英文摘要

Adepth-constraintmulti-targetpositioningacousticapproachinshallowwaters.LIUHuimin1,WANGZhenjie1,2,andZHAOShuang1.OilGeophysicalProspecting,2019,54(6):1181-1187.

A depth-constraint multi-target positioning acoustic approach in shallow waters is proposed in this paper using shipborne DGPS data and single-beam sounding data.Combined with the spatial interpolation method of regional natural critical points,a regional elevation model is built,and the transponder elevation interpolation is carried out for the horizontal position of IGG3 tolerance estimation solution.According to the symmetry observation and the smooth seabed topography in the working area,bending errors of acoustic line are further eliminated with an acoustic line bending segmented model in order to improve the planar positioning accuracy of multi-targets in shallow waters.Experimental results in the South China Sea show that the model built by the proposed approach is characterized by strong anti-gross-error capability and can effectively improve the positioning accuracy under the conditions of inaccurate sound velocity measurements and observation data with large gross errors.

Keywords: acoustic positioning,depth-constraint,single beam sounding,depth interpolation

1.School of Geosciences,China University of Petroleum (East China),Qingdao,Shandong 266580,China

2.Laboratory for Marine Mineral Resources,Qingdao National Laboratory for Marine Science and Technology,Qingdao,Shandong 266071,China

3DBlockmatchingseismicdatadenoisingbasedonCurveletnoiseestimation.SUNChengyu1,2,DIAOJuncai1,2,andLIWenjing3.OilGeophysicalProspecting,2019,54(6):1188-1194.

Conventional 3D block matching (BM3D) algorithms are used for seismic data denoising.However,some parameters such as filtering threshold are difficult to be determined because of the lack of prior noise information in the practical processing.In this paper,an improved BM3D denoising method based on the Curvelet noise estimation is developed for seismic data.First the noise variance of seismic data is estimated by the Curvelet transform me-thod.Then appropriate threshold parameters are adaptively determined.Finally the noise elimination is accurately achieved by this improved BM3D algorithm.Based on model and real data tests,the proposed algorithm can better eliminate random noise and protect signals than the conventional BM3D algorithm and Curvelet transform algorithm.Furthermore the proposed algorithm maintains most detailed information of boundary reflection and its computational efficiency is relatively high.

Keywords: seismic data denoising,3D block matching (BM3D),noise prior estimation,Curvelet transform,signal-noise ratio (SNR)

1.School of Geosciences,China University of Petroleum (East China),Qingdao,Shandong 266580,China

2.Laboratory for Marine Mineral Resources,Qingdao National Laboratory for Marine Science and Technology,Qingdao,Shandong 266071,China

3.Research & Development Center,BGP Inc.,CNPC,Zhuozhou,Hebei 072751,China

Seismicdatareconstructionbasedonfastfixedpointcontinuationalgorithm.PENGJiaming1,FULihua1,andZHANGXuemin1.OilGeophysicalProspecting,2019,54(6):1195-1205.

Due to factors such as terrain conditions or acquisition costs,acquired seismic data may be incomplete or irregularly distributed,which affects subsequent seismic data analysis.Therefore,it is important to reconstruct seismic data with high precision before the data processing.The fixed point continuation algorithm is a very effective reconstruction method based on the minimization of nuclear norm.However,it is based on singular value decomposition (the computation complexity of singular value decomposition isO(mnmin(m,n)),wheremandnare the dimension of the matrix).Therefore,it will take a long time to solve the problem when the dimension of the matrix is high.Using PROPACK is one of conventional acceleration ways,which can reduce the computation complexity toO(rmn),where r means the rank of observed matrix.But this way still takes a long time.To overcome this issue,an improved fast fixed point continuation algorithm is proposed in this paper,which uses the block Krylov iterative approximate singular value decomposition algorithm and subspace multiplexing technique to reduce the computation complexity of singular value decomposition toO(mcmin(m,c)),where (c?min(m,n),c∈R+).Experiments on simulating data and field seismic data show that the proposed algorithm provides much better performance than the conventional algorithm in the computation time with a reasonable signal to noise ratio.

Keywords: seismic data reconstruction,fixed point continuation algorithm,computation complexity,approximate singular value decomposition

1.School of Mathematics and Physics,China University of Geosciences (Wuhan),Wuhan,Hubei 430074,China

Asurfacewavesuppressionmethodbasedonareaadaptivepolarizationfiltering.WANGZhinong1,SUNChengyu1,WUDunshi2,andYANYuefeng1.OilGeophysicalProspecting,2019,54(6):1206-1216.

In the land 3C seismic exploration,surface waves affect seriously the subsequent data processing and interpretation.Since surface waves are characterized by low-velocity,low-frequency,and elliptical polarization,this paper proposes a surface-wave suppression method based on the area adaptive polarization filtering.First,main surface-wave distributions are confirmed according to the apparent velocity of surface wave,and the area filter is performed by S transform,so surface waves are initially separated.Then,these surface waves are analyzed with Hilbert-Huang transform (HHT) to obtian the instantanous frequency.The polarization filter window is automatically adjusted by the instantaneous frequency to perform adaptive polarization filtering.Low-frequency reflection signals are separated from surface waves to compensate results of the area filtering.Finally seismic data after the surface-wave suppression are obtained.Both numerical simulations and real seismic data applications show that the proposed method can not only effectively suppress surface waves,but also protect low frequency signals.

