Optical fiber sensing has been applied to surface,marine,and borehole seismic acquisition and joint borehole-surface seis-mic acquisition in the latest years.Surface or marine seismic and VSP seismic exploration could be combined to achieve 3D prospec-ting.Using 3D DAS-VSP data,we could obtain accurate time-depth relationship,interval velocity,deconvolution operator,compen-sation factor of spherical spreading,absorption attenuation factor,anisotropy parameters,and high-resolution structure imaging a-round the well bore;above parameters could be used to enhance 3D well-driven land or marine seismic data processing.In this work we performed 3D DAS-VSP data processing and imaging.The 3D DAS-VSP survey was acquired using a downhole armored optical cable with simultaneous OBN data acquisition in the East China Sea.The routine workflow of 3D DAS-VSP data processing includes geometry definition,preprocessing,first break picking,static correction,amplitude compensation,deconvolution,wave field separation,velocity analysis and modeling,and structure imaging using upgoing waves.A new technique of downgoing multiple re-flection imaging is developed to enlarge the migration aperture and imaging area of upgoing reflected waves and obtain better quali-ty of imaging.Compared with 3D vintage OBC data imaging,3D DAS-VSP downgoing multiple imaging yields better results within a large area around the well bore;OBN and 3D DAS-VSP imaging yields better results for high-resolution structure interpretation and fluid detection.Owing to high efficiency and low cost of joint borehole-marine acquisition,it is possible to accomplish fast 3D DAS-VSP imaging and enhanced well-driven resolution processing of 3D marine seismic data.Besides,3D OBN or OBC data and 3D DAS-VSP data could be processed together for joint borehole-surface or borehole-marine migration to significantly improve the im-aging quality of 3D marine seismic data.

Abstract The optical fiber distributed acoustic sensing system can continuously detect acoustic signals along the optical fiber, with the characteristics of wide response frequency band, large capacity, anti-electromagnetic interference and so on. An ultra-sensitive distributed optical fiber acoustic sensing system (uDAS) was produced with a high response frequency up to 100 kHz and thousands of sensing points. The arrayed ultrasonic detection can be realized by the distributed characteristics of the system. For verifying its ultrasonic detection ability, it is applied to ultrasonic nondestructive testing of structural defects. 20 optical fiber ultrasonic detection units were constructed. Each one is a fiber ring with a diameter of about 1.5 cm and a length of 2 meters. Two cubic cement structures with a side length of 30 cm were manufactured for experiment, one of which had an artificial internal defect. The optical fiber array was attached to the surface of the cement structure, and the ultrasonic signal with a frequency of 40 kHz was excited at a single point on the opposite side. The ultrasonic propagation speed changes on account of the defects such as holes and loose texture in the propagation path. The defects in the structure are identified and located by analyzing the difference of arrival time of waves. It is expected that such sensing system could found important applications in structure defect detection.

近年来,光纤传感技术已经应用于地面地震数据、海洋地震数据、井中地震数据和井-地联合地震数据的采集,推动了光纤传感技术在地球物理特别是地震数据采集领域的应用.对国内外应用于陆地、海洋和井中的光纤地震数据采集系统进行了简要介绍,重点关注了分布式光纤声波传感(DAS)技术在井中地震数据和井-地联合地震数据的采集、处理和综合解释中的应用.光纤传感技术是一项革命性的新技术,光纤因体积小、不带电、分布式、高密度、多参量、耐高温、高压、全段接收和低成本等特征,必将带来井下、海洋和陆地地球物理技术的一场革命.井中分布式光纤声波传感技术已广泛应用于井中VSP数据采集、水力压裂微地震监测和精准工程监测,可实现油气井全生命周期监测、管理和使用.分布式光纤传感技术在油气资源勘探开发领域的规模化推广应用,已经从井中延伸到陆地和海洋;从井下单分量测量拓展到井下和陆地三分量测量(螺旋形绕制的铠装光缆);从单井单参数测量发展到了多井多参数同步测量,调制解调仪器也从单通道单参数发展到了多通道多参数复合调制解调系统.光纤传感技术应用已经由地震勘探领域延伸至油气藏开发领域,围绕光纤应用的地球物理技术对地下结构的静态刻画和动态永久监测逐步形成光纤油藏地球物理技术的基础.展望未来,分布式三分量光纤声波传感技术将在井中、陆地(沙漠)和海洋中用来替代常规三分量检波器采集高密度全波场三分量地震数据,可实现陆地、海洋和井下的高效率、低成本、高密度三分量地震数据采集.此外,研制开发集分布式光纤声波、温度、应变传感于一体的多分量、多参数、多通道复合调制解调仪器;开展耐高温、高瑞利散射系数、抗氢损和弯曲不敏感特种光纤的研制与批量生产;三分量分布式光纤声波(地震波)传感数据采集系统的研制;高密度分布式三分量光纤地震数据处理软件的开发;井-地三分量联采地震数据的联合偏移成像方法研究;套管外铠装光缆定位定向技术与设备研发和与之配套的定向射孔光缆避射技术的发展;人工智能技术在光纤传感领域的推广应用等,必将推动光纤地球物理技术的创新性发展,实现对整个油气田储层的光纤智能油藏感知、描述、模拟和监测,智能优化开发方案和生产制度,在未来智慧油气田的建设中发挥重要的技术支撑作用.

