应用三分量浅层地震反射方法探测隐伏活动断裂

多波多分量地震勘探方法在油气田勘探开发中日益受到重视,但在工程和活动断裂探测中过去还没有开展多波多分量地震勘探的先例.本文简要介绍了在北京黄庄—高丽营断裂上开展的三分量浅层地震反射试验数据采集和资料处理方法,以及取得的初步结果.试验结果表明,采用纵波震源或横波震源激发、三分量接收的浅层地震勘探方法,可获得较高信噪比的浅层地震纵波、横波和转换波剖面,特别是水平分量采集的横波和转换波可提供很有意义的地下结构和构造信息.综合利用纵波、横波和转换波剖面特征进行的地质分层和断层解释结果取得了与跨断层的钻孔联合地质剖面结果较好的一致性.     

转换型折射波传播规律及其在转换波静校正中的应用研究

纵波震源激发、三分量检波器接收的三分量地震勘探技术是解决复杂油气藏勘探的有效手段.在三分量地震勘探资料处理中,转换波资料处理尤为关键,转换波资料处理的难点之一是转换波静校正.研究了非转换型折射波和转换型折射波传播规律,发现形成PPS转换型折射波的有利条件是上覆介质横波速度比下伏介质横波速度要小很多,提出了基于PPS转换型折射波的转换波静校正方法,并对实际三分量地震资料进行了处理,转换波静校正取得了较好的效果.     

三分量数字检波器在ZY油田应用效果分析

在水平分量的炮集记录中,数字三分量检波器直达波的椭圆率明显呈现出线性偏振的形态,并具有较高的分辨率,而模拟三分量检波器直达波的线性偏振不清晰,抗干扰能力差.在频谱分析和能量曲线分析的对比中,数字检波器的性能也高于模拟检波器.在PP波弱波阻抗界面的沙河组沙三12段,PS波表现出强反射界面,而且构造幅度比PP波剖面明显.在PS波剖面上,剖面深处两边的构造联系清晰可见,而在PP波剖面上很难解释剖面两边构造之间的关系,表明PS波资料对深层界面的成像能力有时不比PP波能力差,多分量资料在构造勘探上具有互补性.在沙四层底钻遇气层的马62井和马11井的测线CDP位置上,PP波和PS波的振幅比剖面上表现出低振幅比异常区,与钻井结果吻合.用多分量衰减系数或衰减比剖面,能够识别砂岩含气/水产生所产生的高频衰减异常.多分量地震属性及其比值剖面是储层含气异常指示的有效参数.     

内蒙古准苏吉花铜钼矿区三分量地震试验研究

三分量地震技术在能源勘探中发挥了重要作用,并取得了明显的地质效果.在金属矿勘探中,三分量地震的效果如何,有助于解决什么样的地质问题,还未曾开展过这方面的试验研究.为探讨三分量地震技术在金属矿勘查中的探测效果,我们在对内蒙古准苏吉花铜钼矿区钻孔岩心标本进行密度和速度测试的基础上,开展了三分量地震试验研究.试验采用炸药震源激发,单个正交28 Hz三分量检波器接收,多次覆盖的工作方法.通过对三分量地震数据进行处理,获得了能够用于解释的纵波和转换波地震剖面.分析纵波和转换波地震剖面能够看出,纵波剖面上的波组特征更明显,转换波剖面上的信息量更大,把两者进行综合解释,有利于金属矿地震资料的解释.利用所获得岩矿石弹性参数和地质资料,对获得的试验地震剖面进行了解释,根据试验剖面上的地震波组特征,认为在该8勘探线地质剖面以外NE一侧,有可能寻找到深部隐伏金属矿.     

