高分辨率抛物线拉冬变换多次波压制技术

对于孔径过小,采样不充分的地震数据,抛物线拉冬变换的多次波压制效果不理想,且存在空间假频问题。综合Sacchi、Mauricio、Todd Mojesky等对抛物线拉冬变换压制多次波的分析,阐明了高分辨率抛物线拉冬变换原理。通过理论模型试验和实际地震数据的分析证明,高分辨率抛物线拉冬变换可以突破离散采样和有限孔径的限制,实现对地震数据中的多次波及空间假频的快速、有效压制。     

КОПЫТОВ递减开发模型

西方提出了Копытов递减开发模型,提出了开发速度,采出程度等开发指标的数学关系式。分析了参数对Копытов递减开发模型的影响,提出了开发初期Копытов递减开发模型的确定方法,便于开发初期决策。制作了Копытов递减开发模型的ｌｏｇＶＤ－ｌｏｇＲｐ图版,ｌｏｇＶＤ－ｌｏｇ（ｔ／ｃ）图版,ｌｏｇＲｐ－ｌｏｇ（ｔ／ｃ）图版。     

Parabolic Approximation of the Weakly Nonlinear Mild Slope Equation with Bottom Friction

This paper presents a refined parabolic approximation model of the mild slope equation to simu-late the combination of water wave refraction and diffraction in the large coastal region.The bottom frictionand weakly nonlinear term are included in the model.The difference equation is established with the Crank-Nicolson scheme.The numerical test shows that some numerical prediction results will be inaccurate in com-plicated topography without considering weak nonlinearity;the bottom friction will make wave height damp-ing and it can not be neglected for calculation of wave field in large areas.     

快速3D抛物Radon变换地震数据保幅重建

为解决3D AVO地震数据快速保幅重建问题,在传统3D抛物Radon变换的基础上提出一种3D快速高阶抛物Radon变换方法.该方法将传统抛物Radon变换与正交多项式相结合,通过正交多项式系数描述地震数据AVO信息,确保重建后的地震数据具有良好保幅效果.同时,该方法引入新变量λ_x=q_xf和λ_y=q_yf,通过对q_xf和q_yf的整体采样,消除了3D高阶抛物Radon变换算子对频率的依赖,使变换算子的求逆过程仅需计算一次,大大节省计算时间.理论模型和实际地震资料的处理结果表明,该方法重建效率高,保幅效果良好.     

Investigation of borehole effects on azimuthal resistivity measurements using novel pseudo-analytic formulas

Downhole resistivity measurements provide valuable information for geosteering and formation evaluation. It is important to understand and correct the environmental effects, such as the borehole, the tool eccentricity and the resistivity anisotropy effects, of the measurements based on fast and accurate modelling methods. A new pseudo-analytic solution for eccentric coaxial and tilted-coil antennas in the cylindrically multilayered medium with transverse isotropic conductivity was developed. This method can take the eccentric tool, the borehole, the mud invasion and the resistivity anisotropy into account. These formulas enable us to simulate the responses of the downhole induction logging tools, including induction wireline and azimuthal propagation logging-while-drilling measurements. Instead of using the prior fictitious boundary, the generalized reflection coefficients are proposed to construct the linear matrix functions to deal with the tool eccentricity. The cylindrical functions are reorganized and presented in forms of ratios. Thus, the proposed formulas obviate the overflow issue in the computation and are more stable and efficient. The proposed approach is compared and validated with other well-established methods. Simulations and case studies show that: (1) the responses of azimuthal resistivity logging-while-drilling tool are affected by the tool's eccentricity in both isotropic and anisotropic medium; (2) sine curve behaviours exist for the phase difference and amplitude ratio of azimuthal resistivity measurements along with different eccentricity azimuth.     

台风“天秤”对两种深海声道下声传播的影响

将Argo浮标资料与卫星遥感再分析数据相结合,调用基于抛物方程算法的RAM(Range-dependent Acoustic Model)模型,研究了2012年第14号台风“天秤”对不完整深海声道(3 000 m)和完整深海声道(5 500 m)两种水深条件下声传播特性的影响。结果显示:台风对海水的影响局限于表层水体,具体为混合层加厚,混合层内温度梯度接近于零,声速在混合层内正梯度分布;混合层下方一定深度的水体增温,相应的声速也增大。声源在混合层内时,主要对海表层的声传播产生影响,两种水深条件下均出现表面波导声传播模式以及泄漏模式。声源在混合层以下时,不完整深海声道条件下台风使得会聚区向着声源方向靠近;完整深海声道条件下台风对会聚区的位置影响不明显,但声波的翻转深度增加近500 m。     

表面多次波衰减的研究现状与进展

表面多次波是一种相干干扰,在海洋地球物理勘探中表面多次波尤为明显.本文给出了表面多次波衰减方法的研究现状的系统阐述,并分析了表面多次波衰减研究的发展趋势.表面多次波衰减主要有滤波法和波动理论方法.对于滤波法给出了广泛应用的抛物Radon变换法的实例,指出了抛物Radon 变换法存在滤波时能量泄漏的问题.同时本文分析了基于波动理论的处理优势和存在的问题,该方法可以处理任意介质的情形,但是对于数据的采集要求比较严格,另外在进行表面多次波衰减处理以前,要进行一系列的预处理,这些预处理的误差直接决定着多次波衰减的效果.最后,本文给出了表面多次波衰减的发展趋势——将滤波法和波动理论法结合来实现多次波的衰减.两类方法如何有效地结合是该类方法一个重要的研究方向.