设计了一种超灵敏分布式声波传感地震仪(uDAS(R)),该仪器以高性能相敏型光时域反射仪为基本构架,利用多频和随机光纤激光放大技术,结合干涉解调方法,实现了瑞利散射光信号相位的精确解调,可用于外界声波/振动信号的高精度拾取.实验结果表明,uDAS(R)在1～500 Hz内噪声底达4.5pε√Hz,同时具有线性幅度响应、长距离工作等特征.与电子检波器进行对比测试,二者的记录波形高度一致.uDAS(R)已初步应用于井中地震监测、微测井等勘探作业,获得了高质量的生产资料.此外,uDAS(R)在长期动态监测、管线监测等油气勘探与开发等业务中具有巨大的应用前景.

针对油气藏评价、油气田开发与油气藏生产阶段提出的如何发现残余油和剩余油,如何提高采收率等问题,应用大规模布设的分布式传感光纤,采集井中地震数据,实时收集油气藏储层参数与油气井动态生产数据,进行智能化处理,实现油气藏智能描述、模拟和监测,优化调整油气藏的开发方案和发现剩余油气资源,最终达到提高油气藏采收率的终极目标.基于分布式光纤传感的油藏地球物理技术,将能够直接感知油气藏储层和油气生产井下声波、温度、压力、应变、流体类型等参数的铠装传感光缆布设到沿井孔或油气藏储层内水平井中,实现对整个油气藏的智能描述和监测.近几年中国石油集团东方地球物理勘探有限责任公司主导创新发展了基于分布式光纤声波传感技术的uDAS?地震仪及其配套的井中地震数据采集装备,大力推动光纤井中地震技术、光纤井中—地面联合立体勘探技术、水力压裂光纤微地震及精准储层改造工程监测技术、光纤井下长期动态监测技术在国内大部分油田的规模化推广应用,促进并引领了油藏地球物理光纤智能技术的跨越式创新发展.

A 3D surface seismic data acquisition project was conducted simultaneously with 3D DAS-VSP data acquisition in one well in Jilin Oilfield of Northen China. The 3D surface seismic data acquisition project covered an area of 75 km2, and one borehole (DS32-3) and an armoured optical cable with high temperature single mode fiber were used to acquire the 3D DAS-VSP data simultaneously when the crew was acquiring the 3D surface seismic data. The simultaneously acquired 3D DAS-VSP data were used to extract formation velocity, deconvolution operator, absorption, attenuation (Q value), anisotropy parameters (η, δ, ε) as wel as enhanced the surface seismic data processing including velocity model calibration and modification, static correction, deconvolution, demultiple processing, high frequency restoration, anisotropic migration, and Q-compensation or Q-migration. In this project, anisotropic migration, Q-migration was conducted with the anisotropy parameters (η, δ, ε) data volume and enhanced Q-field data volume obtained from the joint inversion of both the near surface 3D Q-field data volume from uphole data and the mid-deep layer Q-field data volume from all available VSP data in the 3D surface seismic surveey area. The anosotropic migration and Q-migration results show much sharper and focussed faults and and clearer subsutface structure.