利用叠前Kirchhoff积分偏移识别小断裂与低幅度构造

利用常规地震剖面精细解释小断层和低幅度构造存在较大困难.本文利用纵波和横波速度模型对采集得到的二维地震数据进行叠前Kirchhoff积分偏移得到纵波和转换横波深度和时间剖面,根据不同分量的深度和时间剖面联合解释小断层与低构造.深度剖面克服了时间剖面受地层厚度和地层速度共同制约的缺点,有利于识别低幅度构造.纵波（P）剖面与转换横波（PS）剖面相比有利于识别层间小断裂.我们对准噶尔盆地实际地震资料的处理和解释证实了这些优点.     

共炮检距二维弹性波地震剖面的偏移方法

共均匀各向同性介质的分界面上入射纵波时，除产生纵波反射Ｐ－Ｐ波外，还会产生转换横波的反射Ｐ－ＳＶ波。同样，当入射波为ＳＶ横波时，在分界面上会同时产生ＳＶ－ＳＶ反射波和ＳＶ－Ｐ反射转换波。对这种二维弹性波地震记录如何进行偏移是探讨的问题。为了能够处理实际地震数据，本文提出在共炮检距剖面上进行二维弹性波记录的偏移方法。     

川西凹陷孝泉地区3D3C量地震资料采集方法

川西坳陷孝泉地区深层须家河组致密砂岩气藏属于典型非常规裂缝性气藏,储层识别、裂缝检测、含气性识别是气藏研究的重点和难点.转换波3D3C勘探可同时获得反映岩石骨架和各向异性特性的C波资料及反映骨架及流体特性的P波资料,因而适用于川西孝泉深层超致密裂缝性气藏.在3D3C地震勘探中,三维三分量地震采集方法是采集到高质量多分量原始资料的技术保障,本文重点研究这种采集方法.首先根据地球物理参数,结合地质任务要求,分析了三维三分量观测系统设计的方法及观测系统参数,然后根据分析结果和勘探目的层的实际情况设计了同时适合纵波勘探和转换波勘探的面元尺寸、最大和最小炮检距、接收线距、束间滚动距等参数并确定了三维三分量观测系统.该观测系统在孝泉地区资料采集中,获得的三分量资料波组特征清楚,同相轴连续,反射信息丰富;Z分量剖面和R分量剖面反射层次清楚,目的层反射特征明显,具有非常好的构造形态一致性.     

多波高斯束叠前深度偏移速度分析(英文)

多分量地震资料叠前深度偏移技术可以对地下复杂地质构造进行更准确的成像,精确成像的前提是获取准确的纵横波偏移速度。本文采用高斯束偏移方法对多波地震数据进行偏移速度分析,首先分别给出纵波和转换波共偏移距域高斯束叠前深度偏移方法原理,在此基础上抽取纵波和转换波偏移距域共成像点道集;然后根据共成像点道集拉平准则,分别对纵波和横波速度进行更新;当两种波成像深度不一致时,对纵波和转换波成像剖面进行深度匹配,完成高精度的纵横波偏移速度分析。模型数据和实际资料试算表明,该方法是一种有效的多波偏移速度分析方法。     

陆上纵波源VSP资料中的纯横波

常规陆上VSP(Vertical Seismic Profiling)勘探普遍采用纵波震源激发,三分量检波器接收,主要利用的是纵波和转换横波信息。已有的研究表明,炸药震源在井下激发、可控震源在地面垂向振动,均会产生较强的纯纵波和一定强度的纯横波;泊松比差别较大的分界面有利于形成较强的透射转换横波。本文通过对激发形成的纯横波和下行转换形成的横波进行对比分析,认为纯横波的主频往往低于纯纵波的主频,而下行转换横波的主频通常接近纵波的主频。本文分别对两个陆上纵波源零偏和非零偏VSP资料进行分析,结果表明这些资料中普遍存在纯横波,只是横波的强弱存在不同程度的变化。利用纵波源零偏VSP资料,可以获得横波速度信。最后对VSP纵波和横波联合应用前景进行了分析,应该充分利用纵波源VSP资料中的横波信息。     

