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Science China(Information Sciences) 2024年第1期67卷 203-220页

作者： Jie WANG Jiamin LI Pengcheng ZHU Dongming WANG Hongbiao ZHANG Yue HAO Bin SHENG National Mobile Communications research Laboratory Southeast University 2. Purple Mountain Laboratories China Mobile research institute

Network-assisted full-duplex(NAFD) cell-free distributed massive multiple-input multipleoutput(MIMO) systems enable uplink(UL) and downlink(DL) communications within the same timefrequency resources,which potentially reduce latency by avoiding the overhead of switching UL/DL ***,how to choose UL/DL modes remains an important factor affecting system *** the dramatic increase in the number of users and access points(APs),massive access brings significant overhead in the mode ***,the different quality of service(QoS) among users also makes the effective utilization of resources *** one of the most promising technologies in sixth-generation(6G),network slicing enables the adaptive configuration of limited UL/DL resources through the resource isolation assisted NAFD ***,we propose a slicing capacity-centered *** this scheme,APs are motivated by slicing requirements and associated slices to form different *** mode selection and resource allocation are performed within each subsystem to reduce overhead and improve resource *** implement this scheme efficiently,a double-layer deep reinforcement learning(DRL)mechanism is used to realize the joint optimization of mode selection and resource *** results show that the slicing capacity-centered scheme can effectively improve resource utilization and reduce overhead.

关键词： network-assisted full-duplex network slicing mode selection resource optimization deep reinforcement learning

Geochemistry and depositional environment of fuchsite quartzites from Sargur Group,western Dharwar Craton,India

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Acta Geochimica 2024年第3期43卷 555-570页

作者： C.S.Sindhuja G.Harshitha C.Manikyamba K.S.V.Subramanyam CSIR(Council of Scientific and Industrial research)-National geophysical research institute(NGRI) Uppal RoadHyderabad 500007India

Meso-Neoarchean fuchsite quartzites are present in different stratigraphic positions of Dharwar Craton including the oldest(~3.3 Ga)Sargur Group of western Dharwar *** present study deals with the petro-graphic and geochemical characteristics of the fuchsite quartzites from the Ghattihosahalli belt to evaluate their genesis,depositional setting and the enigma involved in the ancient sedimentation *** major mineral assemblages include quartz,fuchsite,and feldspars along with accessory kyanite and *** geochemical com-positions are characterized by high SiO_(2.,Al_(2.O_(3),low MgO,CaO,strongly enriched Cr(132.–6899 ppm),Ba(1165–3653 ppm),Sr(46–2.0 ppm),V(107–868 ppm)and Zn(11–158 ppm)contents compared to the upper continental crust(UCC).The UCC normalized rare earth element(REE)patterns are characterized by depleted light REE[(La/Sm)UCC=0.33–0.95]compared to heavy REE[(Gd/Yb)_(UCC)=0.42.1.65]with conspicuous positive Eu-anomalies(Eu/Eu^(*)=1.35–18.2.)characteristic of hydrothermal solutions evidenced through the interlayered *** overall major and trace element systematics reflect a combined mafic-felsic provenance and suggest their deposition at a passive continental margin *** comprehensivefield,petrographic,and geo-chemical studies indicate that these quartzites are infiltrated by Cr-richfluids released during high-grade metamorphism of associated ultramafic *** Sargur and the subse-quent Dharwar orogeny amalgamated diverse lithounits from different tectonic settings,possibly leading to the release of Cr-richfluids and the formation of fuchsite quartzite during or after the *** sug-gest a pre-existing stable crust prior to the Sargur Group and the link between orogenic events and various mineral deposits in the Dharwar Craton.

