库车坳陷依奇克里克构造带侏罗系阿合组沿东西方向埋深相差小于1 km,但储层物性、孔隙结构差异大.储层平均孔隙度相差3倍,渗透率至少相差一个数量级.自西向东,微孔隙有逐渐减少的趋势,粒间孔逐渐增加.研究区内构造应力对储层有重要的影响.通过自西向东选取迪北102井、依南5井、吐孜4井和吐东2井阿合组粗粒长石岩屑砂岩样品开展分析,探讨了一种既考虑岩石表观体积变化、又考虑杂基体积变化的模型来定量分析压实作用对储层的破坏程度.结合埋藏史分析和平衡剖面恢复,用深时指数和伸缩率参数开展回归分析,区分出横向挤压和垂向压实对储层的破坏程度,比较了构造挤压作用对储层孔隙空间的贡献率.研究结果表明:依奇克里克构造带自西向东阿合组储层的压实减孔率逐渐减小;构造挤压减孔在压实减孔中占比呈两侧高、中部低;构造裂缝对储层的改善程度远远小于构造挤压对储层的破坏程度.

The Keshen gas field is located in the central part of Kuqa foreland thrust belt in Tarim Basin, and is another large gas field discovered in Kuqa depression after Kela 2 gas field. Since the breakthrough in 2008, a number of large and medium scale gas reservoirs including Keshen 2, Keshen 5 and Keshen 8 have been discovered, that are characterized by ultra depth, ultra-high pressure, ultra-low porosity, ultra-low permeability, high temperature and high pressure. With natural gas geological reserves of nearly trillion cubic meters and production capacity of nearly 5.5 billion cubic meters, the Keshen gas field is the main natural gas producing area in Tarim Oilfield. The Keshen gas field is located in a series of thrusting imbrication structures in the Kelasu structural belt of Kuqa foreland thrust belt. The salt roof structure, plastic rheology of salt beds and pre-salt faulted anticlinal structure constitute the large wedge-shaped thrust body. The thick delta sandstone of the Cretaceous Bashijike Formation is widely distributed, and it forms the superior reservoir-caprock combination with overlying Paleogene thick gypsum-salt bed. The deep Jurassic-Triassic oil and gas migrate vertically along fault system formed in Late Himalaya, break through the thick Cretaceous mudstone and move laterally along the fracture system of the pre-salt reservoirs, to form anticline and fault anticline high pressure reservoir groups. Through near ten years of studies, the three-dimensional seismic acquisition and processing technology for complex mountainous areas, extrusion salt-related structural modeling technology and fractured low-porosity sandstone reservoir evaluation technology have been established, which lay a foundation for realization of oil and gas exploration objectives. Logging acquisition and evaluation technology for high temperature, high pressure, ultra-deep and low-porosity sandstone gas reservoirs, and efficient development technology for fractured tight sandstone gas reservoirs have been developed, which provide a technical support for efficient exploration & development and rapid production of the Keshen gas field.

库车坳陷复杂山地地表地下双重复杂、地表高差大、山体发育、沟壑纵横,古近系膏盐岩挤压变形严重,厚度变化大,盐上浅层高陡,盐下目的层逆冲叠瓦断块发育,导致地震资料信噪比低,成像效果较差.通过多年复杂山地地震资料处理研究,形成了起伏地表TTI各向异性叠前深度偏移技术.叠前深度偏移速度建模中,采用了小平滑基准面,通过微测井约束层析反演计算静校正厚度、时间和速度,建立较高精度的浅表层速度模型;综合应用地表露头、重磁电、地质和钻测井资料约束建立了合理的中深层速度模型;采用井控TTI各向异性参数提取及网格层析成像技术提高了速度模型和成像的精度.通过TTI各向异性叠前深度偏移处理,库车坳陷复杂山地地震资料信噪比和成像质量明显提高,为区带研究及圈闭落实奠定了基础.

克深三维地震区位于库车坳陷克拉苏构造带东部,其地表地形高陡,起伏剧烈,地下构造复杂,地震资料信噪比较低,叠前时间偏移处理后误差很大.为提高目的层成像质量,使断片接触关系更清楚,运用了叠前深度偏移处理.但受叠前深度偏移速度模型精度限制,利用叠前深度偏移确定的构造形态与实际存在一定差异.为了提高构造成图精度,提出了利用叠前深度偏移速度模型,将叠前深度偏移数据转换到时间域,即深时转换,同时开展岩相、地震相和应力相三相融合的速度分析,最终利用变速成图落实复杂圈闭.该方法继承了深度偏移资料归位较准确、三相融合速度场精度较高和变速成图技术成熟的优点,提高了圈闭落实精度.利用该成果部署的一批井位与实钻吻合程度显著提高,为克拉苏构造带山地三维地震区油气发现及整体评价勘探奠定了基础.