共炮检距二维弹性波地震剖面的偏移方法

在均匀各向同性介质的分界面上入射纵波时，除产生纵波反射Ｐ－Ｐ波外，还会产生转换横波的反射Ｐ－ＳＶ波。同样，当入射波为ＳＶ横波时，在分界面上会同时产生ＳＶ－ＳＶ反射波和ＳＶ－Ｐ反射转换波，对这种二维弹性波地震记录如何进行偏移是正在探讨的问题。为了能够处理实际地震数据，本文提出在共炮检距剖面上进行二维弹性波记录的偏移方法。具体做法是，首先用弹性波方程将两分量的地震记录分解为Ｐ－Ｐ（或ＳＶ－ＳＶ）波和Ｐ－ＳＶ（或ＳＶ－Ｐ）波，然后用我们已导出的适合于处理共炮检距剖面的叠前偏移方法对它们进行处理。用模拟数据进行的试验说明方法正确，效果良好。     

转换波四参数速度分析方法在k71地区的应用

3-D converted-wave data were acquired using digital MEMS （micro-electromechanical system） three component （3C） sensors in the alternating sand and shale sequence in the overburden of the Shengli Ken-71 area. This gives rise to serious non-hyperbolic moveout effects in the converted-wave data due to both the asymmetrical ray path and anisotropic effects. Conventional velocity analysis and moveout correction based on isotropic methods do not flatten reflections events. Here, we use a four-parameter theory to evaluate these effects and process the data. These four parameters include the PS converted wave stacking velocity （Vc2）, the vertical velocity ratio （Y0）, the effective velocity ratio （Yeff）, and the anisotropy parameter （xoff）, The method utilizes the moveout information at different offsets to estimate the different parameters and ensures that the events are properly aligned for stacking, As a result, this four-parameter theory leads to an improvement in imaging quality and correlation between the P-waves and converted-waves.     

Propagation characteristics of converted refracted wave and its application in static correction of converted wave

Three-component seismic exploration through P-wave source and three-component geophone is an effective technique used in complicated reservoir exploration. In three-component seismic exploration data processing,one of the difficulties is static correction of converted wave. This paper analyzes propagation characteristics of non-converted and converted refracted waves,and discovers a favor-able condition for the formation of converted refracted wave,i.e. the velocity of overlaying medium S wave is much lower than that of underlying medium S wave. In addition,the paper proposes the static correction method of converted wave based on PPS converted refracted wave,and processes the real three-component seismic data with better results of static correction of converted wave.     

井间高分辨率纵横波层析成像研究井间油藏

采用视速度-偏振井间波场分离法分离得到纵波和横波波场,使用跨孔地震走时层析成像级联方法计算井间纵波和横波速度结构以及泊松比空间分布.综合纵横波速度、泊松比和测井参数,分析两井间岩性和储层特性.数值模型试验表明该方法垂直分辨率达到主频波长的1/4,并能准确分辨倾斜断层和垂直断层.处理相同纵波资料结果表明本文方法分辨率远远高于以往的井间走时层析成像方法,比井间声波层析成像分辨率更高.使用该方法处理垦71区井间资料,得到同台同源纵波和横波速度结构和泊松比分布.泊松比的低/高变化与测井参数指示的砂/泥岩层基本吻合.根据泊松比分布,参考岩石地震物理学测试数据,可以区分井间介质中的泥岩层、砂岩层,以及砂岩层中的饱水和饱油区,确定储层的连通性,圈定井间的剩余油藏.     

