Fault slippage and its permeability evolution during supercritical CO2 fracturing in layered formation

International audienceUnderstanding the hydromechanical responses of faults during supercritical CO2 fracturing is important for reservoir management and the design of energy extraction systems. As small faults are widespread in Chang 7 member of the Yanchang Formation, Ordos Basin, China, supercritical CO2 fracturing operation has the potential to reactive these undetected small faults and leads to unfavorable fracking fluid migrate. In this work, we examined the role of fault slippage and permeability evolution along a small fault connecting the pay zone and the confining formation during the whole process of fracturing and production. A coupled hydromechanical model conceptualized from actual engineering results was introduced to address the main concerns of this work, including, (1) whether the existence of a undetected small fault would effectively constrain the hydraulic fracture height evolution, (2) what the magnitude of the induced microseismic events would be and (3) whether the permeability change along the fault plane would affect the vertical conductivity of the confining formation and thus increase the risk for the fracturing fluid to leak. Our results have shown that the initial hydrofracture formed at the perforation and propagated upward, once it merged with the fault surface, the existence of an undetected small fault would effectively constrain the hydraulic fracture height evolution. As fracturing continued, further slippage spread from the permeability increase zone of high permeability to shallower levels, and the extent of this zone was dependent on the magnitude of the fault slippage. At the end of extraction, the slip velocity decreases gradually to zero and the fault slippage finally reaches stabilization. In general, undetected small faults in targeted reservoir may not be the source of large earthquakes. The induced microseismic events could be considered as the sources of acoustic emission events detected while monitoring the fracturing fluid front. Due to the limited fault slippage and lower initial permeability, the CO2 fracturing operation near undetected small faults could not conduct preferential pathway for upward CO2 leakage or contaminate overlying shallower potable aquifers

Case report: Novel compound heterozygous variants in the PANK2 gene in a Chinese patient diagnosed with ASD and ADHD

The PANK2 gene, which encodes mitochondrial pantothenate kinase 2 protein, is the disease-causing gene for pantothenate kinase-associated neurodegeneration (PKAN). We report a case of atypical PKAN with autism-like symptoms presenting with speech difficulties, psychiatric symptoms, and mild developmental retardation. Magnetic resonance imaging (MRI) of the brain showed the typical “eye-of-the-tiger” sign. Whole-exon sequencing revealed PANK2 p.Ile501Asn/p.Thr498Ser compound heterozygous variants. Our study highlights the phenotypic heterogeneity of PKAN, which can be confused with autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD) and requires careful clinical identification

ConTex-Human: Free-View Rendering of Human from a Single Image with Texture-Consistent Synthesis

In this work, we propose a method to address the challenge of rendering a 3D human from a single image in a free-view manner. Some existing approaches could achieve this by using generalizable pixel-aligned implicit fields to reconstruct a textured mesh of a human or by employing a 2D diffusion model as guidance with the Score Distillation Sampling (SDS) method, to lift the 2D image into 3D space. However, a generalizable implicit field often results in an over-smooth texture field, while the SDS method tends to lead to a texture-inconsistent novel view with the input image. In this paper, we introduce a texture-consistent back view synthesis module that could transfer the reference image content to the back view through depth and text-guided attention injection. Moreover, to alleviate the color distortion that occurs in the side region, we propose a visibility-aware patch consistency regularization for texture mapping and refinement combined with the synthesized back view texture. With the above techniques, we could achieve high-fidelity and texture-consistent human rendering from a single image. Experiments conducted on both real and synthetic data demonstrate the effectiveness of our method and show that our approach outperforms previous baseline methods.Comment: see project page: https://gaoxiangjun.github.io/contex_human

Correlation between intercalated magnetic layers and superconductivity in pressurized EuFe2(As0.81P0.19)2

We report comprehensive high pressure studies on correlation between intercalated magnetic layers and superconductivity in EuFe2(As0.81P0.19)2 single crystal through in-situ high pressure resistance, specific heat, X-ray diffraction and X-ray absorption measurements. We find that an unconfirmed magnetic order of the intercalated layers coexists with superconductivity in a narrow pressure range 0-0.5GPa, and then it converts to a ferromagnetic (FM) order at pressure above 0.5 GPa, where its superconductivity is absent. The obtained temperature-pressure phase diagram clearly demonstrates that the unconfirmed magnetic order can emerge from the superconducting state. In stark contrast, the superconductivity cannot develop from the FM state that is evolved from the unconfirmed magnetic state. High pressure X-ray absorption (XAS) measurements reveal that the pressure-induced enhancement of Eu's mean valence plays an important role in suppressing the superconductivity and tuning the transition from the unconfirmed magnetic state to a FM state. The unusual interplay among valence state of Eu ions, magnetism and superconductivity under pressure may shed new light on understanding the role of the intercalated magnetic layers in Fe-based superconductors

Accelerated Transport through Sliding Dynamics of Rodlike Particles in Macromolecular Networks

Transport of rodlike particles in macromolecular networks is critical for many important biological processes and technological applications. Here, we report that speeding-up dynamics occurs once the rod length L reaches around integral multiple of the network mesh size ax. We find that such a fast diffusion follows the sliding dynamics and demonstrate it to be anomalous yet Brownian. The good agreement between theoretical analysis and simulations corroborates that sliding dynamics is an intermediate regime between hopping and Brownian dynamics, and suggests a mechanistic interpretation based on the rod-length dependent entropic free energy barrier. These theoretical findings are captured by the experimental observations of rods in synthetic networks, and bring new insight into the physics of the transport dynamics in confined media of networks

Robust Super-Resolution Imaging Based on a Ring Core Fiber with Orbital Angular Momentum

Single fiber imaging technology offers unique insights for research and inspection in difficult to reach and narrow spaces. In particular, ultra-compact multimode fiber (MMF) imaging, has received increasing interest over the past decade. However, MMF imaging will be seriously distorted when subjected to dynamic perturbations due to time-varying mode coupling, and the imaging of space objects via Gaussian beam will be relatively degraded at the edge due to insufficient contrast. Here, a robust super-resolution imaging method based on a ring core fiber (RCF) with orbital angular momentum (OAM) has been proposed and experimentally demonstrated. The OAM modes propagating in the RCF form a series of weakly-coupled mode groups, making our imaging system robust to external perturbations. In addition, a spiral phase plate is used as a vortex filter to produce OAM for edge enhancement, thus improving the image resolution. Furthermore, a few-shot U-Transformer neural network is proposed to enhance the resilience of the developed RCF-OAM imaging system against environmental perturbations. Finally, the developed RCF-OAM imaging system achieves biological image transmission, demonstrating the practicality of our scheme. This pioneering RCF OAM imaging system may have broad applications, potentially revolutionising fields such as biological imaging and industrial non-destructive testing