Fiber-optic distributed acoustic sensing (DAS) technology has many outstanding advantages, such as long sensing range, high detection efficiency, wide frequency response, low operation cost, long working lifetime, et al. It can be anticipated that DAS has great potential to become a next generation technology of long-distance vibration and acoustic wave detection in the future. However, despite the rapid development of DAS technology, the sensitivity of optical cable is still a main limitation in terms of the applications of DAS technology. In this paper, we propose and demonstrate a sensitivity-enhanced optical cable with smaller diameter, lighter weight, and greater flexibility than conventional cables. This novel cable is experimentally tested both in lab and field. The results show that the acoustic sensitivity of the cable has been significantly improved by ~10 times, comparing with a rigid cable that has much higher reflection and attenuation of acoustic waves. Hence, such a sensitivity-enhanced cable could be one of the best candidates for DAS applications as a general sensing cable. In addition, we found that the experimental results are in agreement with our theoretical analysis, providing a guidance for design of sensitivity-enhanced cables. Finally, this cable has been successfully demonstrated in the field test of borehole vertical seismic profiling (VSP), and good performances have been achieved. The perfect combination of sensitivity-enhanced cables and high-performance DAS systems would provide a powerful tool for many DAS applications.

Distributed Fiber Optic Sensing is increasingly recognized as a viable alternative to geophone arrays for the acquisition of borehole seismic data. The ability to deploy optical fibers into a well, either as a cable based intervention or as part of a completion string, allows for the entire wellbore to be surveyed with every source activation. This can dramatically reduce the operating time required to complete a normal survey as well as offering the opportunity to achieve much higher spatial coverage than is typical of current technologies. The ability to acquire borehole seismic data in a producing well without the need to disrupt production also offers significant benefits to the operator. Distributed acoustic sensing (DAS) is a novel technology that uses an optical fiber cable as a sensor for acoustic signals and can take almost any downhole fiber-optic installation or deployment and turn the fiber optic cable into a large downhole seismic array. This array can provide enhanced Vertical Seismic Profile (VSP) imaging and monitor fluids and pressures changes in the hydrocarbon production reservoir. Walkaway VSP data acquired over a former producing well in north eastern China provided a rich set of very high quality DAS Walkaway VSP data. A standard VSP data pre-processing workflow was applied, followed by prestack Kirchhoff time migration. In the DAS pre-processing step we were faced with additional and special challenges: strong coherent noise due to cable slapping and ringing along the borehole casing. In comparison with an earlier offset VSP data set using 327-levels acquired with conventional 3C downhole geophones in the same well, the final preprocessed DAS walkaway VSP has a larger vertical aperture resulting in a wider lateral image. The single well DAS Walkaway VSP images provide a good result with higher vertical and lateral resolution than the surface seismic in the objective area. The vertical well environment without the ability to effectively "clamp" the sensor to the borehole casing wall by touching, creates a unique set of challenges. Although earth signal was recorded with almost all the shots, there was also a considerable amount of noise. Much of the noise was due to the physical placement of the wireline in the well and expressed by slapping and ringing. This paper reports on lessons learned in the handling of the wireline cable and subsequent special DAS data processing steps developed to remediate some of the practical wireline deployment issues. Optical wireline cable as a conveyance of fiber optic cables for VSP in vertical wells will open the use of the DAS system to much wider applications.

Most seismic data is processed to optimize image quality for structural and stratigraphic interpretation, with little regard to preserving characteristics essential for successful seismic reservoir characterization. No matter how sophisticated the inversion algorithm, use of inadequately processed seismic data will severely impact the quality of the final interpretation. The objective of this paper is to quantify the advantages of performing pre-stack data conditioning prior to reservoir characterization. Three specific seismic properties that will be addressed are: (1) signal-to-noise ratio (SNR), (2) off set-dependent frequency loss, and (3) gather alignment. Seismic gather conditioning improved seismic data quality prior to pre-stack inversion by improving signal/noise ratio, removing NMO stretch and aligning reflection events. Velocities from residual moveout (RMO) analysis on individual sectors were used as input to detection of fracture orientation and anisotropy. In all of our integrated studies, our goal is to offer the greatest understanding of the depositional environment, so that decisions can be made with confidence. This paper was withdrawn from the Technical Program. It was not presented at the 87th SEG Annual Meeting.