Keywords: surface-wave suppression,adaptive,area filter,polarization filter,Hilbert-Huang transform (HHT)

1.China University of Petroleum (East China),Qingdao,Shandong 266580,China

2.Northwest Branch,Research Institute of Petro-leum Exploration and Development,PetroChina,Lanzhou,Gansu 730020,China

Rayleighsurface-wavedispersioncurveinversionbasedonadaptivechaosgeneticparticleswarmoptimizationalgorithm.YANGBo1,2,3,XIONGZhang-qiang1,2,3,ZHANGDazhou1,2,3,andYANGZhen-tao4,OilGeophysicalProspecting,2019,54(6):1217-1227.

In order to improve the accuracy of Rayleigh surface wave dispersion curve inversion,reduce multi-solutions in the inversion,and obtain a more accurate subsurface shear wave velocity,we propose an adaptive chaotic genetic particle swarm optimization algorithm (ACGPSO) which can simultaneously improve the global and local search capabilities.ACGPSO adopts adaptive inertia weights,sets knots of particles,and introduces the crossover and mutation operation of genetic algorithm,and the single dimensional full component chaotic local search.With the proposed algorithm,fundamental dispersion curves of a theoretical geological model without noise and with noise are inverted,and the first-order and second-order dispersion curves with noise are jointly inverted.Based on the numerical test,the proposed ACGPSO algorithm has better stability and better noise-resistance than conventional algorithms,and its joint inversion can effectively reduce multi-solutions.Real data tests prove the applicability of the proposed algorithm.

Keywords: Rayleigh surface wave,dispersion curve,particle swarm optimization algorithm,adaptive chaos genetic particle swarm optimization algorithm (ACGPSO),joint inversion

1.Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring,Ministry of Education,Central South University,Changsha,Hunan 410083,China

2.Hunan Key Laboratory of Nonferrous Resources and Geological Hazards Exploration,Changsha,Hunan 410083,China

3.School of Geosciences and Info-Physics,Central South University,Changsha,Hunan 410083,China

4.Department of Earth and Space Sciences,Southern University of Sciences and Technology,Shen-zhen,Guangdong 518055,China

Landseismicpeg-legmultipleattenuationwiththevirtualeventmethod.CUIYongfu1,LIUJiahui2,CHENMeng1,HUTianyue2,CHENFeixu1,andKUANGWeikang2.OilGeophysicalProspecting,2019,54(6):1228-1236,1245.

On land seismic data,well developed peg-leg multiples are rather difficult to be predicted and suppressed because both these multiples and primaries usually have similar NMO,stacking velocity,and frequency components.Based on the virtual events theory,this paper estimates peg-leg multiples and suppresses them with adaptive subtraction,and proposes an applicable virtual-event method for land seismic data.Compared to conventional methods,the proposed method does not require subsurface information and has higher computation efficiency.Synthetic and field data examples show that the proposed method is suitable for prestack seismic data,suppresses peg-leg multiples and highlights primary energy.

Keywords: virtual event,peg-leg multiple suppre-ssion,seismic data processing

1.Tarim Oilfield Company,PetroChina,Korla,Xinjiang 841000,China

2.School of Earth and Space Sciences,Peking University,Beijing 100871,China

Trapping-wavephenomenoneliminationonseismicdatainShunbeidesertarea.LIUBin1,SONGZhiqiang1,WANGChao2andCHENHongzhi3.OilGeophysicalProspecting,2019,54(6):1237-1245.

Trapping-wave phenomena are quite common on seismic shot records in Shunbei desert area,Taklimakan Desert hinterland.The frequency of trapping wave is around 15Hz just within the band of exploration targets,which affects greatly the seismic imaging.Our theoretical analysis demonstrates that these phenomena are caused by strong-energy shallow multi-refractions.These multi-refractions are mixed with underground reflections.In the spectrum,it shows a form of “two high sandwiched one low” with the dominant frequency of underground reflections,seems like a visual “trapping-wave”phenomenon.With the wavefield separation,shallow multi-refractions are separated and eliminated,and the seismic imaging is greatly improved.

Keywords: Shunbei area,trapping wave,spectrum,near-surface,shallow multi-refractions,signal-to-noise ratio (SNR),suppression method

1.Shengli Branch,Geophysical Corporation,SINOPEC,Dongying,Shandong 257086,China

2.Northwest Oilfield Branch Co.,SINOPEC,Luntai,Xinjiang 841600,China

3.Exploration and Development Research Institute,PetroChina Huabei Oilfield Company,Renqiu,Hebei 062552,China

Thininter-bedAVOcharacteristicsanalysisbasedonforwardmodel.LIULibin1,WANGYanguang2,andSUNChengyu3.OilGeophysicalProspecting,2019,54(6):1246-1253.

