraulic Fracture Job

screen out is a blocking of the fracture path caused by bridging the path or accumulation of the proppant inside the fracture, clumping or lodging of the (solid particles) proppant across the hydraulic fracture width that causes to restrict formation fluid to flow into the hydraulically fractured formation. To avoid the screen out happening needing to save fracturing fluids, hydraulic horsepower. Conditions that leading to screen out during the hydraulic fracturing job in a well, such as, the ratio between the fracture widths to particle diameter that called (β), proppant concentration,  and wall roughness. The effects of these factors are investigated experimentally in the present work by building an apparatus that meet the shape of the real hydraulic fracture. The plugging time were measured and monitored through glass windows on both sides of the apparatus to follow the behavior of the proppant inside the fracture during the flow of the fracturing fluid or when the proppant plugs the fracture. To study the effect of the fracture wall roughness on the screen out phenomena, apparatus was build to get two different fracture shapes, to meet the real fracture wall in reality. Through the relation between the different proppant concentration and the plugging time, one can indicate on the graph the plugging region and non plugging region for different values of β, proppant concentration and fracture shape, in order to avoid the screen out. During designing the hydraulic fracture, the values of β were very important factor that can lead to screen out, through the results found that when β=1, the screen out happened very fast even at low proppant concentration, but for β=2, 3 and 4 the screen out depends on the proppant concentration and fracture shape. For β=5 it was found that, there is no screen out occurring for wide range of proppant concentration. The effect of hydraulic fracture wall roughness is important because it effect the speed of the suspension when passing through the fracture.

Ascent rates of 3-D fractures driven by a finite batch of buoyant fluid

Propagation of fluid-filled fractures by fluid buoyancy is important in a variety of settings, from magmatic dykes and veins to water-filled crevasses in glaciers. Industrial hydro-fracturing utilises fluid-driven fractures to increase the permeability of rock formations, but few studies have quantified the effect of buoyancy on fracture pathways in this context. Analytical approximations for the buoyant ascent rate facilitate observation-based inference of buoyant effects in natural and engineered systems. Such analysis exists for two-dimensional fractures, but real fractures are three-dimensional (3-D). Here we present novel analysis to predict the buoyant ascent speed of 3-D fractures containing a fixed-volume batch of fluid. We provide two estimates of the ascent rate: an upper limit applicable at early time, and an asymptotic estimate (proportional to$t^{-2/3}$) describing how the speed decays at late time. We infer and verify these predictions by comparison with numerical experiments across a range of scales and analogue experiments on liquid oil in solid gelatine. We find the ascent speed is a function of the fluid volume, density, viscosity and the elastic parameters of the host medium. Our approximate solutions predict the ascent rate of fluid-driven fractures across a broad parameter space, including cases of water injection in shale and magmatic dykes. Our results demonstrate that in the absence of barriers or fluid loss, both dykes and industrial hydro-fractures can ascend by buoyancy over a kilometre within a day. We infer that barriers and fluid loss must cause the arrest of ascending fractures in industrial settings.

Elastic and strength properties of statistical volume elements: Determination of isotropic and homogeneous size limits

In this paper, a method is presented to describe the statistical behavior of mesoscale material property fields, which are useful in macroscopic fracture simulation. The use of representative volume element-based properties can result in unsatisfactory fracture patterns because this approach eliminates random variations. In contrast, statistical volume elements can approximate random and inhomogeneous material properties. We compare two material property convergence metrics based on 1) vanishing variations of a property and 2) the convergence of property mean value versus volume element size. We examine the trends with which the properties of a two-phase composite tend toward homogeneous and isotropic limits. Compared to fracture properties, elastic properties reach their homogeneous and isotropic limit at smaller sizes. Accordingly, a volume element size can be chosen such that only the apparent fracture strength remains random and inhomogeneous. This reduces the computational cost and has proven useful in capturing realistic fracture results. In addition, the geometry of the mesoscale partitioning scheme has an important effect on homogenized properties. The intersection of straight edges with inclusions results in nonphysical size effects, increases anisotropy of properties, and results in 30 to 60 times larger representative volume elements compared to a partitioning scheme based on Voronoi homogenization.

