-
海上风电工程物探勘察主要目的是获取风场详细地质数据,构建清晰工程地质模型,从而分析预判可能地质灾害和确定潜在的施工危险。结合工程地质模型,物探勘察获取的高分辨率多波束测深和旁测声纳数据可识别沉船,磁力梯度仪数据可识别不明爆炸物(UXO),浅层剖面、电火花和高分辨率多道地震数据可识别浅层气和复杂地层,三维电火花和超高分辨率地震数据可识别埋藏孤石和局部砂体。图2显示某风电场海底表面的人工鱼礁。物探设备一致性分析研究是减少物探方法的多解性和确保清晰明确工程地质模型的关键和重要手段。
-
海洋工程物探包括多种调查方法和设备。对每一个工程物探设备,特别是水深测量设备都须遵循设定程序进行一致性标定,在一个给定已知点对设备和搭载平台进行多次测试,即静态校正。其目的是效验船只和设备的参数。标定结束后,设备还需通过自身的交叉走航测试对设备在搭载平台不同姿态进行实际验证,即动态校正。例如,应用广泛的多波束,动态校正还旨在解决设备和其相关外部传感器的一致性。通过重复收集和处理一些特定数据,多波束传感器的横摇和纵倾以及延迟和偏航等细微的偏差将能够被修正,达到一致性效果。图3显示一致性校正后,多波束数据精度得到提高。一致性校正前,特别是横摇,不同测线之间的数据互为噪音。
多波束一致性校正应按“时延—横摇—纵倾—艏向偏差”的顺序进行,且在进行下一个参数校正时要先输入已校正好的值,以排除校正时其他参数的影响。为保证测量的精度,每组校正至少需进行3次,按规范要求,经多次测量后标准误差应满足:定位时延±100 ms;横摇偏差±0.1°;纵倾偏差±0.1°;艏向偏差±0.1°[29],如果是浅水多波束要求更严格[30]。校正应在每个地勘项目数据采集前进行,如在野外作业过程中,船体有明显改变、换能器或涌浪补偿仪位移、测线间重合不好时,应重新进行参数的一致性校准。为便于不同测线数据间的比对,检验区域的海床应具有一定的坡度、地貌特征或水下沉船以增加辨识度(表1)。另外需要指出的是原始测试和采集数据应充分保存、备份和管理,测试结果应输入到工程地质模型中,便于查证和从新校正。
表 1 多波束一致性校正类别和要求
Table 1. Types and requirements of multi-beam consistency correction
类别 线长/m 海底地形特征 测线特征 航行速度/方向 一致性分析目的 定位时延 500~1 000 海底地形坡度
(10°~30°)同线、同向 船速相差1倍以上 消除船速对测量的影响 横摇偏差 500~100 平坦海底 同线、反向 相同船速 消除仪器横向倾角对测量的影响 纵倾偏差 500~1 000 海底地形坡度
(10°~30°)同线、反向 相同船速 消除仪器纵向倾斜对测量的影响 艏向偏差 500~100 斜坡或其他特征地形 不同线(线距大于最大条带宽带)、反向 相同船速 消除仪器安装艏向偏差对测量的影响 -
工程物探技术方法多样,但其目的都是通过获取的数据资料来查明工程地质模型,即海床地形地貌特征、地层变化、地质构造及其展布规律等地质情况(BOEM2014,2015)。在考虑不同设备方法在空间或频率局限性的同时,也应充分认识到不同方法对同一地质模型的测量结果应具有一致性。以声学为例,多波束测深设备是了解水深变化和海床地形、地貌特征等地质模型表层的主要技术手段,相对单波束测深,具有测量范围大、高精度、高密度和高效率的特点。系统已实现浅水到深水的全海域水深测量,其中用于海上风电的浅水多波束系统测量精度达5 cm(图3)。多波束测深主要工作频率在10 kHz的深水系统到400 kHz浅水系统范围内,由于超高的频率,声波基本没有穿透能力,不能反应地质模型海床以下的地层信息(表2)。浅层剖面测量是利用声波穿过不同的地层时存在界面反射特性来反映地质模型属性。应用比较广泛的浅地层剖面仪主频约为1.4~4.5 kHz;穿透深度通常在20~30 m;垂向分辨率最高可达0.1 m[31]。海床是浅层剖面的第一层反射界面,对比多波束和浅层剖面,虽然是两个频率不同的设备,但通过时声转化后得到的浅剖深度数据应与多波束一致,例如图4显示两者的横向一致性在1 m内、垂向一致性在0.15 m内。
表 2 地勘声波设备主要勘探参数
Table 2. Main exploration parameters of acoustic equipment for geological exploration
方法 用途 主频 垂直分辨率 穿透深度 多波束 海底地形地貌 200 kHz n/a 10 cm 浅层剖面 管线,基础调查,
风场场址勘察1.4~4.5 kHz <0.3 m 30 m 高分辨地震 地质灾害,
风场场址勘察150 Hz <3 m <1 500 m 常规地震 油气勘探 30 Hz <10 m >3 000 m 相对浅层剖面,单道和小道距高分辨地震测量的频率更低,能探测到更深的地层,主要用于了解工程地质模型的地层厚度、层序与结构构造以及构造运动等,成本相对传统油气多道地震要小,分辨率高。电火花震源多用于单道而单枪震源多用于高分辨率地震,两者能量小,波长短,具有分辨率高,拖拽便利,无汽包效应干扰等优点,但缺点是缺少多次覆盖,信噪比低。传统多道地震测量排列长、道间距大、海上施工复杂,通常适用于海底千米深度以下深层探测,用于探测深部地层、地质构造等;目前用于多道地震勘探基本采用多枪阵,气枪震源能量大穿透能力强。电火花数据能了解多道地震了解不到的地质模型信息,也能了解到多道地震能了解到的信息,反之亦然。因此,在工程地质模型中的多道数据应与电火花数据有一致的结果且互为补充。多设备一致性分析,不仅仅是数据间的相互验证,提高探测效果,增强对地质模型的刻画,更是弥补单一数据的多解性和数据采集的缺失。图5用沉积相一致性分析解释对比了某风场地勘中3种声波方法过同一测线的3个剖面,图5(a)为高分辨地震结果。高分辨地震可以识别出两个典型沉积相,揭示地质模型的3次海进海退沉积事件。第1套地震相以波状结构、中-低振幅、低-不连续、局部杂乱反射为特征,反映1个水动力较强、复杂的滨海-浅海相沉积环境。第2套沉积相以平行结构、中-强振幅、中-高连续为主要特征(图5(a)中的黑框和图6)。由于地震结果横向变化不大,纵向上分辨率低,此时,根据地震数据推断的地质模型较为模糊,强振幅代表沉积物粒度较粗、以强振幅为主要依据可推测该地沉积相为海平面相对下降以及陆源供应充足的三角洲陆地沉积环境;而中-高连续通常反映的是一个相对稳定的沉积低能环境,以中-高连续为主可推测该沉积相为海平面相对上升的浅海相沉积。因此,单一设备不能完全清晰刻画工程地质模型,也无法满足海风精准地勘生产需求。