The study of thin inter-bed seismic reflections and wavefield characteristics is the basis for the thin bed reservoir characterization and hydrocarbon prediction.First based on academic analysis of thin inter-bed seismic reflections,we study four types of amplitude versus offset (AVO) characteristics.Then we establish different thin inter-bed models with different thickness,velocity,and density.Finally we use the reflectivity method for the wavefield forward modeling of these models.The main factors affecting thin inter-bed vertical reflection characteristics and the influence of different thin inter-beds on AVO response characteristics are investigated.The paper summarizes the influences of sand-mud ratio,inter-bed structures,and other factors on AVO characteristics,which may be helpful for the thin inter-bed interpretation.

Keywords: thin inter-bed,sand-mud ratio,amplitude versus offset (AVO),forward modeling

1.Geophysical Research Institute,Shengli Oilfield Branch Co.,SINOPEC,Dongying,Shandong 257022,China

2.Shengli Oilfield Branch Co.,SINOPEC,Dongying,Shandong 257022,China

3.China University of Petroleum (East China),Qingdao,Shandong 266580,China

Theeighth-orderfrequency-domainNADmethodandfull-waveforminversion.HANRubing1,2andLANGChao1.OilGeophysicalProspecting,2019,54(6):1254-1266.

The full waveform inversion (FWI) is a high precise imaging method which uses wave equation and optimal algorithm to obtain physical parameters of underground media.The forward modeling is the basis of inversion.In order to further improve the efficiency of forward modelings,this paper proposes an eighth-order nearly-analytic discretization (NAD) method to discretize a 2D acoustic wave equation in the frequency domain.The construction of high-order NAD method is deduced in detail and a class of inexact rotated block triangular preconditioned Krylov subspace method is used to solve large-scale sparse linear algebraic equations obtained after the discretization.The wavefield simulation and numerical dispersion ana-lysis show the advantages of the proposed method in suppressing the numerical dispersion and improving the computational efficiency.Specifically the wavefield can be accurately recovered when the sampling points per wave length is less than two.This exceeds the limit of sampling rate.Finally,inversion researches are carried out with the constructed forward-modeling algorithm.The frequency domain full waveform inversion is performed in two typical layered models and the Marmousi mo-del,and the high resolution,high fidelity results are obtained.These test results and inversion error curves illustrate the effectiveness and applicability of the proposed method.

Keywords: full waveform inversion (FWI),frequency domain,nearly-analytic discretization (NAD),wavefield simulation,numerical dispersion analysis

1.Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China

2.Institute of Geophysics and Geomatics,China University of Geosciences (Wuhan),Wuhan,Hubei 430074,China

Adata-drivencontrolledbeammigrationbasedonthesemblancethresholdfiltering.ZHANGRui1,HUANGJianping1,LIZhenchun1,HUZiduo2,LIUWei2,andWEIWei3.OilGeophysicalProspecting,2019,54(6):1267-1279.

The Gaussian beam migration (GBM) has been recognized as a robust and versatile depth imaging tool with accuracy comparable to the wave-equation migration and with flexibility and efficiency comparable to Kirchhoff migration.However,migration artifacts may occur when strong ambient and random noise is usually mixed in seismic data and difficult to be distinguished in GBM,which will seriously affect the imaging.Aiming at the problem,we propose a data-driven controlled beam migration (CBM) method based on the semblance analysis in this paper.Based on the semblance difference between signal and disturbance in theτ-pdomain,we first derive a formula of the semblance in theτ-pdomain according to the expression in signal analysis,and then we develop a filtering method using the semblance threshold.Meantime,we adopt a data-driven strategy to eliminate the disturbance during the Gaussian beam imaging procedure,thereby reducing migration noise.Moreover,CBM can directly extract high signal-to-noise ratio (SNR) angle domain common image gathers (ADCIGs) without complex angle mapping transformations.Model and field data tests suggest that the proposed method can improve the migration SNR of poor SNR data to a certain extent with efficiency comparable to GBM,but CBM may lose the reliability of some amplitude.Furthermore,selecting an appropriate semblance threshold is very critical.If the threshold is too small,the noise may become strong.However,the excessive threshold may also suppress part of the effective information or generate artifacts.

Keywords: Gaussian beam migration (GBM),τ-pdomain,semblance,threshold filtering,controlled beam migration (CBM),angle domain common image gathers (ADCIGs)

1.School of Geosciences,China University of Petroleum (East China),Qingdao,Shandong 266580,China

2.Northwest Branch,Research Institute of Petroleum Exploration and Development,CNPC,Lanzhou,Gansu 730020,China

3.Research Institute of Petroleum Exploration and Production,SINOPEC,Beijing 100083,China

ReversetimemigrationofdecoupledqP-andqSV-wavesinTTImediawiththeoptimalquadraticapproximation.MUXinru1,2,HUANGJianping1,2,LIZhenchun1,2,GUOXu1,2,YONGPeng1,2,andYUANShuangqi1,2.OilGeophysicalProspecting,2019,54(6):1280-1292.

