【作者】 王林飞；

【导师】 刘怀山；

【作者基本信息】 中国海洋大学 ， 海洋地球物理学， 2009， 博士

【摘要】 近年来,随钻地震技术(Seismic While Drilling简称SWD)作为一种新兴的井中地震勘探技术,在国外迅速发展起来。它是利用钻井过程中钻头破岩产生的振动噪声为震源进行地震勘探,属于无源地震的范畴。随钻地震勘探,没有仪器设备下井风险,不干扰正常的钻井工作,不占用钻井时间,可以在钻井现场实时地采集、处理和解释随钻地震数据,能实现对井筒周围、钻头前方地层岩性和压力情况的实时预测,减少钻井风险,提高钻井勘探效率。因此,研究随钻地震勘探技术,具有极其重要的现实意义和发展前景。随钻地震技术是一项公认的世界性难题,发展至今仍然没有形成一套完善的采集方法及其相应的处理技术。国外的部分公司逐步实现了现场应用,而在国内随钻地震技术的研究相对较少,还处于起步阶段。本学位论文依托国家高新技术研究发展计划(863计划)课题“随钻地震(RVSP)技术研究”(课题编号:2006AA06A108),对随钻地震勘探的关键技术展开了较为系统的研究。本文在熟练掌握国内外随钻地震技术发展现状的基础上,全面分析了随钻地震基本原理,总结和论述了随钻地震数据采集方法与数据处理方法。针对目前传统随钻地震资料采集方法的缺陷,提出了随钻地震勘探最佳观测方式和随钻地震最佳波场分离技术,并应用于实际的随钻地震资料采集与数据处理,均取得了良好的勘探效果。本学位论文通过关键技术的科研与攻关,主要取得了以下新的突破与认识:⑴系统地研究了随钻地震波场理论,将随钻地震波场进一步划分为钻头波场、钻柱波场和地表(井场)波场,综合研究了它们的形成机理及传播规律,掌握了随钻地震波场的基本特征,初步探讨了随钻地震特殊干扰波的压制方法,为随钻地震最佳观测方式和最佳波场分离研究奠定了关键性的理论基础。⑵基于随钻地震波场特征,首次提出了随钻地震勘探最佳观测方式,解决了在井场强背景噪声下,如何准确采集钻头信号的关键性技术难题。利用流动地震仪阵列,在国内首次实现了高精度的、实时的、全天候的、长时间的连续采集随钻地震数据,突破了传统随钻地震数据采集方法不能长时间记录且采集精度不高的局限性,为实时监控井下作业状态、及时预测钻前地层及压力情况,提供了必要的技术条件,同时也为随钻地震波场能量的长时间积累提供了有效途径。建立了以流动地震仪实时采集为主,陆用压电检波器和10Hz常规检波器采集为辅的随钻地震观测模式,实现了连续井深的测量,完成了较深井段上随钻地震数据高精度的采集。⑶针对随钻地震波场的传播规律,首次提出了基于传播特性的随钻地震最佳波场分离方法,并进一步发展了随钻地震信号加强技术,解决了如何从井场强干扰噪声背景中准确提取与恢复弱的钻头信号的关键性技术难题。利用该方法分别对G130井和LS101井的地震数据进行了波场分离,成功地提取出清晰的钻头直达波。并利用所得结果进行了初步的钻前预测。⑷通过室内波场正演模拟,室内物理实验和现场实测数据的处理与分析,取得了良好的勘探效果。利用本文提出的随钻地震最佳观测方式和基于传播特性的随钻地震最佳波场分离方法,在国内外首次实现了较深井段上随钻地震钻头直达波地提取与恢复,说明上述新的采集与处理方法的正确性与可靠性,实现了理论与实践的有机结合。本文的研究成果对随钻地震勘探资料采集与数据处理具有建设性的指导意义和重要参考价值。更多还原

【Abstract】 In recent years, seismic while drilling (SWD) has rapidly developed, as a new downhole seismic technique. It uses the vibrations produced by a drill bit while drilling as a downhole seismic energy source, which makes it belong to passive seismic. Seismic while drilling surveys are acquired without any downhole instrumentation. It means there is no interruption to drilling, no lost rig time and no risk to the borehole while the seismic data are being acquired. These characteristics offer a method by which borehole seismic data can be acquired, processed and interpreted while drilling. Subsurface conditions ahead of the drill bit can be predicted at any time during drilling without tripping out of the hole and seismic data are available at the well site for real-time drill decisions. Furthermore, it can reduce the drilling risk and improve the efficiency of drilling. Therefore, it is very important and necessary to do research on the seismic exploration while drilling.As is known to all, the key technologies of seismic while drilling are very difficult to resolve. So far, there has been not an appropriate method of field acquisition and data processing of seismic exploration while drilling yet. Few companies have gradually tried practice application of the SWD technique at abroad. But there are few researchers to study this technique at home. It has just begun to study seismic while drilling techniques. Then this dissertation aims to research the key technologies of seismic while drilling and it is financially supported by the National High Technology Research and Development Program (863 program) of China (Grant No. 2006AA06A108). Mastery of the technical developments of seismic while drilling at home and abroad, this dissertation analyze the basic principle of seismic while drilling, systematically dissertated and summarized the acquisition method and the data processing of seismic while drilling. In view of the shortcomings of conventional acquisition method of SWD, this dissertation proposes the optimal survey mode and the optimal wavefield separation of SWD. And it is successful to apply these new techniques to the real SWD data acquisition and data processing. By tackling key problems, this dissertation achieves the following breakthrough and innovations:⑴This paper systematically study the SWD wavefield theory and obtain the characteristic of drill-bit wavefield, drill-string wavefield and surface (well site) noise wavefield of SWD. It provides the key theoretical foundation of the optimal survey mode and the optimal wavefield separation of SWD.⑵Based on the characteristic of SWD wavefield, this paper proposes the optimal survey mode of SWD, which settle the key problem of recording the drill-bit signal from the strong ambient noises at well site exactly. By the array of portable seismometer, this survey mode achieve the high- precision, all-day-and-night, long-time, continuous acquisition of real SWD data at home for the first time, which overcomes the shortcomings of traditional method。It not only provides the necessary technical condition for real-time prediction ahead of the drill bit, but also provide an effective approach for long-time energy accumulation。Additionally, this paper proposes that the SWD field acquisition is mainly achieved by seismometers. Conventional land receivers can be used as supplementary sensor. By the optimal survey mode, SWD data of deep vertical well is recorded exactly.⑶Considering the propagation laws of SWD wavefield, this paper proposes the optimal wavefield separation of SWD for the first time, which is based on the characteristics of the SWD wavefield. It resolves the key problem of extracting the drill-bit signal from the strong ambient noises at well site exactly. It is successful to extract the direct arrival from SWD data in G130 well and Ls101 well, by means of the new technique. Also the results can be used for simply predicting ahead of drill bit.⑷Forward modeling of SWD wavefield, drill-bit physical experiment as well as data processing and analyzing of real SWD data, obtain better results. It justifies the validity of this paper proposed optimal survey mode and optimal wavefield separation of SWD and integrates theory with practice.The results and production in this dissertation has instructional meaning and important referenced values for the further study of SWD.更多还原