图 5 工程地质模型3次海进海退一致性分析及电火花数据缺失
Figure 5. Consistency analysis of three marine transgressions and regressions in the engineering geological model, and data missing of electric spark
图 6 高分辨地震、电火花和Boomer振幅和连续一致性分析
Figure 6. Amplitude and continuity consistency analysis of high-resolution earthquake, electrical spark, and boomer
图5(b)为电火花剖面结果,其频率和采样率远大于高分辨地震(表2)。明显看出横向和纵向分辨率大幅提高。在第2套沉积相内,电火花更进一步清晰的显示地质模型薄层砂岩的边界和砂泥互层,确认了地震数据可靠性并解决了单一方法的多解性问题。电火花数据连续一致性分析显示第2套沉积相内夹杂低振幅、低连续反射,显示局部沉积物混杂堆积,不像是一个相对稳定的沉积环境,如图6所示。图5(c)为Boomer剖面结果,对比图5(a)和图5(b)可见,3次海进海退沉积事件分布几乎完全一致,且浅层薄砂体的可辨识性在Boomer剖面上得到提高,砂体横向不连续性更加明显。Boomer数据显示第2套沉积相内夹杂低振幅、不连续局部杂乱反射,底部边界清楚,显示三角洲陆地沉积环境、陆海交界较强冲刷的特征(图6)。因此,高分辨地震、电火花和Boomer振幅一致性分析支持陆相沉积环境解释,而地震相连续一致分析也支持路相沉积环境(图6)。同时,不同物探方法之间的交叉验证可以有效减小单一测试方法可能出现的系统误差。在电火花数据出现的海底麻坑、在地震和浅剖上并没有体现,表明麻坑为假象。电火花在此处的数据有丢失(图5)。
Research on the Engineering Geological Model and Its Application for Offshore Wind Power Development and Construction
-
摘要:
目的 加快海上风电建设和发展对促进我国能源结构调整具有重要意义,我国正迎来全海域海上风电开发浪潮,而地勘是海风开发的重要基础和关键技术。 方法 通过研究国内外海洋地勘技术并结合多年不同海域工作经验,提出一种基于一致性原则的海风工程地质模型新技术。首先,勘察设备选定及测线布置应从三维初始模型出发,评估地质变化和地面灾害对海风设计施工的影响,并充分考虑船只选型、野外原位和室内实验测试、物探和土工数据关联。然后,在可研和详勘阶段,获取钻孔及风场全区域丰富且连续的数据后,采用室内土工试验和原位测试相结合,多物探设备结合,岩土和物探方法相结合的方式对各种数据进行一致性分析、地勘数据平台管理、模型升级和建立最终模型,并在后续阶段不断优化和迭代工程地质模型。工程地质模型为海上风电场设计,安装,运维和退役全生命周期提供全面工程地质信息。 结果 研究结果和海风地勘实例表明,通过一致性综合布设和数据分析,有效连接岩土勘察和工程物探,构建立体交叉的工程地质模型能有效解决“地勘数据说不清”问题,提高地勘数据可靠性、精准性和应用度。 结论 所提新方法是海工实现降本增效的有效方法之一,也是海风地勘数字孪生的雏形和构建地勘大数据基因库的基础。 Abstract:Introduction Speeding up the offshore wind power construction and development is of great significance to promoting the adjustment of China's energy structure. China is accelerating the process of its wind power development in the entire offshore area, and the geological survey is a vital foundation and key technology of offshore wind power development. Method By studying the marine geological survey technologies at home and abroad and combining years of experience in different sea areas, this paper proposed a new technology of engineering geological modeling for offshore wind power development based on the principle of consistency. Firstly, the survey equipment selection and survey line layout started from a three-dimensional initial model to evaluate the impact of geological changes and geohazards on the offshore wind power engineering construction and took into full account the ship selection, field in situ and laboratory tests, and