In the seismic data processing,if the influence of anisotropy and the symmetry inclination of TTI medium changes are ignored,the imaging position of targets will be deviated,and even the amplitude imbalance may be caused by the caustic problem.The pseudo-shear-wave interference exists in the forward modeling and RTM when using the conventional TI coupled pseudo-acoustic wave equations,and the numerical simulation is unstable when the anisotropy parameterε<δ.To solve the problem,a new approach is proposed.By referring to the experience of predecessors,the idea of the optimal quadratic approximation (OQA) is used to approximate the accurate phase velocity formula in VTI medium,and approximate phase velocity formulas of qP-wave and qSV-wave with relatively high accuracy are obtained respectively.Then,based on the approximate phase velocity formula,the decoupled qP-wave and qSV-wave equations in TTI medium are derived.In order to realize efficient and stable numerical simulation,a hybrid finite-difference/pseudo-spectral method is used to solve the wave equations.Finally,a high-precision,high-efficiency,and stable TTI media forward modeling and RTM is established.Numerical simulation results show that the proposed method can achieve migration imaging in complex TTI media.

Keywords: reverse time migration (RTM),TTI medium,pure qP-wave,pure qSV-wave,optimal quadratic approximation (OQA),hybrid finite-difference/pseudo-spectral method

1.School of Geosciences,China University of Petroleum (East China),Qingdao,Shandong 266580,China

2.Pilot National Laboratory for Marine Science and Technology (Qingdao),Qingdao,Shandong 266000,China

Two-azimuthdeepwaterseismicdatacombinedimaginginruggedseabedareas.DENGDun1,DENGYong1,MAGuangke1,SUIBo1,LIXiaoxiao1,andOUYANGMin1.OilGeophysicalProspecting,2019,54(6):1293-1301.

Because of water-depth rapid changes in rough deep sea bottoms and complex geological structures of mid-deep layers in the north of South China Sea,narrow-azimuth 3D seismic imaging cannot meet requirements of the target evaluation.Therefore two-azimuth 3D seismic data acquisitions are conducted in the Baodao Sag,the Qiongdongnan Basin.First we analyze differences of migration velocity and anisotropic parameters in different azimuths on these data sets.Then we build velocity models of two-azimuth 3D seismic data with tomographic inversion.Finally we achieve prestack depth migration combined imaging with two-azimuth anisotropic velocity model.Seismic data examples in this area show that the proposed approach obtains more continuous and stable events and achieve better im-aging of complex structures,which are helpful for the structural interpretation and the target evaluation.

Keywords: deepwater,rough seafloor,two-azimuth seismic data,imaging,anisotropic

1.Zhanjiang Branch,CNOOC,Zhanjiang,Guangdong 524057,China

Adim-spotreservoirindicativefactorintheYinggehaiBasin.XIEYuhong1,DENGYong2,LIFang2,LIYangshen2,andPANGuangchao2.OilGeophysicalProspecting,2019,54(6):1302-1309.

Dim-spot targets in mid-deep layers with high temperature and high pressure in Yinggehai Basin have great exploration potential.Conventional reservoir prediction and fluid identification methods are rather effective for the mid-shallow bright-spot reservoir identification in the area,but can hardly identify dim-spot reservoirs.Based on the Fatti equation,a dim-spot reservoir indicative factor related only to longitudinal and transverse wave impedance is constructed with the relation of relatively small intercept for dim-spot,which can highlight differences of the Class II AVO abnormality.Numerical simulations show that this factor can be used to well identify the Class II AVO abnormality.Seismic data applications verify the validity and reliability of the proposed factor.

Keywords: Yinggehai Basin,bright-spot,dim-spot,indicative factor,Class II AVO

1.CNOOC,Beijing 100000,China

2.Zhanjiang Branch,CNOOC,Zhanjiang,Guangdong 524057,China

BasispursuitinversionforYoung’smodulusandPoisson’sratio.LIUChang1,2,3,4,LIChao5,ZHUZhenyu5,andCHENGuojun1.OilGeophysicalProspecting,2019,54(6):1310-1315.

Based on the basis pursuit theory,this paper develops an approach to directly invert Young’s modulus and Poisson’s ratio with the prestack seismic data.First based on the approximate equation of Zoeppritz equation and the relationship between elastic parameters,a linear approximate equation of seismic reflection coefficient is derived,which contains Young’s modulus,Poisson’s ratio,and density.Thereafter,Young’s modulus and Poisson’s ratio are directly inverted with the prestack seismic data based on the basis pursuit.In order to improve the stability,model constraints are added to objective functions of the basis pursuit inversion.Both model tests and real data applications show that the proposed approach can stably estimate Young’s modulus and Poisson’s ratio from seismic data.