Summary An integrated study of the well Zhao-104 and surrounding wide-azimuth 3D seismic volume within the shale gas reservoir in South China has been conducted with the objective of generating shale formation properties related to fracture orientation and intensity in the area and deriving such reservoir rock properties as data quality allows. The inversion for P and S impedance and derivative attributes produced volumes that relate to rock properties such as brittleness and rigidity that are likely to impact fracturing. Seismic attribute analysis of anisotropy from elliptical velocity inversion indicates that anisotropy varies horizontally and vertically, and that it is dominantly controlled by stress azimuth, which conforms to the current day stress field as independently determined from borehole break-outs. At the end, the multi-attribute data fusion process to integrate all “sweet spot” parameters, such as shale formation depth, thickness, fault and fracture zone intensity and distribution, TOC and its thickness distribution, local stress field and its orientation, formation brittleness, pressure coefficient, impedance, Passion’s ratio, Young’s modules, porosity distribution, was used to predict “sweet spot” for shale gas reservoir exploration and production.

Distributed acoustic sensing (DAS) is a novel technology that uses an optical fiber cable as a sensor for acoustic signals and can take almost any downhole fiber-optic installation or deployment and turn the fiber-optic cable into a large downhole seismic array. This array can provide enhanced vertical seismic profile (VSP) imaging and monitor fluids and pressure changes in the hydrocarbon-production reservoir. Walkaway VSP data acquired over a formerly producing well in northeastern China provided a rich set of high-quality DAS walkaway VSP data. A standard VSP data preprocessing workflow was applied, followed by prestack Kirchhoff time migration. In the DAS preprocessing step, we were faced with additional challenges: strong coherent noise due to cable slapping and ringing along the borehole casing. Compared with an earlier offset VSP data set using 327 levels acquired with conventional 3C downhole geophones in the same well, the final preprocessed DAS walkaway VSP has a larger vertical aperture, resulting in a wider lateral image. The single-well DAS walkaway VSP images provide a good result with higher vertical and lateral resolution than the surface seismic in the objective area. The vertical-well environment, which lacks the ability to effectively “clamp” the sensor to the borehole-casing wall by touching, creates a unique set of challenges. Although earth signal was recorded with almost all the shots, there was also a considerable amount of noise. Much of the noise was due to the physical placement of the wireline in the well and was expressed by slapping and ringing. Reported here are lessons learned in handling the wireline cable and subsequent special DAS data processing steps developed to remediate some of the practical wireline deployment issues. Optical wireline cable as a conveyance of fiber-optic cables for VSP in vertical wells will open the use of the DAS system to wider applications.

ABSTRACTThe time‐invariant gain‐limit‐constrained inverse Q‐filter can control the numerical instability of the inverse Q‐filter, but it often suppresses the high frequencies at later times and reduces the seismic resolution. To improve the seismic resolution and obtain high‐quality seismic data, we propose a self‐adaptive approach to optimize the Q value for the inverse Q‐filter amplitude compensation. The optimized Q value is self‐adaptive to the cutoff frequency of the effective frequency band for the seismic data, the gain limit of the inverse Q‐filter amplitude compensation, the inverse Q‐filter amplitude compensation function, and the medium quality factor. In the processing of the inverse Q‐filter amplitude compensation, the optimized Q value, corresponding gain limit, and amplitude compensation function are used simultaneously; then, the energy in the effective frequency band for the seismic data can be recovered, and the seismic resolution can be enhanced at all times. Furthermore, the small gain limit or time‐variant bandpass filter after the inverse Q‐filter amplitude compensation is considered to control the signal‐to‐noise ratio, and the time‐variant bandpass filter is based on the cutoff frequency of the effective frequency band for the seismic data. Synthetic and real data examples demonstrate that the self‐adaptive approach for Q value optimization is efficient, and the inverse Q‐filter amplitude compensation with the optimized Q value produces high‐resolution and low‐noise seismic data.

Summary An integrated study of well Zhao-104 and surrounding wide-azimuth 3D seismic data volume within the shale gas reservoir in South China has been conducted with the objective of generating shale formation properties related to fracture orientation and intensity in the area and deriving such reservoir rock properties. Well data, structural seismic information and prestack inversion products were combined in an integrated interpretation. Seismic gather conditioning improved seismic data quality prior to prestack inversion by improving signal/noise ratio, removing NMO stretch and aligning reflection events. Fracture strike and P wave anisotropy were calculated using the RMO updated sector velocity fields in elliptical velocity inversion, while inversion for P and S impedance and derivative attributes produced volumes that relate to rock properties such as brittleness and rigidity that are likely to impact fracturing. The inversion for P and S impedance and derivative attributes produced volumes that relate to rock properties such as brittleness and rigidity that are likely to impact fracturing. Seismic attribute analysis of anisotropy from elliptical velocity inversion indicates that anisotropy varies horizontally and vertically, and that it is dominantly controlled by stress azimuth, which conforms to the current day stress field as independently determined from borehole break-outs.