correlation of geophysical prospecting and geotechnical data. Then, with abundant and continuous data obtained from the boreholes and the whole wind farm during the feasibility study and detailed survey, the methods of combination of indoor geotechnical tests with the in-situ tests, the combination of multiple geophysical prospecting devices and the combination of geotechnical and geophysical prospecting methods were used to conduct a consistency analysis of various data, manage the geological survey data platform, update the model and build the final model, and the engineering geological model was continuously optimized and iterated in the subsequent stages. The engineering geological model provided comprehensive engineering geological information for the entire life cycle of offshore wind farm design, installation, operation, maintenance and decommissioning. Result The research results and offshore wind power geological survey examples show that by conducting consistent comprehensive layout and data analysis, effectively connecting geotechnical investigation with engineering geophysical prospecting and constructing a three-dimensional crossing engineering geological model, it can effectively solve the problem of "ambiguities of geological survey data" and improve the reliability, accuracy and application of geological survey data. Conclusion The new method proposed is one of the effective methods to reduce cost and increase efficiency in offshore engineering as well as the embryonic form of digital twin of offshore wind power geological survey and the foundation for the construction of a geological survey big data base. -
表 1 多波束一致性校正类别和要求
Tab. 1. Types and requirements of multi-beam consistency correction
类别 线长/m 海底地形特征 测线特征 航行速度/方向 一致性分析目的 定位时延 500~1 000 海底地形坡度
(10°~30°)同线、同向 船速相差1倍以上 消除船速对测量的影响 横摇偏差 500~100 平坦海底 同线、反向 相同船速 消除仪器横向倾角对测量的影响 纵倾偏差 500~1 000 海底地形坡度
(10°~30°)同线、反向 相同船速 消除仪器纵向倾斜对测量的影响 艏向偏差 500~100 斜坡或其他特征地形 不同线(线距大于最大条带宽带)、反向 相同船速 消除仪器安装艏向偏差对测量的影响 表 2 地勘声波设备主要勘探参数
Tab. 2. Main exploration parameters of acoustic equipment for geological exploration
方法 用途 主频 垂直分辨率 穿透深度 多波束 海底地形地貌 200 kHz n/a 10 cm 浅层剖面 管线,基础调查,
风场场址勘察1.4~4.5 kHz <0.3 m 30 m 高分辨地震 地质灾害,
风场场址勘察150 Hz <3 m <1 500 m 常规地震 油气勘探 30 Hz <10 m >3 000 m -