Keywords: Young’s modulus,Poisson ratio,pre-stack inversion,basis pursuit

1.Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou,Gansu 730000,China

2.China United Coalbed Methane Corporation Ltd.,Beijing 100011,China

3.Unconventional Oil & Gas Branch,CNOOC,Beijing 100011,China

4.University of Chinese Academy of Sciences,Beijing 100049,China

5.Research Institute,CNOOC,Beijing 100028,China

Impedanceinversionofstronglyheterogeneouscarbonatereservoirbasedonamplitude-constrainedmodeling.ZHANGYuanyin1,2,SUNZandong2,HANJianfa3,AhmatjanABUDRAHMAN4,andZHANGJingting5.OilGeophysicalProspecting,2019,54(6):1316-1323.

Deeply buried carbonate reservoirs in the Tarim Basin are secondary dissolution pores and fractures which are dominated by visible dissolution caves,holes,and fractures,and characterized by strong 3D heterogeneity.They cannot be explicitly modeled by conventional facies-controlled,surface-karst modeling methods,and the storage facies controlled modeling method.Therefore an amplitude-constrained modeling method is proposed to solve this problem.First pure P-wave data are obtained with AVO effects removal.Then a colored inversion is conducted with logging data to achieve relative impedance.Finally a cross-matching is carried out with logging data to get absolute impedance for inversion constraint.This method is essentially realized in the deterministic framework and mainly contains pure P-wave data calculation,relative impedance computation,amplitude-constrained low frequency model construction,and impedance inversion.Field data tests in the ZG8 area suggest that the proposed method could avoid well data effects existed in the conventional interpolation method,and overcome the precision deficiency of processing velocity.The secondary carbonate reservoir with strong heterogeneity could be more finely delineated.

Keywords: carbonate,heterogeneity,amplitude-constrained modeling,pure P-wave data,relative impedance,colored inversion

1.Oil and Gas Survey,China Geological Survey,Beijing 100083,China

2.Laboratory for Integration of Geology and Geophysics,China University of Petroleum (Beijing),Beijing 102249,China

3.Research Institute of Exploration and Development,Tarim Oilfield Company,PetroChina,Korla,Xinjiang 841000,China

4.Research Institute of Petroleum Exploration and Production,SINOPEC,Beijing 100083,China

5.Downhole Operation,Dagang Oilfield Company,PetroChina,Tianjin 300283,China

Fault-karstcarbonatereservoirpredictionwiththespectraldecompositiondiscontinuitydetectionbasedongeneralizedStransform.JIANGXiaoyu1,SONGTao1,DUWenhui1,DAIXiaofeng1,andFANXingyan1.OilGeophysicalProspecting,2019,54(6):1324-1328.

This paper focuses on an approach to the fault-karst carbonate reservoir characterization on seismic data with disordered facies.A discontinuity detection method combining coherence with the generalized S-transform spectrum decomposition is adopted on the basis of conventional discontinuity detection.After the calculation of spectral decomposition based on the generalized S transform,the adaptive dominant frequency optimization is used to obtain data volumes of amplitude spectrum with different depths and different scales,which can be used as inputs of discontinuity detections.Thus the adaptive multi-scale discontinuity analysis of the original seismic data is realized and subtle faults caused by edge collapses of fault-karst carbonate reservoirs are depicted.Compared with conventional discontinuity attributes,this approach can better detect subtle changes of formations and has a higher noise-resistance.Our study proves the validity of the proposed approach for the fault-karst reservoir characterization.

Keywords: S transform,coherence,spectrum decomposition,discontinuity detection,fault-karst

1.Research Institute of Petroleum Exploration & Development,CNPC,Beijing 100083,China

Amethodforestablishinganddirectlyextractingsensitiveidentificationfactorsofunconsolidatedsandstones.GAOGang1,2,YANGYahua3,ZHAOBin1,2,DUANHongliang4,WANGXiaoyang5,andWEIYazhai6.OilGeophysicalProspecting,2019,54(6):1329-1338,1347.

Many literatures prove that sensitive identification factors are successfully used to predict reservoir lithology,fluids,and rock brittleness.However,very few researches focus on the establishment of sensitive identification factors of reservoir and its direct extraction methods.We demonstrate this kind of research in shallow-sandstone reservoirs in Huangjue area.Firstly,a sensitive identification factor in sand reservoirs is designed for SF4 based on high P-wave velocity (vP),high S-wave velocity (vS),and low density (ρ),which effectively avoids numerical overlaps of conventional sand and mud identification factors (velocity multiplied by density).Then the AVO approximation containing the sensitive sand identification factor is derived which decreases accumulative errors caused by indirect calculations.Finally,the sensitive sand identification factor is directly extracted using the Bayesian-based elastic parameter inversion and the low frequency component of the inversion can be compensated by introducing the soft low-frequency constraint.Numerical tests and real data examples prove the validity and practicability of the proposed method.

