Application of 9-component S-wave 3D seismic data to study sedimentary facies and reservoirs in a biogasbearing area:A case study on the Pleistocene Qigequan Formation in Taidong area,Sanhu Depression,Qaidam Basin,NW China

To solve the problems in restoring sedimentary facies and predicting reservoirs in loose gas-bearing sediment,based on seismic sedimentologic analysis of the first 9-component S-wave 3D seismic dataset of China,a fourth-order isochronous stratigraphic framework was set up and then sedimentary facies and reservoirs in the Pleistocene Qigequan Formation in Taidong area of Qaidam Basin were studied by seismic geomorphology and seismic lithology.The study method and thought are as following.Firstly,techniques of phase rotation,frequency decomposition and fusion,and stratal slicing were applied to the 9-component S-wave seismic data to restore sedimentary facies of major marker beds based on sedimentary models reflected by satellite images.Then,techniques of seismic attribute extraction,principal component analysis,and random fitting were applied to calculate the reservoir thickness and physical parameters of a key sandbody,and the results are satisfactory and confirmed by blind testing wells.Study results reveal that the dominant sedimentary facies in the Qigequan Formation within the study area are delta front and shallow lake.The RGB fused slices indicate that there are two cycles with three sets of underwater distributary channel systems in one period.Among them,sandstones in the distributary channels of middle-low Qigequan Formation are thick and broad with superior physical properties,which are favorable reservoirs.The reservoir permeability is also affected by diagenesis.Distributary channel sandstone reservoirs extend further to the west of Sebei-1 gas field,which provides a basis to expand exploration to the western peripheral area.

Integrated application of 3D seismic and microseismic data in the development of tight gas reservoirs

The development of unconventional resources, such as shale gas and tight sane gas, requires the integration of multi-disciplinary knowledge to resolve many engineering problems in order to achieve economic production levels. The reservoir heterogeneit3 revealed by different data sets, such as 3D seismic and microseismic data, can more full3 reflect the reservoir properties and is helpful to optimize the drilling and completioT programs. First, we predict the local stress direction and open or close status of the natura fractures in tight sand reservoirs based on seismic curvature, an attribute that reveals reservoi heterogeneity and geomechanical properties. Meanwhile, the reservoir fracture network is predicted using an ant-tracking cube and the potential fracture barriers which can affec hydraulic fracture propagation are predicted by integrating the seismic curvature attribute anc ant-tracking cube. Second, we use this information, derived from 3D seismic data, to assis in designing the fracture program and adjusting stimulation parameters. Finally, we interpre the reason why sand plugs will occur during the stimulation process by the integration of 3E seismic interpretation and microseismic imaging results, which further explain the hydraulic fracure propagation controlling factors and open or closed state of natural fractures in tigh sand reservoirs.

Deep-large faults controlling on the distribution of the venting gas hydrate system in the middle of the Qiongdongnan Basin, South China Sea

Many locations with concentrated hydrates at vents have confirmed the presence of abundant thermogenic gas in the middle of the Qiongdongnan Basin(QDNB).However,the impact of deep structures on gasbearing fluids migration and gas hydrates distribution in tectonically inactive regions is still unclear.In this study,the authors apply high-resolution 3D seismic and logging while drilling(LWD)data from the middle of the QDNB to investigate the influence of deep-large faults on gas chimneys and preferred gasescape pipes.The findings reveal the following:(1)Two significant deep-large faults,F1 and F2,developed on the edge of the Songnan Low Uplift,control the dominant migration of thermogenic hydrocarbons and determine the initial locations of gas chimneys.(2)The formation of gas chimneys is likely related to fault activation and reactivation.Gas chimney 1 is primarily arises from convergent fluid migration resulting from the intersection of the two faults,while the gas chimney 2 benefits from a steeper fault plane and shorter migration distance of fault F2.(3)Most gas-escape pipes are situated near the apex of the two faults.Their reactivations facilitate free gas flow into the GHSZ and contribute to the formation of fracture‐filling hydrates.