关键词： Dharwar Craton Ghattihosahalli Fuchsite quartzite Provenance Depositional setting

Geochemistry and mineral chemistry of the armoor granitoids,eastern dharwar craton: implications for the redox conditions and tectono-magmatic environment

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Acta Geochimica 2024年第1期43卷 110-133页

作者： A.Ajay Kumar Ch.Ashok Department of Geology Osmania UniversityHyderabad 500007India CSIR-National geophysical research {2. UppalHyderabad 500007India

The mineralogical and geochemical characteristics of the K-rich granites from the Armoor granitic rocks in the northeastern portion of the Eastern Dharwar Craton(EDC) are *** order to understand its physicochemical conditions,the petrogenesis of the granitoid was explained from biotite chemistry and geochemical *** of mineral chemistry expose that compositionally,K-feldspar and plagioclase in Armoor granite rocks range from An0,Ab_(3-5.9),Or_(94-96.9) and An_(5-2.,-Ab71.9-94.9),Or_(0-1.5),*** mineral chemistry of biotite crystals exhibits composition that varies from primary to re-equilibrated primary *** biotites from the Armoor granites generally exhibit an I-type trend,with calc-alkaline parental magma in a subduction *** chemistry of granites displays magnetite(oxidized)series nature,which has oxygen fugacity(fO_(2.)=-15.1 to-16.7(log_(10) bar),under high oxidizing *** and pressure estimates for the crystallization of Armoor granites based on biotite composition are T=612.716 ℃ and 1.0-0.4 kbar,***,these rocks are metaluminous to slightly peraluminous and magnesian,with calc-alkaline potassiumrich *** the chondrite normalized REE diagram,the granites have positive europium anomalies;rich Sr/Y,(Dy/Yb)_(N) ratios and reduced Mg#,Rb/Sr,Rb,Sr indicate that the melting of earlier rocks,crystal accumulation and residual garnet source formed at high *** examined granites show that they are produced from the melting of crustal ***,the extensive analyses of the described Armoor granite suggest that they were produced by crust sources and developed under oxidizing conditions in subduction setting.

关键词： Armoor granites Oxygen fugacity Crystal accumulation Remelting Subduction

Geochemistry of volcanic glass from Mahanadi offshore region,eastern continental margin of India:Constraints on the contribution of latest Toba super-eruption

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Acta Oceanologica Sinica 2024年第2期43卷 111-119页

作者： Muralidhar Kocherla Durbar Ray Manavalan Satyanarayanan Hilda Joao Virsen Gaikwad PB Ramamurty CSIR-National institute of Oceanography Dona Paula 403004GoaIndia CSIR-National geophysical research {2. Uppal RoadHyderabad 500007India

The tephra layers in multiple sediment cores from the offshore region of the Mahanadi basin in the northern Bay of Bengal were investigated for possible volcanic sources. The glass shards from those tephra layers were studied for size distribution, texture, and elemental geochemistry to establish chronostratigraphic markers for regional and global Quaternary correlation. The textural features of fine-grained(silty) volcanic glasses suggest the distal source of these tephra deposits. Major element composition with elevated SiO_(2. contents ranging between75%–76% and dominance of K_(2.O(> 4.5%) over CaO(< 0.9%) suggest ashes have originated from siliceous rhyolitic melts, similar to the petrographic composition of tephra from the Toba volcano. The bulk trace element compositions of the same glass shards were comparable with those reported in the youngest Toba tephra reported elsewhere. Likewise, the LREE-dominated chondrite normalized REE profiles of tephra from the Mahanadi basin closely resemble the characteristic REE patterns in Toba ash from other parts of the Indian Ocean and thus confirmed the contribution of the youngest Toba super-eruption for this ash layers.

关键词： Mahanadi basin Bay of Bengal volcanic glass glass morphology glass-chemistry

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Petroleum Science 2024年第4期21卷 2383-2392页

作者： Li-Ming Zhao Cai-Ping Lu Yang Liu Chao-Chao Li School of Mines China University of Mining and Technology Henan institute of geophysical Space Information