Keywords: direct extraction,lithology identification,AVO approximation,Bayesian inversion

1.Key Laboratory of Exploration Technologies for Oil and Gas Resources (Yangtze University),Ministry of Education,Wuhan,Hubei 430100,China

2.College of Geophysics and Petroleum Resources,Yangtze University,Wuhan,Hubei 430100,China

3.School of Geosciences,China University of Petroleum (East China),Qingdao,Shandong 266580,China

4.Jiangsu Oilfield Branch Co.,SINOPC,Yangzhou,Jiangsu 225009,China

5.Southwest Branch,BGP Inc.,CNPC,Chengdu,Sichuan 610213,China

6.Dagang Branch,GRI,BGP Inc.,CNPC,Tianjin 300280,China

Faultbreakpointassemblagetypesofsand-mudinter-beds:anexampleofSaertuOilfieldinDaqing.LIUShufen1,FENGYaoguo2,GONGLei1,JIAOTong1,andSHENGZhicheng1.OilGeophysicalProspecting,2019,54(6):1339-1347.

Based on the understanding of the fault breakpoint ownership of complex fault blocks and on previous studies results,a research of fault breakpoint assemblage types of sand-mud inter-beds in Saertu Oilfield,Daqing is carried out.The fault breakpoint assemblage types with throw of less than 5m in sand-mud inter-beds are summarized from the aspects of fault combination,fault binary structure,fault vertical segmental growth,and seismic fault terminal portion.The following observations are obtained: ①There are four types of fault breakpoint assemblage,such as fault intersection,single fault fracture zone,fault vertical segment,and the seismic fault terminal portion.The corresponding representation of theses breakpoint assemblages in space,plane,and section is established; ②Breakpoints of fault intersection are mainly classified by seismic fault identification,their throws vary greatly,and the breakpoint vertical distance is less than 40m.Fault breakponts with small throws belong to fault fracture zones.For releasing vertical segmental breakpoints,throws are almost equal,and there are plastic layers among breakpoints.For restraining vertical segmental fault breakpoints,there are plastic layers with a larger thickness,in which Faults experienced multi-stages.Terminal portion breakpoint of seismic fault is located in the direction of fault extension and accords with the law of fault throw-distance curve; ③Based on this research,52 breakpoints with throws from 5m to 10m are identified,the overall breakpoint assemblage ratio reaches 93.3 %.The breakpoint assemblage ratio with throws smaller less than 5m is 81.8 %.It provides accurate and useful data for of fault characteristics analysis,fault model building,and remaining oil development.

Keywords: fault breakpoint assemblage,multiple breakpoints in one well,scattered fault breakpoints,Saertu Oilfield

1.College of Earth Sciences,Northeast Petroleum University,Daqing,Heilongjiang 163318,China

2.No.2 Oil Production Plant,Daqing Oilfield Company,PetroChina,Daqing,Heilongjiang 163514,China

Quantificationofbraidedriver-deltasandbodybasedonseismicsedimentology:anexampleoftheBlockMPE-3inVenezuela.LIUShuting1,ZHANGXianguo1,RENLihua1,LINChengyan1,LINFang1,andHUANGWensong2.OilGeophysicalProspecting,2019,54(6):1348-1356.

This paper presents a research of braided river-delta reservoir in the Bock MPE-3,Venezuela.Based on vertical- and horizontal-well and 3D seismic data,a sequence stratigraphic framework in the study area is constructed with the seismic sequence boundary,90°-phase transformation,and stratal slices,and 6 fourth-order sequences are identified within the third-order sequence.Using the seismic sedimentology approach such as lateral high-resolution horizontal well data to calibrate stratal slices,fine-grained inter-beds formed by gullies in sand bodies are identified,which effectively improves the slice interpretation accuracy.The paper summarizes quantitative characteristics of sediments such as channel bars with the joint use of well and seismic data,establishes quantitative relationships among channel bar length and width,braided channel width,and gully width,which may provides a solid foundation for the future development.

Keywords: braided-delta,horizontal well,sequence stratigraphic framework,phase transformation,stratal slice,seismic sedimentology

1.School of Geosciences,China University of Petroleum (East China),Qingdao,Shandong 266580,China

2.Research Institute of Petroleum Exploration & Development,CNPC,Beijing 100083,China

FluididentificationingluteniteswiththemachinelearningAdaBoost.M2algorithm.CHENGanghua1,LIANGShasha1,2,WANGJun3,DIShuhua4,ZHUGEYueying4,andLIUYouji1.OilGeophysicalProspecting,2019,54(6):1357-1362.

Glutenites are usually characterized by complex compositions,various pore structures,and strong heterogeneity,and the logging response of fluid is much smaller than that of gravel skeleton.So fluids in glutenites cannot be identified with conventional logging methods.Therefore we propose the machine learning AdaBoost.M2 algorithm for glutenite fluid identification.First combined with oil test data,the AdaBoost.M2 algorithm disassembles theK-class multi-fluid type classification problem into a two-class problem,and the sample distribution is obtained through multi-iterations.Then the decision tree algorithm called a weak learning algorithm obtains automatically a classifierhtfor the discrimination.The proposed algorithm is applied to the reservoir fluid identification in A area.The sample return accuracy is 95% and the test accuracy is 91.5%,which proves the validity and applicability of proposed algorithm.

