四川盆地茅口组缝洞型储层预测技术研究

发布时间：2018-06-03 15:05

本文选题：四川盆地 + 茅口组　；参考：《成都理工大学》2017年硕士论文

【摘要】：针对缝洞预测这一世界性难题,从缝洞油气藏勘探方法研究的现状出发,开展精细目标处理及储层预测,寻找缝洞系统,为气藏的深化勘探开发提供较明确的勘探目标,建立了一套缝洞储层综合预测与评价的有效方法技术。本文中,将该套方法技术应用于四川盆地蜀南地区茅口组缝洞油气藏的勘探实践,预测有利勘探区,取得了以下新的认识和成果:(1)通过模型正演认为,当茅口组顶面存在缝洞系统的,反射波振幅会减弱,形成弱振幅,当茅口组层间有比较发育的缝洞时(往往会充填气、水或其他物质),缝洞体与周围介质存在较大的速度、密度和波阻抗差异,将会形成强反射,尤其是出现“短轴状、强波谷”地震响应特征。通过多属性分析,总结出茅口组溶蚀缝洞型储层发育段具有“低频强波谷”特征。(2)在分析了缝洞系统的地震响应特征和物理模型的基础上,建立了地震非线性整体反演(速度范围在5000m/s~5900m/s之间)预测技术,经过研究区共计31口井检验,所预测的储层速度与区内钻井一致,速度反演剖面上可以比较清楚地看到茅三段~茅二段的高速灰岩以及茅一段的低速泥页岩的分布,确定出茅口组储层缝洞方向和展布特征,取得很好地质效果。因此,该技术为解决缝洞预测难题提供了新的技术支撑。(3)频变AVO属性反演技术是基于Chapman理论,以同一地震资料不同子波主频的叠前地震道数据分别进行频变AVO属性反演,反演得到各自的截距、梯度、泊松比等AVO属性。将不同频率下反演得到的相同属性进行比值运算,获取该属性在频率变化时随之变化的变化强弱,由于溶洞的速度往往比盖层低很多,同时这里的衰减也变得比较厉害,因此高频部分衰减得比较多,而剩下能量较强的低频部分,横向上往往强于相邻区域。泊松比能反映岩性的变化,溶洞的地方泊松比的变化较大。本文选取低频的泊松比AVO属性进行溶洞识别,把检测结果与实钻测试情况对比后认为:基于频变AVO属性反演技术的油气检测技术效果较好。这种反演技术是缝洞预测的最佳估计方法,是缝洞定量预测技术,是缝洞预测的一种核心技术。通过对测井特征、模型正演、地震属性、反演速度、频变AVO属性的试验研究进行系统分析,建立了一套茅口组缝洞系统地震预测技术。使用该预测技术,开展了蜀南地区LNT构造气藏勘探开发目标评价,划分了有利地区,取得了很好的地质效果。其应用研究成果表明,该方法与技术研究成果均可适应不同类型缝洞系统的复杂多变性。
[Abstract]:In view of the worldwide difficult problem of fracture and cave prediction, starting from the present situation of the research on the exploration methods of fracture-cave oil and gas reservoirs, the fine target processing and reservoir prediction are carried out to find the fracture and cave system, which provides a clear exploration target for the further exploration and development of gas reservoirs. A set of effective methods and techniques for comprehensive prediction and evaluation of fractured-cavity reservoirs are established. In this paper, the technique is applied to the exploration practice of fracture hole reservoir in Maokou formation in Sichuan Basin, and the favorable exploration area is predicted. When there is a fissure and cavity system on the top surface of the Maokou formation, the amplitude of the reflection wave will weaken and form a weak amplitude. When there are relatively developed cracks and cavities between the layers of the Maokou formation (often filled with gas, water or other substances), there is a larger velocity between the seam and the surrounding media. The difference of density and wave impedance will result in strong reflection, especially the "short axis, strong trough" seismic response. Through multi-attribute analysis, it is concluded that the developed segment of the solution fracture-cavity reservoir of Maokou formation has the characteristics of "low frequency strong wave valley". (2) based on the analysis of seismic response characteristics and physical model of fracture and cavity system, The prediction technique of seismic nonlinear global inversion (velocity range is between 5000m/s~5900m/s) is established. A total of 31 wells are tested in the study area. The predicted reservoir velocity is consistent with that of drilling in the region. From the velocity inversion section, the distribution of high speed limestone and low velocity shale of Maoyi formation can be clearly seen, and the direction and distribution of fracture and cavity of Maokou formation reservoir can be determined, and good geological results can be obtained. Therefore, this technique provides a new technical support for solving the difficult problem of crack and cave prediction. The frequency variant AVO attribute inversion technique is based on the Chapman theory. The prestack seismic trace data with different wavelet frequencies from the same seismic data are used for the frequency variant AVO attribute inversion respectively. The AVO attributes, such as intercept, gradient and Poisson's ratio, are obtained by inversion. By calculating the ratio of the same attribute obtained by inversion at different frequencies, we can get the magnitude of the change of the attribute when the frequency changes. Because the velocity of the cavern is often much lower than that of the caprock, the attenuation here becomes more severe. Therefore, the high frequency part attenuates more, while the low frequency part with strong energy tends to be stronger than the adjacent region laterally. Poisson's ratio can reflect the change of lithology. In this paper, Poisson's ratio (AVO) attribute of low frequency is selected to identify caverns, and the result is compared with that of real drilling test. It is concluded that the oil and gas detection technology based on frequency-varying AVO attribute inversion technique is effective. This inversion technique is the best estimation method for the prediction of fractures and cavities, is the quantitative prediction technique of the fractures and cavities, and is a core technique for the prediction of the fractures and cavities. A set of seismic prediction techniques for the Maokou formation fracture-cavity system is established through systematic analysis of the experimental research on logging characteristics, model forward modeling, seismic attributes, inversion velocity and frequency-varying AVO attributes. Using this prediction technique, the target evaluation of exploration and development of LNT structural gas reservoirs in southern Shunan area has been carried out, and favorable areas have been divided, and good geological results have been obtained. The application results show that both the method and the technique can adapt to the complex variability of different types of fracture and cavity systems.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13

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