Geophone-seabed coupling effect and its correction

By summing geophone and hydrophone data with opposite polarity responses to water layer reverberation, the ocean bottom cable dual-sensor acquisition technique can effectively eliminate reverberation, broaden the frequency bandwidth, and improve both the resolution and fidelity of the seismic data. It is thus widely used in industry. However, it is difficult to ensure good coupling of the geophones with the seabed because of the impact of ocean flow, seafloor topography, and field operations; therefore, geophone data are seriously affected by the transfer function of the geophone-seabed coupling system. As a result, geophone data frequently have low signal-to-noise ratios (S/N), which causes large differences in amplitude, frequency, and phases between geophone and hydrophone data that severely affect dual-sensor summation. In contrast, the hydrophone detects changes in brine pressure and has no coupling issues with the seabed; thus, hydrophone data always have good S/N. First, in this paper, the mathematical expression of the transfer function between geophone and seabed is presented. Second, the transfer function of the geophone-seabed is estimated using hydrophone data as reference traces, and finally, the coupling correction based on the estimated transfer function is implemented. Using this processing, the amplitude and phase differences between geophone and hydrophone data are removed, and the S/N of the geophone data are improved. Synthetic and real data examples then show that our method is feasible and practical.     

Research and application of spectral inversion technique in frequency domain to improve resolution of converted PS-wave

Multi-wave exploration is an effective means for improving precision in the exploration and development of complex oil and gas reservoirs that are dense and have low permeability. However, converted wave data is characterized by a low signal-to-noise ratio and low resolution, because the conventional deconvolution technology is easily affected by the frequency range limits, and there is limited scope for improving its resolution. The spectral inversion techniques is used to identify λ/8 thin layers and its breakthrough regarding band range limits has greatly improved the seismic resolution. The difficulty associated with this technology is how to use the stable inversion algorithm to obtain a high-precision reflection coefficient, and then to use this reflection coefficient to reconstruct broadband data for processing. In this paper, we focus on how to improve the vertical resolution of the converted PS-wave for multi-wave data processing. Based on previous research, we propose a least squares inversion algorithm with a total variation constraint, in which we uses the total variance as a priori information to solve under-determined problems, thereby improving the accuracy and stability of the inversion. Here, we simulate the Gaussian fitting amplitude spectrum to obtain broadband wavelet data, which we then process to obtain a higher resolution converted wave. We successfully apply the proposed inversion technology in the processing of high-resolution data from the Penglai region to obtain higher resolution converted wave data, which we then verify in a theoretical test. Improving the resolution of converted PS-wave data will provide more accurate data for subsequent velocity inversion and the extraction of reservoir reflection information.     

地震勘探中检波器组合特性研究

本文基于组合的基本原理和方法,分析了两种情况下检波器组合问题.以前在这方面做的研究分析工作很少,但实际上它对地震资料的分辨率影响很大.通过模型计算,从组合后的频率特性曲线上,可以看出在不同的地形条件下,检波器组合个数、检波器间距对地震资料质量和分辨率以及精度有很大的影响.     

Using Four-Component Geophones: Effect on the Quality and Reliability of Multicomponent Seismic Recording and Analysis of Processing Methods

For seismic observations in mines or wells, instead of three-component geophones, four-component ones with sensors located along the tetrahedral axes are sometimes used. When a geophone is placed in a hard-to-reach area for a long time, the requirements on its reliability increase, so it is necessary to monitor its operation. From this viewpoint, a four-component geophone has certain advantages over the conventional three-component geophone, the three ones being suppression of instrument noise for the recalculation of a four-component record into a three-component one, saving of the polarization analysis data in case one geophone component fails, and sensitivity control of individual geophone components. To suppress instrument noise in records from a four-component geophone, the following processing should be performed: first, calculation of the covariance matrix of recording components, second calculation of the eigenvalues and eigenvectors of the covariance matrix, and third, the parameter used to assess the ratio of instrument noise to the useful signal is calculated. After that, the operator projecting a four-component displacement vector onto a three-dimensional subspace is constructed. Application of this operator to data suppresses interference or noise (which do not correspond to motion in three-dimensional space). The output of the processing is data partially cleaned of instrument noise. In this paper, using model examples, we analyze the features of processing data from four-component geophones. The possibility of suppressing instrument noise and controlling the sensitivities of individual geophone components is demonstrated, and the effect on polarization analysis results is shown.