Keywords: machine learning,AdaBoost.M2 algorithm,glutenite,fluid identification

1.School of Geosciences,China University of Petroleum (East China),Qingdao,Shandong 266580,China

2.Jiaxing Jia’an Gas Technology Service Limited,Jiaxing,Zhejiang 314000,China

3.Research Institute of Exploration and Development,Shengli Oilfield Branch Co.,SINOPEC,Dongying,Shandong 257015,China

4.North China Branch,Logging Co.,Ltd.,CNPC,Renqiu,Hebei 062550,China

APearsoncorrelationcoefficientimprovedbyspatialweight.HANSheng1,HANJianzhou2,ZHAOXuan3,WANGXiaoxuan1,FANLihong1,andMEIJie1.OilGeophysicalProspecting,2019,54(6):1363-1370.

The correlation coefficient is a kind of indicator for measuring the statistical relationship between two variables.Existing correlation coefficients calculate only the relationship in the values,but do not take in account of the variables’ positions.So the rhythmicity of data is not fully explored.It is well known that the distribution of hydrocarbon is closely related to its geographical location in the hydrocarbon exploration.This paper combines generalized Pearson product-moment correlation coefficient with spatial weighs to calculate data local correlation,and analyze spatial correlation characteristics of two data sets with different searching radius.Based on synthetic and field data tests,the proposed approach demonstrates a spatial relationship between two variables,which is helpful for the hydrocarbon exploration.

Keywords: Pearson correlation coefficient,local correlation coefficient,spatial weight,coalbed methane,reservoir characterization

1.Exploration and Development Research Institute,Huabei Oilfield Company,PetroChina,Renqiu,Hebei 062550,China

2.No.5 Oil Production Plant,Huabei Oilfield Company,PetroChina,Xinji,Hebei 052360,China

3.Logging Branch 2,Bohai Drilling Engineering Company Limited,CNPC,Renqiu,Hebei 062552,China

Asecantinfiniteapproximationalgorithmforthefull-timeapparentresistivityintransientelectromagneticmethod.ZENGQingning1,2,LUOYing2,LIUShuai2,andLONGChao1,2.OilGeophysicalProspecting,2019,54(6):1371-1375.

In the geology exploration with the transient electromagnetic method (TEM),the apparent resistivity calculation is quite important as the appa-rent resistivity may intuitively indicate underground geological bodies.However,conventional approximation formulas usually lead a large error in the apparent resistivity calculation.According to the characteristics of implicit functions of apparent resistivity for half-space central-loop TEM,we propose in this paper a secant infinite approximation algorithm for the full-time apparent resistivity in the transient electromagnetic method,in which the secant method is used to calculate the roots of non-linear functions.The proposed algorithm avoids complicated derivative calculations of implicit functions.Simulation and real data examples show that the proposed algorithm has faster convergence than the bisection algorithm and can calculate with arbitrary accuracy the full-time apparent resistivity for half-space central-loop TEM.

Keywords: transient electromagnetic method(TEM),apparent resistivity,inversion,secant method

1.Key Laboratory of Cognitive Radio and Information Processing,Ministry of Education,Guilin University of Electronic Technology,Guilin,Guangxi 541004,China

2.College of Information and Telecommunications,Guilin University of Electronic Technology,Gui-lin,Guangxi 541004,China

Aninvernsionschemewithlateralsegmented-combinedconstraintsfortime-domainairborneelectromagneticdata.LINXingyuan1,LUCongde1,ZHONGBinghui2,andFANChongxiao1.OilGeophysicalProspecting,2019,54(6):1376-1382.

In order to ensure lateral continuity,lateral roughness constraints are applied in the inversion of time-domain airborne electromagnetic data.However,the lateral roughness constraint inversion requires multiple points to be calculated simultaneously and the calculation time of inversion increases sharply when the number of points increases up to a certain amount.Taking into account the lager data set of time-domain airborne electromagnetic,we propose an inversion scheme with lateral segmented-combined constraints.First,observation points are segmented.Then the lateral and vertical roughness constraints are used simultaneously in each data segment,and the lateral priori information constraint is used between the segments.Finally,effects of lateral and vertical roughness constraints and lateral prior information constraints on inversion accuracy and computation time are analyzed.The proposed inversion scheme can effectively reduce the calculation time with the segmentation.The lateral and vertical roughness constraints can ensure high inversion accuracy.Test of modeling data and real data verify the validity,calculation effectivity,and applicability of the proposed invernsion scheme.

Keywords: time-domain airborne electromagnetic method,segmented inversion,laterally constrained inversion,combined constraints

1.College of Geophysics,Chengdu University of Technology,Chengdu,Sichuan 610059,China

2.College of Information Science and Technology,Chengdu University of Technology,Chengdu,Sichuan 610059,China

Forwardmodelingfor2D-bodygravityanomalyinthespace-wavenumbermixeddomain.DAIShikun1,2,WANGXulong1,2,ZHAODongdong1,2,LIUZhiwei3,ZHANGQianjiang4,andSUNJinfei5.OilGeophy-sicalProspecting,2019,54(6):1383-1389.