Influence of Fracture Geometric Characteristics on Fractured Rock Slope Stability

Analysis of the stability of slopes in fractured rock masses is not trivial and is fraught with uncertainty and risk. A DFN-DEC model (Discrete Fracture Network-Distinct Element Code) based on the MATLAB platform is developed to evaluate the stability of rock slopes with random fractures. Then, the influences of mean values of geometric characteristics (i.e., the trace length T, the dip D, and the spacing S) for both the horizontal (denoted with 1) and inclined (denoted with 2) fractures on the mean slope stability are investigated. The results indicate that the proposed DFN-DEC model based on the MATLAB platform is adequate, robust, and can generate more realistic fracture networks. By means of probabilistic analysis (i.e., Monte Carlo simulation), we can obtain a more accurate stability assessment result of fractured rock slopes. In addition, it is found that the μFs (the mean of Fs) of slopes decreases with the increase in μT1, μT2 (the mean trace length of horizontal and inclined fractures, respectively) and μD1 (the mean dip of horizontal fractures), and increases gradually with the increase in μD2 (the mean dip of inclined fractures), μS1 and μS2 (the mean spacing of horizontal and inclined fractures, respectively). Furthermore, the geometric characteristics related to inclined fractures have a much greater influence on μFS than that related to horizontal fractures. This study can be well applied in engineering practice, e.g., preliminary evaluation of the slope stability according to the statistics of fracture geometric characteristics.

Impact of fracture set scales and aperture enlargement due to karstic dissolution on the fluid flow behavior of carbonate reservoirs: A workflow to include sub-seismic fractures in 3D simulation models

Carbonate reservoirs might contain a large number of critical heterogeneities, such as fractures and karstic features, although some the existing heterogeneities cannot be identified due to the lack of seismic resolution. Our main objective is to evaluate which fracture scales need to be included in the fluid flow simulation models and, in particular, how to model subseismic fractures. We also consider the presence of enlarged fractures in the reservoir models due to karstic dissolution. The fracture network used to compose the simulation models is based on the real karstified fracture sets of the Soledade outcrop, Jandaíra Formation (Potiguar Basin, Brazil). This formation is a large and well-preserved karstified carbonate platform of the Turonian-Campanian age related to the South Atlantic opening. Our work is divided into three phases: in Phase 0, we show how to upscale the fracture network of the Soledade outcrop to in-situ deep conditions. As a result, a semi-synthetic simulation model is composed from the Soledade Outcrop data and of a Brazilian Pre-Salt carbonate reservoir. In Phase 1, we evaluated the impact of the fracture scales and fracture enlargement due to karstic dissolution on the fluid flow behavior of the semi-synthetic reservoir. Finally, in Phase 2, we propose and validate a fluid flow simulation workflow allowing to estimate a statistically equivalent network of subseismic fractures, which might be used on multiple data assimilation methods or in risk analysis of green fields. Results from Phase 1 evidence that subseismic fractures can significantly impact the fluid flow behavior, depending on the producing well location in relation to the fracture network and on the presence of enlarged fractures due to karstic dissolution. On the other hand, the Phase 2 results provide the oil and gas industry with a workflow to better characterize sub-seismic fractures in fluid flow simulation models.

Wavelet Entropy-Based Method for Migration Imaging of Hidden Microcracks by Using the Optimal Wave Velocity

Exploring the shape and direction of hidden cracks in a tunnel lining structure is one of the main objectives of ground penetrating radar (GPR) map interpretation. The most important factor that restricts the migration imaging of hidden cracks is the propagation velocity of electromagnetic waves. Determining the optimal electromagnetic wave velocity is the key to truthfully restoring the actual shape of hidden cracks. To study the GPR characteristic response signals of hidden cracks, forward simulation and model experiments of different cracks were performed. Subsequently, a method to determine the optimal electromagnetic wave velocity based on the wavelet entropy theory was proposed, and the frequency wavenumber domain migration (F-K) and Kirchhoff integral migration imaging method were combined. Horizontal, S-type, and inclined hidden fractures were examined by migration imaging. The results show that the radar characteristic response images of different cracks can be simulated forward by using the finite difference time domain method to write the fracture model instruction. Based on the wavelet entropy theory, the error range between the estimated value and true value was controlled within 4%. Taking the optimal electromagnetic wave velocity as the velocity parameter of the conventional migration method can make the migration more effective and suppress the interference of echo signals so that the diffraction wave converges, and the energy is more concentrated; thus, the real fracture morphology can be restored to the greatest extent. The research results can provide technical support for the fine detection of hidden quality defects in tunnel lining structures by GPR mapping.