Beamforming with the Generalized Sidelobe Cancellerfor Coherent Noise Attenuation in 3D Seismic Data

This paper presents a new approach for attenuating coherent noise in 3D seismic data. An adaptive beamforming with generalized sidelobe canceller (GSC) design methodology is utilized here as a general form of linearly constrained adaptive beamforming structure. It consists of a fixed beamformer, and a signal-blocking matrix in front of an unconstrained adaptive beamformer.Considerationf of the complexity of the geometry for 3D seismic survey, the 3D beamforming with GSC technique is developed with two key points: (1) sorting along azimuth sections to simplify the relationship between traveltime and offset from 3D to 2D, and (2) dynamic binning scheme to avoid the possible poor folding in some azimuth sections. Both simulation result and real data example show that the newly developed 3D beamforming with GSC yields more credible results at a relative low cost, sufficient stability and good resolution.

3D Seismic Acquisition Technology and Effect in HX Volcanic Area in Liaohe Depression

Multi-stages volcanic are available in HX area, shielding the seismic waves. Previous seismic acquisitions of large size bin, less fold coverage and narrow azimuth result in indistinct fault images, low S/N ratio and the difficulty of multi-stages volcanic characterization. In reference to the successful experience of domestic and overseas volcanic exploration, the low frequency excitation and receiving, and survey with wide range, high coverage, wide azimuth should be paid more attention, associated with two-dimensional and three-dimensional wave equation forward modeling and real data processing contrast analysis method. The image of underlying strata and fault are remarkably improved in the new method, according to the processing results of new seismic data. The new method will provide technical reference for the similar volcanic development area in the future seismic acquisition design.

Sedimentary microfacies of the H8 member in the Su14 3D seismic test area

The distribution of sedimentary microfacies in the eighth member of the Shihezi formation（the H8 member） in the Sul4 3D seismic test area was investigated.A Support Vector Machine（SVM） model was introduced for the first time as a way of predicting sandstone thickness in the study area.The model was constructed by analysis and optimization of measured seismic attributes.The distribution of the sedimentary microfacies in the study area was determined from predicted sandstone thickness and an analysis of sedimentary characteristics of the area.The results indicate that sandstone thickness predictions in the study area using an SVM method are good.The distribution of the sedimentary microfacies in the study area has been depicted at a fine scale.

Application of 3D Seismic Data Inversion to Coal Mining Prospecting

Seismic inversion is one of the most important methods for lithological prospecting . Seismic data with lowresolution is converted into impedance data of high resolution which can reflect the geological structure by inversionThe inversion technique of 3D seismic data is discussed from both methodological and theoretical aspects, and the in-version test is also carried out using actual logging data. The result is identical with the measured data obtained fromroadway of coal mine. The field tests and research results indicate that this method can provide more accurate data foridentifying thin coal seam and minor faults.

3D HIGH RESOLUTION SEISMIC PROSPECTING IN MINING AREAS,XIEQIAO COLLIERY

3D seismic prospecting in mining areas of Xieqiao Colliery is a successfulmodel for an advancement from the resource prospecting to mining prospecting stagein coal fields. Its results have proved that faults with a throw of 5-10 m can be detected in an area with good seismogeologic conditions by using 3D seismic technique.Detection of underground tunnels for the first time utilizing 3D seismic data indicates that subsided columns, gotten and mine goaf can be detected using 3D seismic technique, so it has a broad applied prospect.