[1] 国家可再生能源中心.中国风电发展路线图2050(2014版)[EB/OL].(2018-03-04)[2022-10-10]. https://www.docin.com/p-2088144276.html. National Renewable Energy Center. China wind power development roadmap 2050 (2014 edition). [EB/OL]. (2018-03-04)[2022-10-10]. https://www.docin.com/p-2088144276.html [2] PEARCE S D, KILSBY C, KING F J, et al. Efficient design and execution of site investigations for offshore wind farms: learning from experience [J/OL]. (2019-05-06)[2022-10-10]. https://xueshu.baidu.com/usercenter/paper/show?paperid=0313a8ba2e3b528b49a507bce60d8f47. [3] OSIG. Guidance notes for the planning and execution of geophysical and geotechnical ground investigation for offshore renewable energy developments[R]. [S.l.]: Society for underwater technology, 2014. [4] 单治钢, 孙淼军, 王振红, 等. 海上风电重大工程地质问题与对策研究[C]//中国地质学会. 2021年全国工程地质学术年会, 山东: 青岛, 2021-10-14. 北京: 科学出版社, 2021: 210-219. DOI:10.26914/c.cnkihy.2021.038051. SHAN Z G, SUN M J, WANG Z H, et al. Research on major geological issues and countermeasures for offshore wind power projects [C]//Geological Society of China. 2021 national engineering geology annual conference, Shandong: Qingdao, October 14, 2021. Beijing: Science press, 2021: 210-219. DOI:10.26914/c.cnkihy.2021.038051. [5] 孟祥梅, 阚光明, 李官保, 等. 南黄海中西部海底空间沉积特征及工程地质特性 [J]. 工程地质学报, 2015, 23(6): 1202-1210. DOI: 10.13544/j.cnki.jeg.2015.06.023. MENG X M, KAN G M, LI G B, et al. Submarine spatial sedimentary characteristics and engineering geological features in the central-western south yellow sea [J]. Journal of engineering geology, 2015, 23(6): 1202-1210. DOI: 10.13544/j.cnki.jeg.2015.06.023. [6] 国家能源局科学技术部. "十四五"能源领域科技创新规划[EB/OL].(2022-04-03)[2022-10-10]. https://www.gov.cn/zhengce/zhengceku/2022-04/03/5683361/files/489a4522c1da4a7d88c4194c6b4a0933.pdf. Science and Technology Department, National Energy Administration. "14th Five-Year Plan" for technological innovation in the energy sector[EB/OL]. (2022-04-03) [2022-10-10]. https://www.gov.cn/zhengce/zhengceku/2022-04/03/5683361/files/489a4522c1da4a7d88c4194c6b4a0933.pdf. [7] 金飞, 叶晓冬, 马斐, 等. 海上风电工程全生命周期数字孪生解决方案 [J]. 水利规划与设计, 2021(10): 135-139. DOI: 10.3969/j.issn.1672-2469.2021.10.028. JIN F, YE X D, MA F, et al. Digital twin solution for the full life cycle of offshore wind power projects [J]. Water resources planning and design, 2021(10): 135-139. DOI: 10.3969/j.issn.1672-2469.2021.10.028. [8] 梁昆, 苏实. 基于LCOE最优的数字化风电场及其关键技术研究 [J]. 能源研究与信息, 2020, 36(4): 201-205. DOI: 10.13259/j.cnki.eri.2020.04.003. LIANG K, SU S. Research on digital wind farms and key technologies based on LCOE optimization [J]. Energy research and information, 2020, 36(4): 201-205. DOI: 10.13259/j.cnki.eri.2020.04.003. [9] 王一新, 王家林, 万明浩, 等.石油综合地球物理方法与应用 [M].北京: 石油工业出版社,1995 WANG Y X, WANG J L, WAN M H, et al. Comprehensive petroleum geophysical methods and applications [M]. Beijing: Petroleum Industry Press, 1995. [10] 李典庆, 唐小松. 水工岩土工程可靠度与风险控制领域基础研究回顾与展望 [J]. 