Using Machine Learning to Predict Multiphase Flow through Complex Fractures

Multiphase flow properties of fractures are important in engineering applications such as hydraulic fracturing, evaluating the sealing capacity of caprocks, and the productivity of hydrocarbon-bearing tight rocks. Due to the computational requirements of high fidelity simulations, investigations of flow and transport through fractures typically rely on simplified assumptions applied to large fracture networks. These simplifications ignore the effect of pore-scale capillary phenomena and 3D realistic fracture morphology (for instance, tortuosity, contact points, and crevasses) that lead to macro-scale effective transport properties. The effect of these properties can be studied through lattice Boltzmann simulations, but they require high performance computing clusters and are generally limited in their domain size. In this work, we develop a technique to represent 3D fracture geometries and fluid distributions in 2D without losing any information. Using this innovative approach, we present a specialized machine learning model which only requires a few simulations for training but still accurately predicts fluid flow through 3D fractures. We demonstrate our technique using simulations of a water filled fracture being displaced by supercritical CO2. By generating highly efficient simulations of micro-scale multiphase flow in fractures, we hope to investigate a wide range of fracture types and generalize our method to be incorporated into larger discrete fracture network simulations.

Assessment of nonlinear flow behaviors through real rough rock fractures during shearing

Assessment of nonlinear flow behaviors through real rough rock fractures during shearing

Phase-field finite deformation fracture with an effective energy for regularized crack face contact

Phase-field models are a leading approach for realistic fracture problems. They treat the crack as a second phase and use gradient terms to smear out the crack faces, enabling the use of standard numerical methods for simulations. This regularization causes cracks to occupy a finite volume in the reference, and leads to the inability to appropriately model the closing or contacting -- without healing -- of crack faces. Specifically, the classical idealized crack face tractions are that the shear component is zero, and that the normal component is zero when the crack opens and identical to the intact material when the crack closes. Phase-field fracture models do not replicate this behavior. This work addresses this shortcoming by introducing an effective crack energy density that endows the regularized (finite volume) phase-field crack with the effective properties of an idealized sharp crack. The approach is based on applying the QR (upper triangular) decomposition of the deformation gradient tensor in the basis of the crack, enabling a transparent identification of the crack deformation modes. By then relaxing over those modes that do not cost energy, an effective energy is obtained that has the intact response when the crack faces close and zero energy when the crack faces are open. A highlight of this approach is that it lies completely in the setting of finite deformation, enabling potential application to soft materials and other settings with large deformation or rotations. The model is applied to numerically study representative complex loadings, including (1) cyclic loading on a cavity in a soft solid that shows the growth and closing of cracks in complex stress states; and (2) cyclic shear that shows a complex pattern of crack branching driven by the closure of cracks.

Study on proppant embedment in rough fracture surface based on three dimension laser scanning

In formation, fracture surfaces are rough and proppant embedment is complex. However, when conducting proppant embedding experiments, most researchers assume a smooth fracture surface, which does not accurately reflect the real fracture. As a result, the rough fracture surface is scanned by three dimension (3D) laser to reconstruct the rough fracture based on the point data in this paper, which established a “proppant - rough fracture” contact model based on finite element theory, analyzed the influence (the closure stress and young's modulus of proppant, proppant size, the elastic modulus of proppant and rock) of embedment depth in the rough fracture. Numerical simulation results show that the embedment depth of the proppant increases with the increase of closure stress. The embedment depth of proppant on rough fracture surface increases with the increase of proppant elastic modulus but decreases with the increase of rock's elastic modulus. The embedment depth of the proppant in the rough fracture is smaller than that in a smooth plate under the same closure stress. To ensure the consistency, repeatability, and accuracy of the rough fracture surface, it was analyzed using reverse reconstruction. This study can be used as a simple method to investigate the rule of proppant embedment in rough fracture surfaces to provide a reference and basis for hydraulic fracturing in the oilfield.