Geological Interpretation and Identification of Albian-Aged Petroleum Prospects in Block A, San Pedro Margin (Côte d’Ivoire)

The study aims to identify Albian-age oil prospects in Block A of the San Pedro margin, Côte d’Ivoire, by conducting a detailed geological interpretation. The objective is to confirm the presence of oil reservoirs trapped by favorable geological structures, identifiable through geophysical and seismic methods. The methodological approach is based on a combined analysis of studies and seismic data. Drilling data from well PA, including well logs and end-of-well reports, were used to characterize the lithological formations encountered, particularly those of the Albian. 3D seismic profiles were interpreted to identify structures conducive to hydrocarbon accumulation. Isochrone, isovelocity, and isobath maps were developed to refine the interpretation. Sedimentological analyses revealed five sandy/gritty levels between 2610 m and 3100 m, interspersed with clay, limestone, and siltstone beds. The seismic profiles highlighted two main prospects. These prospects exhibit favorable geological structures, including normal faults and structural traps that provide oil traps.

Study on the 3D Seismic Data Field Hybrid Rendering Technique of Natural Gas Hydrate and Its Application

3D visualization technology is a tool used for displaying, describing, and understanding the characteristics of geologic bodies, and features high efficiency, objective accuracy, visual expression, etc. In this paper, the man-machine interactive interpretation and 3D visualization technology rapidly displaying and analyzing the 3D seismic data of hydrate ore volume is researched and developed using the hybrid rendering technique. Through the integrated interpretation on the 3D space structure, stratum, and seismic attributes, the visualized multi-attribute superimposition analysis is implemented for describing the spatial distribution characteristics of hydrate ore volume and exquisitely describing the subtle geological characteristics of hydrate ore volume. By the hybrid rendering technique, authentication and interpretation are provided for the geological exploration work, so as to greatly enhance the visualization and accuracy of the geological analysis, and also provide a good decision-making foundation for the subsequent development of resources.

3D HIGH RESOLUTION SEISMIC PROSPECTING IN COAL MINING AREAS

The production capacity and efficiency for mechanized coal faces of large-scale mines depend on the detecting degree of mining structures. It is a major task for geological exploration in coal fields to detect minor structures in district. 3D high resolution seismic prospecting is a effective measure for solving this problem.

EVG-3D墙板耐火性能及火灾加固后的抗震性能试验研究

介绍一种新型墙材——EVG-3D墙板。通过火灾试验以及火灾墙板加固后进行拟静力试验,研究墙板的耐火极限、火灾加固后的破坏形态、承载力、刚度、延性比、滞回耗能等性能。通过计算分析墙体的抗剪承载力,表明火灾加固后的墙板仍具有良好的抗剪性能,可作为承重墙使用。

2—D与3—D横向各向同性介质中地震波动方程的解耦

在2-D横向各向同性介质中,似P波与似SV波耦合;3-D介质中,似P波与似SV波及似SH波均耦合于偏微分波动方程组中,为便于2-D与3-D横向各向同性介质中震波激发以及地震记录合成研究,本文首先对波动方程组本身进行了讨论,进而分别研究了二维与三维横向各向同性介质中波动方程组的解耦问题,得到了解耦后的关于位移分量偏微分方程。

3.5D地震勘探实例研究

3D和随时间推移(TL)地震是油田评价与开发阶段重要的地震勘探方法。近年来,TL地震正逐步成为油藏开发和管理中的重要手段之一。但TL地震受到储层条件、开采方式、TL地震勘探过程中非重复性噪声以及一些油田在开发早期未开展基础3D地震观测等诸因素的影响,这些因素使得这一技术在陆上油田开发中的应用受到了制约。为此,提出了3.5D地震勘探方法。3.5D地震勘探方法应用油田开发中、晚期的高精度3D地震数据,结合油田开发动态信息解决油田开发中存在的问题,寻找剩余油气分布区域。通过对中国西部某油田的开发实例研究,认为:3.5D地震可以较有效地解决油田开发中的问题,发现剩余油气的分布,不但解决了一些油田早期没有3D地震或早期3D地震数据质量存在严重非重复性噪声影响的问题,同时还可降低TL地震勘探的风险,提高油田开发的经济效益。