中国科学基金, 2021, 35(3): 440-450. DOI: 10.16262/j.cnki.1000-8217.20210611.010. LI D Q, TANG X S. Review and prospect of basic research in the field of reliability and risk mitigation in hydraulic geotechnical engineering [J]. China science foundation, 2021, 35(3): 440-450. DOI: 10.16262/j.cnki.1000-8217.20210611.010. [11] CAI L, ZHU Y Y. The challenges of data quality and data quality assessment in the big data era[EB/OL]. (2015-05-22)[2022-10-12]. http://doi.org/10.5334/dsj-2015-002. [12] FENZA G, GALLO M, LOIA V, et al. Data set quality in machine learning: consistency measure based on group decision making[EB/OL]. (2021-04-07)[2022-10-12]. https://www.sciencedirect.com/science/article/abs/pii/S1568494621002891?via%3Dihub. [13] NEJATI A, RAVANSHADNIA M, SADEH E. Selecting an appropriate express railway pavement system using VIKOR multi-criteria decision making model [J]. Civil engineering journal, 2018, 4(5): 1104. DOI: 10.28991/cej-0309160. [14] CHENG J, CUI Z, HUANG W, et al. Learning data consistency and its application to dynamic MR imaging [J]. IEEE transactions on medical imaging, 2021, 40(11): 40-53. DOI: 10.1109/tmi.2021.3096232. [15] ERIC Z. Learning experience: ground conditions for offshore wind farms[EB/OL]. (2014-08-21)[2022-10-12]. https://www.newcivilengineer.com/archive/learning-experience-ground-conditions-for-offshore-wind-farms-21-08-2014/. [16] MORGENSTERN N R, CRUDEN D M. Description and classification of geotechnical complexities [R]. Capri Italy: International symposium on the geotechnics of structurally complex formations, 1977. [17] KNILL S J. Core values: the first hans-Cloos lecture [J]. Australian geomechanics, 2002(5): 37. DOI: 10.1007/s10064-002-0187-9. [18] DNVGL-RP-C212. Offshore soil mechanics and geotechnical engineering [S]. [S. l.]: [s. n.], 2021. [19] THOMAS S. A. Phased and integrated data interpretation approach to site characterization [C]// Offshore Site Investigation Geotechnics 8th International Conference Proceeding. Society for Underwater Technology, London, September 12, 2017, 71(87): 71-87. DOI: 10.3723/OSIG17.071. [20] REYNOLDS J M, CATT L M L, SALAÜN G, et al. Integration of geophysical, geological and geotechnical data for offshore wind farms–east anglia one owf, southern north sea, a case history [C]// Offshore Site Investigation Geotechnics 8th International Conference Proceeding. Society for Underwater Technology, London, September 12, 2017, 30: 1291-1298. DOI: 10.3723/OSIG17.1291. [21] OH K Y, Nam W, RYU M S, et al. A review of foundations of offshore wind energy convertors: current status and future perspectives [J]. Renewable and sustainable energy reviews, 2018, 