Experimental study on the effect of fracture surface morphology on plugging zone strength based on 3D printing

In this paper, laser scanning combined with stereo-lithography appearance (SLA) is used to study the influence of fracture surface morphology on the plugging effect of laboratory fracture plugs, in order to incorporate the fracture surface fluctuation into the design of plugging formula for fractured formations. To our knowledge, this is the first study on the maximum plugging pressure considering the real fracture surface fluctuation using 3D printing technology. The experimental results show a significant positive correlation between the maximum plugging pressure of the average bulge height, the average inclination angle of fracture surface, and the JRC coefficient. With the increase of these characteristic parameters of fracture surfaces, the maximum plugging pressure also increases. Observation of the fracture plugging zone after the experiment indicates that the front edge of the fracture plugging zone is the same as the violent local fluctuations in the height of the fracture surface. The present research suggests that the fluctuation of fracture surface provides many inclined supporting surfaces and strengthens the supporting effect of fracture surface on loss control materials (LCM). The dislocation of the “step-like” flow channel caused by the sudden change of the fracture can induce local single-particle straining and local multi-particle bridging in the flow channel, which significantly improves the maximum plugging pressure of the fracture plugging zone. According to the fracture surface fluctuation difference, the plugging effect of the same formula for fractures with the same opening is different, so it is necessary to improve the plugging formula design in combination with a geological engineering background. This understanding is of great significance for the analysis of fracture plugging mechanisms and optimized design of plugging formulas for fractured reservoirs. It will contribute to the high-efficiency and environment-friendly exploitation of energy and resources.

Experimental Study on the Effect of Bedding on the Fracture Process Zone of Shale

The conventional fracture in shale hydraulic fracturing belongs to the type-I fracture, and the size of the fracture process zone (FPZ) is an important index to measure the fracability of rock mass. This index is also one of the feasible entry points to study the complexity of the fracture network. In order to visually observe the type-I FPZ at the tip of shale fractures, and to study the relationship between the mechanical properties, the shape and size of the FPZ, and the bedding structure, Notched Semi-Circular Bend (NSCB) tests were conducted with three typical fracture direction-bedding orientations (splitter, arrester, divider). The digital image correlation (DIC) method was used to realize the intuitive observation of the real fracture process and the FPZ near the fracture tip. The test found that the FPZ of shale is narrow and long as a whole and is “flame-like”. The height-to-length ratio of the FPZ at the fracture tip determines whether bending and deflection happen between the new fracture and the prefabricated cracks when the fracture occurs. Most of the specimens often appear in the FPZ with a beaded high shear strain zone before the fracture, which is caused by the oblique communication of micro-cracks in the FPZ before the fracture. The appearance of a beaded zone of high shear strain indicates that macroscopic fracture is imminent. The research results can be used for the design of disaster early warning and prevention programs.

Experimental investigation on proppant transport and distribution characteristics in coal hydraulic fractures under true triaxial stresses

Fracturing is one of the key technologies for unconventional oil and gas production. However, the closure stress will cause the hydraulic fractures to close, and proppant is often injected into the fracture to maintain the effective conductivity of the fractures for a long time. The proppant distribution in the fractures is one of the key factors affecting the efficient exploitation of unconventional natural gas. However, there are few studies on the proppant transport and distribution characteristics in the real hydraulic fractures. A self-developed high-pressure sand injection triaxial hydraulic fracturing experimental system was used to study the proppant migration and distribution in hydraulic fractures. The results show that the proppant migration process mainly includes four stages: water filling stage, fracture reopening stage, proppant transport stage, and pressure relief stage. The basic characteristics of proppant transport in horizontal fractures is mainly along slope gradient transport or dispersion, and reverse slope gradient or low valley deposition. The sedimentary areas mainly include peak climbing deposition, ring peak deposition, and convection-diffusion deposition. The surface roughness of horizontal fractures is one of the key factors affecting the proppant transport and distribution. The fracture inlet roughness determines the proppant transport direction, and the overall roughness of the fracture surface determines the proppant distribution form. The proppant deposition is the most in the open hole parallel area, followed by the sealed hole parallel area in vertical fractures. The stress concentration at the hole bottom forms horizontal wing branch fractures, and a little proppant is deposited in the fractures. Generally, the stress required for proppant transport in horizontal fractures is smaller than that in vertical fractures. The findings of this study can help us better understand the migration and distribution of proppant in hydraulic fractures, and provide theoretical guidance for the efficient exploitation of unconventional natural gas.