The inverse Q-filter procedure attempts to eliminate the effect of the Earth Q-filter and hence improve the seismic resolution. The numerical instability of inverse Q-filter amplitude compensation reduces the SNR (signal-to-noise ratio) and limits the spatial resolution. Although the gain-limit constrained stable factor method can control the numerical instability and the SNR, but its gain-limit is time-invariant and is not associated with the seismic data; then it usually suppresses high frequencies at later times and reduces the seismic resolution. In this paper, we focus on understanding the impact of the gain-limit, the Q value and the dynamic range of seismic data to the seismic resolution, and propose a self-adaptive method for inverse Q-filter amplitude compensation. The gain-limit in the self-adaptive method is time-variant and self-adaptive to the cut-off frequency of the effective frequency band of seismic data; and the stabilizing factor changes in inverse proportion to the square of the self-adaptive gain-limit; then, the self-adaptive method can restore energy in the effective frequency band and control the numerical instability, and finally achieve high resolution and high SNR seismic data. Synthetic and real data examples demonstrate that the self-adaptive inverse Q-filter compensates for energy loss without boosting high frequency noise, and produces desirable seismic images with high resolution and high SNR.

The Earth Q-filter, with frequency-dependent amplitude attenuation and velocity dispersion, can distort seismic wavelet and reduce the seismic resolution. While the inverse Q-filter attempts to eliminate such effect and hence improve the seismic resolution. But the numerical instability of inverse Q-filter amplitude compensation can reduce the SNR (signal-to-noise ratio) and limit the spatial resolution. Although the gain-limit constrained cut-off frequency method and stable factor method for the inverse Q-filter can control the numerical instability and the SNR, in which the gain-limit is time-invariant and is not associated with the dynamic range of seismic data, it usually suppresses high frequencies at later time and reduces the seismic resolution. In order to solve this problem, we should fully compensate energy of seismic data in the effective frequency band and suppress noise beyond it.This work proposes a self-adaptive approach for inverse Q-filter amplitude compensation based on the cut-off frequency and stable factor methods. The gain-limit in this method is time-variant and self-adaptive to the cui-off frequency of the effective frequency band of seismic data; and the stabilizing factor changes in inverse proportion to the square of the self-adaptive gain-limit.The self-adaptive approach can restore energy of seismic data in the effective frequency band and control the numerical instability, and finally achieve high resolution and high SNR data. Synthetic and real data examples demonstrate that the self-adaptive inverse Q-filter can compensate for energy loss without boosting high frequency noise, and produce desirable seismic images with high quality.In order to achieve desirable resolution and high SNR of seismic data by the self-adaptive approach for inverse Q-filtering, the Q value and the cut-off frequency of the effective frequency band at any time should be relatively accurate.

