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海相碳酸盐岩储层地震响应特征数值模拟
Numerical Simulation of Seismic Response Characteristics of Marine Facies Carbonate Reservoir
【作者】 刘文革;
【作者基本信息】 成都理工大学 , 地球探测与信息技术, 2008, 博士
【摘要】 碳酸盐岩在我国分布广泛,如今塔里木盆地、四川盆地以及珠江口盆地已成为我国碳酸盐岩油气勘探的重点地区。随着碳酸盐岩油气勘探技术的提高,已取得轮南、塔中、靖边、罗家寨、千米桥等地区的油气发现和突破。碳酸盐岩隐蔽油气藏勘探由于储层空间分布的非规则性、多尺度性及勘探技术分辨率的限制,在勘探过程中仍然存在诸多困难。鉴于问题的复杂性,目前对储层还难以进行有效识别和预测。针对勘探难点,本文用数值模拟方法研究储层在地震记录上的响应特征规律,研究成果对储层识别和预测具有很高的应用价值和实际意义。本次研究工作主要集中在以下几个方面:1.实现复杂模型的高精度数值模拟。本文首先对单程波数值模拟傅立叶有限差分法、频率-空间域法、相移插值法及广义屏法进行理论推导和分析,对传统相移插值法给予修正并提出频率-空间域自适应插值方法,并对傅立叶有限差分法的发展潜力给予分析。通过标准模型试算,证明文中所述算法对于复杂模型能得到高精度数值模拟结果但相互间存在差异,并就算法计算精度及计算效率问题给出定量分析,为成像算法的实际应用提供参考。2.对实际资料典型碳酸盐岩储层地震响应特征进行数值模拟研究。首先用数值方法模拟碳酸盐岩理论缝、洞、礁等储集体在不同激发频率、地质条件下的地震记录,总结其运动学、动力学地震响应特征规律,通过实际资料处理证明利用数值模拟技术研究碳酸盐岩储层的可行性和有效性,研究储层地震响应特征有利于对碳酸盐岩储层进行识别。3.实现三维环礁模型的数值模拟研究。目前对碳酸盐岩油气藏数值模拟及属性参数研究大多只在二维情况下开展,而实际地下地质体却是三维的。本文通过综合建模技术建立三维环礁模型,并利用适应速度空间变化的三维数值模拟方法研究环礁的地震响应特征,且开发的软件已在微机上实现,具有实际应用前景。4.通过数值模拟研究地震波经过含流体储层后的高频吸收衰减现象,并利用低频响应特征对储层进行识别和预测。通过频率-空间域吸收补偿模型分析,给出在特定地震地质条件下对地震波吸收衰减进行高频补偿所应具备的条件,并在塔里木盆地塔中地区实际资料应用中有效提高地震数据体的垂向分辨率。
【Abstract】 Carbonate rocks are widespread in China, Now Tarim basin, Sichuan basin and Pearl River Mouth basin are becoming important regions for carbonate exploration. With development of technology, reservoir exploration has made great discoveries and outbreak at areas of Lungu, Tazhong, Jingbian, Luojiazhai and Qianmiqiao. There are still full of difficulties in the course of exploration because carbonate reservoir are unconventional, irregular, multi-scale space distribution and restrictions of limited spatial resolution. For the complication of the problem, it is hard to make the precise results using the ordinary reservoir identification and prediction technique. The paper has researched the character of seismic response by numerical simulation. The result is valuable for reservoir exploration. The achievements and recognitions are as follows:1. The paper has proposed high accuracy simulating methods for complex geologic model. Firstly methods based on one-way wave equation are discussed such as Fourier finite-difference, methods in the domain of frequency-space, phase shift plus interpolation and general screen propogators, and then propose adaptive interpolation method and point out the potential development of Fourier finite-difference. Accuracy numerical results on the standard data are achieved by these methods while exist discrepancy respectively, finally analyse the accuracy and efficiency quantificationally, it can be used for application as a reference.2. The paper deals with seismic simulating record. Firstly summarize the character ofseismic response of ideal model on fracture and reef by high-precision simulating method, and prove farther the availability for simulating making use of field seismic data processing, it is in favor of identification fracture.3. Seismic response of 3D dimension ring reef model is simulated. Currently carbonate reservoir and attribute parameter are studied almost in 2D while genuine geologic body is 3D. Now reef model is created by integrative structural modeling, and research the character of seismic response by imaging method which is steady for variational reference slowness, Software is programmed and implemented in personal computer and can be used widely in reality.4. Simulating wave propagation in the stratum filling with saturated liquid is studied. Reservoir can be forecasted using the character of high frequency absorption and attenuation. The effectiveness of compensation for high frequency in f-x domain is proved, and the applying situation of the seismic and geology in surface has been given which attenuation of high frequency of seismic wave ban be compensated by numerical simulations. The frequency band of post stack seismic data processed is widened properly and the temporal resolution is increased efficiently without decreasing the S-N ratio in Tazhong area of Tarim basin.
【Key words】 Carbonate; One-way wave; Seismic modeling; Fracture; Reef;