Impact of fracture normal and shear stiffnesses on the scattering attenuation of P and S waves in a naturally fractured rock

In this paper, numerical simulations are conducted to study elastic wave transport, scattering, and attenuation in a naturally fractured rock associated with length-correlated fracture normal and shear stiffnesses. The model represents the pattern of a real fracture outcrop in an explicit fashion based on the discrete fracture network approach and computes the dynamical interaction between waves and fractures based on the displacement discontinuity method. A broad spectrum of geologically relevant fracture stiffness values are explored to analyse the impact of fracture normal and shear stiffness components on the wavefield evolution. It is observed that when the fracture normal and shear stiffnesses are both high, the wavefield is a propagative mode dominated by a forward ballistic transport. With the reduction of fracture normal and/or shear stiffnesses, the wavefield becomes diffusive characterised by the emergence and dominance of coda waves. If the fracture stiffnesses are very low, waves become trapped entering the so-called localisation regime associated with an absence of effective transport as well as a profound attenuation. Our results show that the scattering attenuation of S waves tends to be greater than that of P waves in the propagation and diffusion regimes, but becomes similar in the localisation regime. The research findings of this paper have important implications for understanding and predicting the seismic wave attenuation behaviour in naturally fractured rocks for various geophysical applications.

3D analysis of Rayleigh-type surface wave in fractured media: Insights into anisotropic characteristics

The propagation characteristics of Rayleigh waves on the surfaces of fracture-containing media have considerable theoretical and practical significance. Limitations are associated with using two-dimensional (2D) observations of Rayleigh waves to predict fracture features, because real fractures have a complex distribution inside media. Therefore, the three-dimensional (3D) propagation of Rayleigh waves in media with directional fractures is simulated in this study by combining the staggered-grid finite difference method with parallel computing. The wave velocity and amplitude of Rayleigh waves depend on the relative direction between fracture and wave path on the medium surface. That is, Rayleigh waves exhibit clearly anisotropic characteristics for a medium with directionally distributed fractures, where the degree of anisotropy is closely related to fracture parameters, such as the fracture density and fracture scale. Two new anisotropy parameters for Rayleigh waves are defined in this study: the anisotropy of the wave velocity and the anisotropy of attenuation (transmission coefficient). For a single fracture, the minor axis of the anisotropic quasi-semiellipse and the locations of discontinuities can indicate the normal direction of the fracture and the fracture distribution range, respectively. For multiple fractures, the major axis of the anisotropic quasi-semiellipse of the Rayleigh wave has almost the same direction as the main distribution of the fracture zone. This study provides theoretical support for the accurate prediction of complex fracture parameters inside media.

Vibration characteristics of rotor-bearing system with angular misalignment and cage fracture: Simulation and experiment

The rolling bearing misalignment may lead to fracture failure of the cage. However, the research on the vibration response of the rotor system caused by bearing misalignment and cage fracture has not attracted enough attention. In this paper, the vibration characteristics of cage fracture fault are studied from two aspects of simulation and experiment. Firstly, a five-degree of freedom nonlinear bearing force model with the bearing misalignment and cage fracture fault is given. Secondly, the bearing restoring force model is introduced into the rotor finite element model. Then, the dynamic model of the deep groove ball bearing-rotor system is established. The effects of key parameters such as cage fracture degree, radial load, and bearing clearance on the vibration characteristics of the system are simulated and analyzed. Thirdly, the bearing test pieces with real cage fatigue fracture fault are obtained by carrying out the bearing life cycle test. On this basis, the vibration signals of bearing with cage fracture under different loads are collected.The simulation and test results show that the system amplitude increases when cage fracture occurs. The obvious impact vibration characteristics appear in the time domain waveform. The vibration energy gradually concentrates to low-frequency vibration. The frequency components related to cage frequency, such as nfc and nfr ± mfc can be more obviously observed in the envelope spectrum. The results can provide a useful reference for the identification and diagnosis of rolling bearing misalignment and cage fracture.