【作者】 吴志强；

【导师】 李庆忠；

【作者基本信息】 中国海洋大学 ， 海洋地质， 2009， 博士

【摘要】 南黄海中-古生界碳酸盐岩油气勘探起步晚,针对性的地震勘探技术研究程度低,制约了该区油气勘探的进程。通过近几年对南黄海中部隆起海相地层的地震勘探攻关研究,主要从理论方法、正演模拟及关键勘探技术三个方法进行了研究。完成的主要工作包括:地震反射特征研究、海上采集技术研究与实践、多次波形成机理及压制技术研究、基于地震叠加速度的模拟及精细速度分析研究,以提高深层弱反射信号品质的关键处理技术研究与实践,形成了针对南黄海中部隆起中-古生界海相地层的地震勘探关键技术系列。通过攻关研究与实践,取得了如下4项创新及技术成果:1.建立了地震反射波特征综合模拟分析技术首次综合运用Zoeppritz方程、Snell定律和地震波在传播过程中的吸收衰减规律,全波波动方程和地震物理模型实验等技术方法,对地震反射波特征进行了理论计算、数值模拟和物理模拟等综合分析,总结了影响中-古生界海相地层地震反射波品质的主要因素,得出了长排列、高覆盖次数的地震采集参是获得高质量的海相深部地层有效地震反射信号资料的基础,正确的叠加速度是获得高品质剖面成果的关键。2.海上地震采集参数综合设计与评价技术研究分析了气枪、电缆不同沉放深度组合的子波特征参数与穿透力、传播距离的关系;提出了依据地震勘探目标,需综合考虑子波各特征参数、特别是能量、主频、最低保护频率、最高保护频率和子波波形等参数,才能选择准确适用的震源子波。采用理论研究与海上试验相结合的方式,进行了地震资料海上采集试验,验证了地震子波参数理论模拟的正确性,建立了针对南黄海海相地层地震勘探的采集参数系列,即长排列、高覆盖次数、较深的气枪和电缆沉放深度;得到了测线必须与构造走向平行或近似平行,才能获取品质好的深部反射的有效信号的结论。3.基于速度特征模拟的精细速度分析技术通过对测井速度资料理论计算分析,首次进行了地震速度、多次波机理等模拟分析,研究了速度突变、层间多次波条件下的叠加速度变化规律,分析了高速地层与多次波生成及二者对叠加速度的影响,发现了T2界面折射波速度分析,是确定地震叠加速度特征、地震反射品质和多次波发育程度的关键因素;提出了参考T2界面的折射波速度资料,指导地震速度分析的技术思路;建立了速度分析、多次波压制、DMO倾角校正循环迭代精细速度分析流程。4.突出深层弱反射信号的地震处理关键技术系列在分析了影响南黄海地震资料品质因素的基础上,通过技术方法研究、软件开发和处理试验,形成了针对南黄海中-古生界海相地层地震资料处理的关键技术。关键技术包括:层间多次波特征研究与识别、自行开发的高精度抛物线拉东变换的多次波压制技术、基于速度特征模拟的精细速度分析技术、深层弱反射能量综合提升及精确成像偏移技术。通过技术方法研究和科研生产实践,地震勘探效果显著。在中部隆起上首次获得了波组特征清晰、信噪比高的海相地层有效反射,实现地震勘探的突破,为南黄海海相地层油气地质前景研究提供了资料支撑。更多还原

【Abstract】 The exploration of carbonate hydrocarbon entrapped at Mesozoic—Palaeozoic depositing at South Yellow Sea started lately and corresponding seismic exploration technique development was poor, which prevented the development of seismic exploration.The remarkable improvement have been obtained on seismic exploration of marine stratigraphic depositing in the middle uplift of South Yellow Sea through resent studying on exploration theory, forward modeling and key prospecting techniques. The main studies included of seismic reflection research, maring acquisition technical research and practice, multiple mechanism and pressing research, modeling on seismic stacked velocity and fine velocity analysis and the key techniques applied to improve the poor quality of deep seismic reflection, as a result a series of techniques have been built applied to the exploration of marine stratigraphy depositing in Mesozoic—Palaeozoic in the middle uplift of South Yellow Sea.Four new innovations and techniques had been got through studying key project and making practices.1 The synthetic modeling techniques for analyzing seismic reflection charactersIt firstly used Zoeppritz function, Snell law and absorption attenuation regular of seismic wave propagating, full wave equation and seismic physical model experiment to make seismic reflection characteristics calculated theoretically, analogizing in digital and in physical, so the dominant factors controlling Mesozoic—Palaeozoic strata reflection had been summarized and it had been concluded that long layout and multiple coverage could be used to obtain better quality seismic acquisition data and correct stacked velocity could ensure improving the seismic section quality.2 The techniques for designing and evaluating marine seismic acquisition parametersThe relationship of wavelet character parameters, which was resulted from different optimum depth of air gun and streamer, dependent on penetrating power and propagation distance had been studied and analyzed. And then the every wavelet characters parameter, especially energy, dominant frequency, minimum safeguard frequency, maximum safeguard frequency and wavelet forms, should be considered according to different seismic prospect target to select suitable source wavelet.The acquisition parameters had been obtained for exploring marine stratigraphy through theory studying and marine testing to verify the theory modeling for seismic wavelet parameters correct. The parameters obtained were consisted by long layout, multiple coverage, deeper depth locating air gun and streamer. It had been resulted that the effective reflection could be acquired if the line was parallel or approximlately parallel to the trend of the structure.3 The technique for analyzing velocity basing on velocity character modelingThe seismic velocity and multiple mechanisms had been firstly modeled and analyzed through logging velocity calculation and analysis. The stacked velocity change regulars had been observed through studying abrupt velocity change and multiple generated in horizons. The high velocity formations and multiple generation and their effects on stacked velocity had been then analyzed to found that the refractions velocity induced at T2 interface is key for defining stacked velocity and reflection quality and multiple development. It was suggested that the T2 interface refraction velocity could be used to guide seismic velocity analysis. The workflow for velocity analysis, multiple pressing and DMO dip correction had been configured.4 The key processing technique for emphasizing deep poor reflection The factors influence on quality of seismic data acquired at Yellow South Sea had been analyzed. The key techniques for processing seismic data acquired at Mesozoic—Palaeozoic strata depositing at Yellow South Sea had been developed, which were consisted of multiple study and identification, multiple pressing developed by ourselves named high accuracy paracurve Radon transform, velocity analysis on velocity characters modeling, deep poor energy improvement and accurate imaging migration.The remarkable exploration improvement had been obtained through method study and production practice. The effective reflection from marine strata with clear wave group character and high ratio of signal to noise had firstly been acquired at the middle uplift, which had provided data base for marine strata hydrocarbon prospecting in Yellow South Sea.更多还原