PreviousNext No AccessSEG/SINOPEC Foothill Technical Forum, Nanjing, China, 23-24 April 2017Challenges for Seismic Imaging in the Tarim BasinAuthors: Ning GuoHuiwen XieChao WuAnming XuZhiyong LiuZhibo MaNing GuoGeoTech Groups, LLC., Houston, Texas, 77027, USASearch for more papers by this author, Huiwen XieInstitute of Exploration and Development, PetroChina, Korla, 841000, ChinaSearch for more papers by this author, Chao WuInstitute of Exploration and Development, PetroChina, Korla, 841000, ChinaSearch for more papers by this author, Anming XuInstitute of Exploration and Development, PetroChina, Korla, 841000, ChinaSearch for more papers by this author, Zhiyong LiuBeijing Aoyier Engineering Technology Co. Ltd, Beijing, 100100, ChinaSearch for more papers by this author, and Zhibo MaBeijing Aoyier Engineering Technology Co. Ltd, Beijing, 100100, ChinaSearch for more papers by this authorhttps://doi.org/10.1190/Foothill2017-4 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract The Tarin Basin, Northwest, China, exhibits most of the difficulties for successful seismic imaging, including (i) rugged topography with outcrops of hard rock interbedded with weathered mud or loose sands; (ii) near-surface with weather sediments surrounding isolated conglomerates which are not seismically distinguishable; (iii) complex subsurface geology with two different depositions separated by plastic salt with variable velocities, and the land deposition usually has anisotropy and large structural dips resulting in strong lateral velocity changes, while the marine deposition is strongly compressed north-south wise making the target T8 layer a shingled structural style with very narrow extend. This article addresses the above problems, and searches for the solutions to them. Keywords: imaging, Asia, near surface, anisotropyPermalink: https://doi.org/10.1190/Foothill2017-4FiguresReferencesRelatedDetails SEG/SINOPEC Foothill Technical Forum, Nanjing, China, 23-24 April 2017ISSN (online):2159-6832Copyright: 2017 Pages: 29 publication data© 2017 Published in electronic format with permission by the Society of Exploration GeophysicistsPublisher:Society of Exploration Geophysicists HistoryPublished Online: 02 Jun 2017 CITATION INFORMATION Ning Guo, Huiwen Xie, Chao Wu, Anming Xu, Zhiyong Liu, and Zhibo Ma, (2017), "Challenges for Seismic Imaging in the Tarim Basin," SEG Global Meeting Abstracts : 13-16. https://doi.org/10.1190/Foothill2017-4 Plain-Language Summary KeywordsimagingAsianear surfaceanisotropyPDF DownloadLoading ...

Zero-offset VSP is based on the assumption of horizontal strata.For inclined layer,the time-depth relationship and seismic corridor stack of zero-offset VSP is not accurate,and more seriously,the imaging position on corridor stack record under observation well section is incorrect,so we need to conduct DMO correction.For complex high-steep structure,we propose a modified method of space varying DMO correction for zero-offset VSP data.Firstly,the down-going and up-going waves are used to calculate dip angle of reflection interface,an initial 2D interval velocity model is established.Then,by tracing down-going and up-going wave`s ray path with ray tracing algorithm,the above velocity model is amended,which can make the up-going waves of zero-offset VSP from complex high-steep structure come to flat.It not only enhances the accuracy of corridor stack record,but makes up-going wave correctly imaging under observation well section.Therefore,the accurate prediction of formation depth and seismic reflections characteristics are achieved.Time-depth relationship is also corrected to direct path wave travel time in vertical depth,which effectively resolves problems such as time-depth relationship,seismic horizon calibration and pre-drilling prediction in complex high-steep structure.The actual data processing shows the effectiveness of the method.

塔里木盆地库车坳陷北部油气资源丰富,但由于受研究区地表和地下构造双重复杂特征及巨厚膏盐层的影响,其深层地震资料的成像质量与精度不理想,准确研究盐下构造形态存在较大难度.为此,基于前人的研究成果,根据最新的三维叠前深度偏移地震剖面,建立了克拉苏构造带盐下构造层的初始构造模型,并运用面积深度法分析了盐下构造层的变形特征和变形机制.结果表明:①盐下层构造的分布以克拉苏断裂为界线,断裂以北主要发育基底卷入的高角度逆冲构造,而断裂以南则主要发育滑脱构造;②克拉苏断裂以南区域滑脱面的位置介于8.01～10.23 km深度,推测该滑脱层为三叠系与下伏基底之间的不整合面;③博孜区域的滑脱距离为7.49 km,大北区域的滑脱距离为14.35 km,克深5区域的滑脱距离为12.46 km,克深1-2区域的滑脱距离则为16.32 km,该区盐下构造层的滑脱距离呈现出自西向东逐渐增加的趋势,表明从西向东构造变形越来越强烈.

由于DB三维区古近系盐上浅层高陡,盐下目的层逆冲断片发育,导致地震资料品质差:信噪比低,成像不理想.无论是时间域处理还是各向同性叠前深度偏移处理,均难以得到好的成像,不能满足构造精细解释需要,限制了该区天然气勘探.为了提高地震资料品质,这里针对DB高陡构造低信噪比资料,除了处理解释一体化提高高速砾岩体速度建模精度外,重点开展了倾斜介质——TTI各向异性参数研究,获得了参数预测的有效方法.通过各向异性模型与速度模型的迭代,使得叠前深度偏移的速度模型更加合理,明显提高了地震资料成像质量.

基于地表露头调查、地震资料解释、钻井及与盐相关的构造样式分析,对库车坳陷中部构造变形特征进行研究。结果表明:库车坳陷中部具有南北分带、东西分段、垂向分层的变形特征。以库姆格列木群膏盐岩为界可以分为盐上构造层、盐构造层、盐下构造层及基底构造层4层结构。该区域主要发育收缩构造样式及盐构造样式,盐上构造层、盐构造层及盐下构造层的构造样式及分布具有明显差异。盐上层主要发育逆冲断层及褶皱,盐岩层则以盐流动构造样式为主,盐下层则发育逆冲叠瓦断层等大规模推覆构造。研究区具有明显的分段变形特征,可划分为博孜—却勒构造段、大北—西秋构造段、克深—西秋构造段、克拉3—东秋构造段,其差异性主要表现为地表线性褶皱带分布、盐构造样式、盐下构造变形的差异。区域构造演化剖面研究表明库车坳陷主要经历了中生代伸展坳陷盆地（三叠纪—白垩纪）、新生代早期"挠曲"盆地（古近纪—中新世）及新生代晚期前陆盆地（上新世—第四纪）的演化过程。现今构造主要形成于库车组沉积的中晚期。