An efficient and high-precision forward modeling of 2D-body gravity anomaly in a space-wavenumber mixed domain is proposed to calculate the gravity anomaly in the case of arbitrary density distribution.By performing 1D Fourier transform,2D partial differential equation governing gravity potential in the spatial domain is transformed into a group of independent 1D differential equations engaged with different wavenumbers.The method preserves the vertical direction in the spatial domain,thus shallow and deep meshes for modeling can be fine and coarse respectively.By this way,both the accuracy and the efficiency of calculation are taken into account.1D finite element method is used to solve the transformed differential equations with different wave numbers.Moreover,the efficiency of solving linear equations with a fixed bandwidth assembled by the finite element analysis is further improved by a chasing method.To test the proposed algorithm,a constant-density 2D model and a variable-density 2D model are designed.Numerical test results show that the proposed algorithm not only guarantees the calculation accuracy,but also improves the calculation efficiency compared with the conventional methods.

Keywords: gravity anomaly,space-wavenumber mixed domain,2D body,forward modeling

1.Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring,Ministry of Education,Changsha,Hunan 410083,China

2.School of Geosciences and Info-physics,Central South University,Changsha,Hunan 410083,China

3.Guangdong Electric Power Design Institute,China Energy Engineering Group CO.,Guangzhou,Guangdong 510663,China

4.College of Earth Sciences,Guilin University of Technology,Guilin,Guangxi 541004,China

5.No.1 Daqing Geophysical Exploration Company of BGP,CNPC,Daqing,Heilongjiang 163357,China

Normalizedtotalgradientofgravityanomalybasedonthedownward-continuationMilnemethod.SHIJiaqiang1,XIAOFeng1,andZHONGYang1.OilGeophysicalProspecting,2019,54(6):1390-1396.

The normalized total gradient method of gra-vity anomaly includes multi-calculations of downward continuation and vertical derivative,both of them amplify the high wavenumber components.To sovle the problem,we propose a new idea for the issue in this paper.Two stable algorithms,Milne method of downward continuation and integrated vertical second derivative method,are used for the normalized total gradient of gravity anomaly.The improved method is applied to locate the center of the infinite horizontal cylinder model,and the result is accurate.In the real gravity anomaly profile data processing,compared with the norma-lized total gradient of gravity anomaly based on Taylor series expansion,this proposed method obtains the more accurate location of the mine center,which proves the validity and practicality of the proposed method.

Keywords: normalized total gradient of gravity anomaly,downward-continuation Milne method,integrated vertical second derivative

1.College of Geo-Exploration Sciences and Technology,Jilin University,Changchun,Jilin 130026,China

Progressandoutlookofnear-surfacequalityfactorQmeasurementandinversion.ZHAOQiufang1,2,YUNMeihou1,2,ZHULibo3,LIXiaobin1,2,andLIWeina1.OilGeophysicalProspecting,2019,54(6):1397-1418.

The accurate determination of near-surface quality factorQis an important basis for constructing near-surface attenuationQmodels and implementing inverseQfiltering to improve the seismic resolution.Based on our analysis,the existing near-surfaceQ-value estimation methods may be divided into two categories:Q-value estimation with rock sample testing andQ-value estimation with stratum in-situ survey data.For the first category there are three approaches: stress-strain,standing wave,and travel wave according to different test principles.For the latter category,there are four methods: uphole survey,shallow first breaks from common-shot-point (CSP),and surface wave method according to different field survey techniques.In this paper we analyze the principles,application conditions,detection ranges,advantages and disadvantages of the methods.TheQvalue estimation based on rock sample testing has a high accuracy.However,due to the limitations of the sample and the incongruity between the measurement frequency and the seismic frequency,estimated values have lots of limitations in the seismic exploration.Both the uphole survey and the shallow refraction methods can obtain more accurateQestimations with high vertical resolution,but they can hardly show horizontalQvalue changes.The shallow refraction is limited by surface survey conditions.The first breaks method can obtain the averageQvalue of low velocity layers,and can better describes lateral variations ofQvalues,but its vertical resolution is insufficient.The first break refraction cannot show attenuation characteristics of near-surface high-velocity layers.The vibroseis seismic first breaks method is not subject to this restriction,it can obtain the same precision vertical resolution as the shallow refraction,and betterQvalue lateral variations.The surface wave method is mainly based on Rayleigh-wave,including the Rayleigh-wave from CSP records.The detection depth is relatively shallow,which usually reveals weathering layerQvalues.Besides,the accuracy ofQestimation of this method is limited by the precision of velocity dispersion curves.So,the development tendency of near-surfaceQinversion will be multi-information joint application such as surface and borehole seismic integration in the future.

Keywords: near-surface,quality factor,sample testing,in-situ survey,spectral ratio method,tomography inversion

1.Institute of Resources Environment,Henan Po-lytechnic University,Jiaozuo,Henan 454000,China

2.Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Econo-mic Region,Jiaozuo,Henan 454000,China

3.Daqing Branch,BGP Inc.,CNPC,Daqing,Heilongjiang 163357,China