PreviousNext No AccessSEG Technical Program Expanded Abstracts 2015Rock physics diagnostics and modeling for shale gas formation characterization in ChinaAuthors: Gang Yu*Yusheng ZhangXiming WangPaola NewtonIlgar AzizovGang Yu*BGP Inc., CNPC, P. R. ChinaSearch for more papers by this author, Yusheng ZhangBGP Inc., CNPC, P. R. ChinaSearch for more papers by this author, Ximing WangBGP Inc., CNPC, P. R. ChinaSearch for more papers by this author, Paola NewtonRSI, Houston, USASearch for more papers by this author, and Ilgar AzizovRSI, Houston, USA, ConocoPhillips, Houston, USASearch for more papers by this authorhttps://doi.org/10.1190/segam2015-5734796.1 SectionsSupplemental MaterialAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract Our study applied a geophysical well log analysis, rock physics diagnostics and rock physics modelling to an exploration well log data from a shale gas exploration area in the Sichuan Basin of South China. The study established an unconsolidated model (80% quartz plus 20% clay in the shale gas formation) transform between the acoustic and elastic impedance on the one hand and lithology, porosity, water saturation, clay content, quartz content, and TOC content on the other hand. Through our geophysical well log analysis, we calculated mineral volumes using best available data, total and effective porosity, water saturation, and bulk density and VS prediction where it was missing. For rock physics modeling, the shale gas formation matrix substitution (Clay, Quartz and TOC) and porosity modeling were performed in this exploration well. Crossplots are also used to analyze the elastic properties of the shale gas formation including VP velocity vs density, Acoustic Impedance (AI) vs total porosity (ΦT), AI vs Poisson's Ratio (PR), and VP vs VS. The results were quality controlled by core sample laboratory analysis data. To understand seismic effect as a result of rock physics modeling, ray traced synthetic modelling has been applied. The Ray-traced synthetics have been generated for the in situ and modeled scenarios for AVA analysis. These transforms will be upscaled and applied to acoustic and elastic impedance inversion volumes to map lithology, porosity, and TOC distribution in the shale gas exploration area. Keywords: shale gas, modeling, rock physics, reservoir characterizationPermalink: https://doi.org/10.1190/segam2015-5734796.1FiguresReferencesRelatedDetails SEG Technical Program Expanded Abstracts 2015ISSN (print):1052-3812 ISSN (online):1949-4645Copyright: 2015 Pages: 5634 publication data© 2015 Published in electronic format with permission by the Society of Exploration GeophysicistsPublisher:Society of Exploration Geophysicists HistoryPublished Online: 19 Aug 2015 CITATION INFORMATION Gang Yu*, Yusheng Zhang, Ximing Wang, Paola Newton, and Ilgar Azizov, (2015), "Rock physics diagnostics and modeling for shale gas formation characterization in China," SEG Technical Program Expanded Abstracts : 3031-3035. https://doi.org/10.1190/segam2015-5734796.1 Plain-Language Summary Keywordsshale gasmodelingrock physicsreservoir characterizationPDF DownloadLoading ...

Basing on the expression of amplitude attenuation and phase velocity dispersion proposed by Futterman, and considering the well-seismic matching, we derived the expression of seismic wave velocity dispersion between phase velocity and amplitude spectrum for the following four cases: without inverse Q-filter; with only inverse Q-filter amplitude compensation, with only inverse Q-filter phase compensation, with inverse Q-filter phase and amplitude compensation, and explained the necessity of inverse Q-filter phase compensation in theory. Through the zero-offset VSP data example of dynamite and vibroseis source with the same acquisition geometry, we verified the velocity dispersion expression derived in this paper. Through the example of well-seismic calibration, we further illustrated that inverse Q-filter phase compensation can effectively eliminate seismic wave velocity dispersion, enhance well-seismic matching, finally improve the reliability of surface seismic data.

The earth Q-filter, including the energy dissipation of high frequency wave components and the velocity dispersion, distorts seismic wavelets, reduces the seismic resolution, and causes difficulty to obtain high resolution seismic data. The process of inverse Q-filter attempts to remove the Q-effect to produce high-resolution seismic data, but the numerical instability of inverse Q-filter amplitude compensation reduces the signal-to-noise (S/N) ratio and limits its spatial resolution. In order to control the numerical instability, a large number of papers studying the gain-limit constrained inverse Q-filter amplitude compensation method. But, papers rarely discussing whether gain-limit constrained inverse Q-filter with the medium Q value can certainly improve the seismic data resolution or not, and what gain-limit and Q value should be used in inverse Q-filter in order to improve the resolution. In this paper, we focus on understanding the impact of Q value and gain-limit to seismic data resolution, and studying a novel method to optimize Q value within a certain gain-limit constrained inverse Q-filter amplitude compensation, by which we can achieve the optimum resolution seismic data.

Great progress has been made on VSP techniques in recent years, especially the improvement of downhole geophone manufacture and VSP data-processing methods. In XJWZ area of Daqing oil field, the reservoir is formed mainly by volcanics, and its distribution is complex because of many periods of volcanic overlap in the area. Early seismic surveys in the area had been mainly 2D and narrow-azimuth 3D, which are not suitable for anisotropy analysis and fracture identification. Therefore, a joint survey of 3D VSP and full-azimuth surface seismic was implemented. The project was an attempt to combine the advantages of VSP and surface seismic by 3D VSP and full-azimuth surface-seismic simultaneous survey. Q factor and anisotropy parameters estimated from VSP are applied to 3D seismic processing. Reservoir characterization and gas-saturation prediction with final images showed encouraging results. Suggested wells have been drilled and wet gas has been found, so the validity of this method has been proved.