The similarities and differences in inherent mechanism and characteristic frequency between the onedimensional(1D) poroelastic model and the layered White model were investigated. This investigation was conducted under the assumption that the rock was homogenous and isotropic at the mesoscopic scale. For the inherent mechanism, both models resulted from quasi-static flow in a slow P-wave diffusion mode, and the differences between them originated from saturated fluids and boundary conditions. On the other hand, for the characteristic frequencies of the models, the characteristic frequency of the 1D poroelastic model was first modified because the elastic constant and formula for calculating it were misused and then compared to that of the layered White model. Both of them moved towards higher frequencies with increasing permeability and decreasing viscosity and diffusion length. The differences between them were due to the diffusion length. The diffusion length for the 1D poroelastic model was determined by the sample length, whereas that for the layered White model was determined by the length of the representative elementary volume(REV). Subsequently, a numerical example was presented to demonstrate the similarities and differences between the models. Finally, published experimental data were interpreted using the 1D poroelastic model combined with the Cole-Cole *** prediction of the combined model was in good agreement with the experimental data, thereby validating the effectiveness of the 1D poroelastic model. Furthermore, the modified characteristic frequency in our study was much closer to the experimental data than the previous prediction, validating the effectiveness of our modification of the characteristic frequency of the 1D poroelastic model. The investigation provided insight into the internal relationship between wave-induced fluid flow(WIFF)models at macroscopic and mesoscopic scales and can aid in a better understanding of the elastic modulus d

关键词： 1D poroelastic model Layered White model Quasi-static flow Slow P-wave diffusion Characteristic frequency Diffusion length

A reweighted damped singular spectrum analysis method for robust seismic noise suppression

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Petroleum Science 2024年第3期21卷 1671-1682页

作者： Wei-Lin Huang Yan-Xin Zhou Yang Zhou Wei-Jie Liu Ji-Dong Li State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing2249China SINOPEC Petroleum Exploration and Production research institute Beijing102206China SINOPEC geophysical research {2. Nanjing211103jiangsuChina

(Multichannel)Singular spectrum analysis is considered as one of the most effective methods for seismic incoherent noise *** utilizes the low-rank feature of seismic signal and regards the noise suppression as a low-rank reconstruction ***,in some cases the seismic geophones receive some erratic disturbances and the amplitudes are dramatically larger than other *** presence of this kind of noise,called erratic noise,makes singular spectrum analysis(SSA)reconstruction unstable and has undesirable effects on the final *** robustify the low-rank reconstruction of seismic data by a reweighted damped SSA(RD-SSA)*** incorporates the damped SSA,an improved version of SSA,into a reweighted *** damping operator is used to weaken the artificial disturbance introduced by the low-rank projection of both erratic and random *** central idea of the RD-SSA method is to iteratively approximate the observed data with the quadratic norm for the first iteration and the Tukeys bisquare norm for the rest *** RD-SSA method can suppress seismic incoherent noise and keep the reconstruction process robust to the erratic *** feasibility of RD-SSA is validated via both synthetic and field data examples.

关键词： Singular spectrum analysis Damping operator Seismic erratic noise Seismic signal processing Robust low-rank reconstruction

A deep learning framework for suppressing prestack seismic random noise without noise-free labels

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Energy Geoscience 2024年第3期5卷 261-274页

作者： Han Wang Jie Zhang Petroleum Exploration and Production research institute SINOPECBeijing100083China geophysical research {2. School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefeiAnhui230026China

Random noise attenuation is significant in seismic data *** deep learning-based denoising methods have been widely developed and applied in recent *** practice,it is often time-consuming and laborious to obtain noise-free data for supervised ***,we propose a novel deep learning framework to denoise prestack seismic data without clean labels,which trains a high-resolution residual neural network(SRResnet)with noisy data for input and the same valid data with different noise for *** valid signals in noisy sample pairs are spatially correlated and random noise is spatially independent and unpredictable,the model can learn the features of valid data while suppressing random *** data targets are generated by a simple conventional method without fine-tuning *** initial estimates allow signal or noise leakage as the network does not require clean *** Monte Carlo strategy is applied to select training patches for increasing valid patches and expanding training *** learning is used to improve the generalization of real data *** synthetic and real data tests perform better than the commonly used state-of-the-art denoising methods.