88: 16-36. DOI: 10.1016/J.RSER.2018.02.005. [22] ZHANG Z, DIGBY A. Analysis of amplitude, reflection strength, and acoustic impedance of AUV sub-bottom profiles with application to deepwater near-surface sediments [C]// Anon. Offshore Technology Conference, houston, Texas, May 6, 2013. DOI: 10.4043/23978-MS. [23] PARRY S, BAYNES F J, CULSHAW M G, et al. Engineering geological models: an introduction: IAEG commission 25 [J]. Bulletin of engineering geology and the environment, 2014, 73(3): 707. DOI: 10.1007/s10064-014-0614-8. [24] RUSHTON D, NGUYEN M. On the application and benefits of an integrated geophysical and geotechnical digital ground model to optimize a site investigation survey for an offshore wind farm project. in: duc long, p., dung, n. (eds) geotechnics for sustainable infrastructure development [R]. Springer, Singapore:[s. n.], 2020: 1337-1344. DOI:10.1007/978-981-15-2184-3_175. [25] 牛海峰, 李向辉, 梁峰, 等. 海洋地勘黏土数据一致性原则及应用研究 [J]. 南方能源建设, 2023, 10(1): 124-132. DOI: 10.16516/j.gedi.issn2095-8676.2023.01.016. NIU H F, LI X H, LIANG F, et al. Research on consistency principles and applications of marine geotechnical data [J]. Southern energy construction, 2023, 10(1): 124-132. DOI: 10.16516/j.gedi.issn2095-8676.2023.01.016. [26] ASTM. Standard test method for electronic friction cone and piezocone penetration testing of soils, ASTM D5778-12 [S]. West Conshohocken: ASTM International. 2012. [27] MAYNE P W. In-situ test calibrations for evaluating soil parameters, characterization & engineering properties of natural soils [J]. Taylor & francis group, 2007, 3: 1602-1652. DOI: 10.1201/noe0415426916.ch2. [28] LADD C C, FOOTT R. New design procedures for stability of soft clays [J]. Journal of geotechnical engineering division, 1974, 100(7): 763-786. DOI: 10.1016/0148-9062(75)91177-8. [29] 中国地质调查局.中国地质调查局地质调查技术标准——海洋多波束测量规程: DD2012—01[S].北京:中国标准出版社2012 China Geological Survey. Technical standards for geological survey of China geological survey bureau: regulations for marine multibeam survey: DD2012—01 [S]. Beijing: China Geological Survey, 2012. [30] 上海市计量协会. 团体标准——沉管隧道多波束水下地形检测标准: T/SMA 0020—2021[S]. 上海: 上海交大海科检测技术有限公司, 2021 Shanghai Metrology Association. Group standard: standards for multibeam submarine terrain detection in immersed tube tunnels : T/SMA 0020—2021[S]. Shanghai: Shanghai Jiao Haike Testing Technology Co., Ltd., 2021. [31] ZHANG Z, DIGBY A J, GHARIB J J, et al. Analysis and interpretation of high-resolution geophysical data: offshore sarawak, south China sea[C]// Anon. Offshore technology conference, Houston, Texas,April 30, 2012. DOI: 10.4043/23155-MS.