汶川地震发震构造带过WSFD-2钻井深反射地震数据3-D处理技术研究

2008年5月12日汶川发生里氏8.0级地震的发震机制与龙门山断裂带的构造特征紧密相关,应用反射地震探测方法精细探测发震构造内部的结构特征,对研究汶川地震的发震机理有重要意义.5.12地震后在地表错断最剧烈的区域之一虹口乡白庙村穿过发震构造和深钻科研井WSFD-1和WSFD-2布置了兼顾浅中深层信息的反射地震探测剖面,该区域断裂带硬岩出露,地形地貌复杂多变,起伏剧烈,只能采取弯线地震测线布设方式采集二维反射地震数据,而且弯曲度大,造成CDP点分散严重.区域内构造复杂,褶皱逆推构造发育,地层和构造倾角大,采用常规二维地震数据处理方法进行叠加处理时,易将不同地层的反射信息叠加到同一反射层.弯线叠加剖面上侧面波,混波干扰严重,会显著地降低原本低信噪比数据的分辨率,或剖面可靠性低,容易在二维剖面中造成解释陷阱.本文利用弯线地震采集的三维特性,用拟三维地震叠加技术处理汶川地震科学钻井附近横跨北川—映秀断裂带的二维弯线地震数据,弥补常规二维弯线地震数据处理技术的不足,将不同地层的反射信息分离归位到不同的三维叠加剖面上,解决二维弯线地震数据处理时混波干扰严重的难题.通过理论分析和实验选取合适的共中心点面元,获得了高分辨率的三维叠加剖面.相比于二维弯线叠加剖面,三维叠加剖面切片成像更真实,剔除了不同地层反射信息混叠的影响,能得到更准确的断点信息,并可以获得沿断层走向横向的信息,显著提高了构造解释的可靠性和精度.应用拟三维地震数据处理方法处理龙门山断裂带的二维弯线地震数据,获取高分辨率的构造信息,有利于断裂带内汶川地震发震机制和龙门山隆起机制的解释.

3-D叠后地震资料多项式拟合提高信噪比和道内插

三维地震资料叠后提高信噪比和横测线方向道内插问题，目前在生产中还没有得到很好的解决。现在有些数据中心是用二维多项式拟合提高信噪比模块对纵测线和横测线分两步进行处理的。本文应用多项式拟合理论直接在三维叠后地震资料上完成提高信噪比和横测线方向的道内插（通常横测线方向的道间距要比纵测线方向的道间距大一倍，需要进行道内插），用一步处理即可得到能应用于三维偏移的共深度点数据集。此法充分利用了三维地震资料的信息，提高了处理效率。

Deep seismic sounding investigation into the deep structure of the magma system in Changbaishan-Tianchi volcanic region

The magma system of Changbaishan-Tianchi Volcanic region is studied with three-dimensional deep seismic sounding (DSS) technique. The results show that the magma system of Changbaishan-Tianchi volcanic region, mainly characterized by low velocity of P wave, can be divided into three parts in terms of depth. At the depth range of 9-15 km, the distribution of the magma system is characterized by extensiveness, large scale and near-SN orientation. This layer is the major place for magma storage. From the depth of 15 km down to the lower crust, it is characterized by small lateral scale, which indicates the 'trace' of magma intrusion from the upper mantle into the crust and also implies that the magma system most probably extends to the upper mantle, or even deeper.(less than 8-9 km deep), the range of magma distribution is even smaller, centering on an SN-oriented area just north of the Tianchi crater. If low velocity of P wave is related to the magma system, it then reflects that the magma here is still in a state of relatively high temperature. In this sense, the magma system of Changbaishan-Tianchi volcanic region is at least not 'remains', in other words, it is in an 'active' state.