关键词： Data processing Denoising Signal processing Seismics Deep learning

An adaptive finite-difference method for seismic traveltime modeling based on 3D eikonal equation

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Petroleum Science 2024年第1期21卷 195-205页

作者： Bao-Ping Qiao Qing-Qing Li Wei-Guang He Dan Zhao Qu-Bo Wu CNNC Beijing research institute of Uranium Geology Beijing 100029China National Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao 266580ShangdongChina SINOPEC geophysical research {2. Nanjing211103JiangsuChina

3D eikonal equation is a partial differential equation for the calculation of first-arrival traveltimes and has been widely applied in many scopes such as ray tracing,source localization,reflection migration,seismic monitoring and tomographic *** recent years,many advanced methods have been developed to solve the 3D eikonal equation in heterogeneous ***,there are still challenges for the stable and accurate calculation of first-arrival traveltimes in 3D strongly inhomogeneous *** this paper,we propose an adaptive finite-difference(AFD)method to numerically solve the 3D eikonal *** novel method makes full use of the advantages of different local operators characterizing different seismic wave types to calculate factors and traveltimes,and then the most accurate factor and traveltime are adaptively selected for the convergent updating based on the Fermat *** with global fast sweeping describing seismic waves propagating along eight directions in 3D media,our novel method can achieve the robust calculation of first-arrival traveltimes with high precision at grid points either near source point or far away from source point even in a velocity model with large and sharp *** numerical examples show the good performance of the AFD method,which will be beneficial to many scientific applications.

关键词： 3D eikonal equation Accurate traveltimes Global fast sweeping 3D inhomogeneous media Adaptive finite-difference method

Study of Seismic P Wave in Mesoscale Fracture-Induced Arbitrary Anisotropic Media

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Journal of Earth Science 2024年第2期35卷 717-721页

作者： Han Xiao Xinmin Shang Zhentao Wang Xiping Wang geophysical research {2. SINOPEC Shengli Oilfield CompanyShandong 257022China Working Station for Postdoctoral Scientific research Shengli OilfieldShandong 257000China

Mesoscale fracture controls the permeability of shale res ervoirs,it is one of the main research objectives of natural frac *** length of the mesoscale fracture is less than 1/4 of the seismic eigen wavelength and greater than 1%of the seis mic eigen wavelength,they cannot be identified in actual seis mic data and are usually displayed by the azimuthal anisotropy of seismic *** this paper,we propose a calculation process from fracture properties to seismic P-wave velocity and traveltime in anisotropic media induced by multiple sets of arbitrary occurring mesoscale *** on this process,the variations of the media’s Anisotropic(A-)parameters with fracture properties are ***,variation of P-wave NMO elliptical principle axis with the relative fracture density is studied according to the arbitrary anisotropic theory based on A-parameters.

关键词： seismic mesoscale shale

An improved deep dilated convolutional neural network for seismic facies interpretation

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Petroleum Science 2024年第3期21卷 1569-1583页

作者： Na-Xia Yang Guo-Fa Li Ting-Hui Li Dong-Feng Zhao Wei-Wei Gu State Key Laboratory of Petroleum Resources and Engineering CNPC Key Lab of Geophysical ExplorationChina University of Petroleum(Beijing)Beijing 102249China Dagang Branch Research InstituteBGPTianjin300280China

With the successful application and breakthrough of deep learning technology in image segmentation,there has been continuous development in the field of seismic facies interpretation using convolutional neural *** intelligent and automated methods significantly reduce manual labor,particularly in the laborious task of manually labeling seismic ***,the extensive demand for training data imposes limitations on their wider *** overcome this challenge,we adopt the UNet architecture as the foundational network structure for seismic facies classification,which has demonstrated effective segmentation results even with small-sample training ***,we integrate spatial pyramid pooling and dilated convolution modules into the network architecture to enhance the perception of spatial information across a broader *** seismic facies classification test on the public data from the F3 block verifies the superior performance of our proposed improved network structure in delineating seismic facies *** analysis against the traditional UNet model reveals that our method achieves more accurate predictive classification results,as evidenced by various evaluation metrics for image ***,the classification accuracy reaches an impressive 96%.Furthermore,the results of seismic facies classification in the seismic slice dimension provide further confirmation of the superior performance of our proposed method,which accurately defines the range of different seismic *** approach holds significant potential for analyzing geological patterns and extracting valuable depositional information.

关键词： Seismic facies interpretation Dilated convolution Spatial pyramid pooling Internal feature maps Compound loss function