Tectonic characteristics and structural styles of a continental rifted basin:Revelation from deep seismic reflection profiles

The Fushan Depression is a half-graben rifted sub-basin located in the southeast of the Beibuwan Basin, South China Sea. The Paleogene Liushagang sequence is the main hydrocarbon-bearing stratigraphic unit in the sub-basin. Using three-dimensional（3-D）seismic data and logging data over the sub-basin, we analyzed structural styles and sedimentary characteristics of the Liushagang sequence. Five types of structural styles were defined： ancient horst, traditional slope, flexure slope-break, faulted slope-break and multiple-stage faults slope, and interpretations for positions, background and development formations of each structural style were discussed. Structural framework across the sub-basin reveals that the most remarkable tectonic setting is represented by the central transfer zone（CTZ） which divides the sub-basin into two independent depressions, and two kinds of sequence architectures are summarized：（i） the western multi-stage faults slope;（ii） the eastern flexure slope break belt. Combined with regional stress field of the Fushan Depression, we got plane combinations of the faults, and finally built up plan distribution maps of structural system for main sequence. Also, we discussed the controlling factors mainly focused on subsidence history and background tectonic activities such as volcanic activity and earthquakes. The analysis of structural styles and tectonic evolution provides strong theoretical support for future prospecting in the Fushan subbasin and other similar rifted basins of the Beibuwan Basin in South China Sea.

A study on 3-D velocity structure of crust and upper mantle in Sichuan -Yunnan region, China

Based on the first arrival P and S data of 4 625 regional earthquakes recorded at 174 stations dispersed in the Yunnan and Sichuan Provinces, the 3-D velocity structure of crust and upper mantle in the region is determined, incorporating with previous deep geophysical data. In the upper crust, a positive anomaly velocity zone exists in the Sichuan basin, whereas a negative anomaly velocity zone exists in the western Sichuan plateau. The boundary between the positive and negative anomaly zones is the Longmenshan fault zone. The images of lower crust and upper mantle in the Longmenshan fault, Xianshuihe fault, Honghe fault and others show the characteristic of tectonic boundary, indicating that the faults likely penetrate the Moho discontinuity. The negative velocity anomalies at the depth of 50 km in the Tengchong volcanic area and the Panxi tectonic zone appear to be associated with the temperature and composition variations in the upper mantle. The overall features of the crustal and the upper mantle structures in the SichuanYunnan region are the lower average velocity in both crust and uppermost mantle, the large crustal thickness variations, and the existence of high conductivity layer in the crust or/and upper mantle, and higher geothermal value. All these features are closely related to the collision between the India and the Asia plates. The crustal velocity in the SichuanYunnan rhombic block generally shows normal value or positive anomaly, while the negative anomaly exists in the area along the large strike-slip faults as the block boundary. It is conducive to the crustal block side-pressing out along the faults. In the major seismic zones, the seismicity is relative to the negative anomaly velocity. Most strong earthquakes occurred in the upper-mid crust with positive anomaly or normal velocity, where the negative anomaly zone generally exists below.

Seismic geomorphology and stratigraphic trap analyses of the Lower Cretaceous siliciclastic reservoir in the Kopeh Dagh-Amu Darya Basin

Lower Cretaceous Shurijeh–Shatlyk Formations host some of the main reservoirs in the Kopeh Dagh-Amu Darya Basin.Exploration in this area so far has focused on the development of structural traps, but recognition of stratigraphic traps in this area is of increasing importance. Integration of 3D seismic data with borehole data from thirteen wells and five outcrop sections was used to identify potential reservoir intervals and survey the hydrocarbon trap types in the East Kopeh Dagh Foldbelt(NE Iran). Analyses of horizontal slices indicated that the lower Shurijeh was deposited in a braided fluvial system.Generally, three types of channel were identified in the lower Shurijeh Formation: type 1, which is low-sinuosity channels interpreted to be filled with non-reservoir fine-grained facies;type 2, which is a moderately sinuous sand-filled channel with good prospectively;and type 3, which is narrow, high sinuosity channel filled with fine-grained sediments. Results indicate that upper Shurijeh–Shatlyk Formations were deposited in fluvial to delta and shallow marine environments. The identified delta forms the second reservoir zone in the Khangiran Field. Study of the stratigraphic aspects of the Shurijeh succession indicates that both lower and upper Shurijeh reservoirs are stratigraphic reservoir traps that improved during folding.