南海东部某油田低伏构造速度建场研究

发布时间：2018-03-07 16:27

本文选题：低幅度构造　切入点：钙质预测　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：对速度的研究一直以来都是地球物理研究的重中之重,速度建场方法的精度直接影响到构造成图的精度,影响圈闭落实,产量分析及区域的经济价值评估。精确的地层速度在整个勘探开发的各个环节上都有着重要的意义。随着近些年勘探程度的加深,勘探区域向更深处及更复杂区域方向发展,地震资料采集条件更复杂,地下速度的横向变化更剧烈,地层速度越来越不容易精确获取。如何在纵、横向岩性、矿物变化快、非均质性强、构造幅度低的区域获取较为精确的地震速度场就成了一个至关重要的问题。恩平凹陷位于南海东部。区域内储层、盖层发育,紧邻油源,有良好的油气运移、保存条件。但特殊的地质构造条件和沉积环境导致该区域构造幅度低,同时纵、横向岩性变化快,钙质、灰质矿物分布不均匀,导致速度纵、横向变化都比较剧烈,同时该区域又处于勘探初期缺少钻井资料,本次的研究区域内存在三个断块,只有4 口探井,使得较为精确的求取速度场充满了挑战。本文通过使用叠前深度偏移、标定速度与VSP速度建立速度场、基于层状模型的常规变速成图和基于逐层数的分析的变速成图等多种方法,对区域构造进行深度转换及对比分析,提出了一种适用于该区域的速度分析构造研究方法。本文提出了一种速度场校正流程,首先利用VSP速度对叠前时间/深度偏移处理过程中获取的层析速度纵向趋势进行校正;再通过地质统计学反演结合测井规律预测出对速度影响较大的钙质、灰质成分的空间分布特征,结合岩石物理正演分析获取的井上各种矿物成分含量对速度影响的规律,对纵向趋势校正后的速度场进行补偿,最终获得纵、横向都符合地质规律的速度场。采用以上方法最终获取的速度场沿井旁道提取层速度曲线在纵向与测井得到的VSP层速度曲线相近,速度的横向变化也符合区域地质规律,有利于落实有利储层中幅度低的构造,较清晰的描绘圈闭边界,为之后的储量计算和经济前景评估打好基础。
[Abstract]:The study of velocity has always been a top priority in geophysics. The accuracy of the velocity field method has a direct impact on the accuracy of structural mapping and the implementation of traps. Accurate formation velocity is of great significance in all aspects of exploration and development. With the deepening of exploration in recent years, the exploration area develops further and more complex. Seismic data acquisition conditions are more complex, the lateral variation of underground velocity is more intense, the formation velocity is more and more difficult to obtain accurately. Obtaining a more accurate seismic velocity field in a region with low tectonic amplitude has become a crucial problem. Enping Sag is located in the eastern part of the South China Sea. The reservoir in the area is well developed, the cap is developed, the oil source is close to the oil source, and there is good oil and gas migration. Preservation conditions. But the special geological structural conditions and sedimentary environment lead to low tectonic amplitude, at the same time vertical, lateral lithologic changes, calcium, gray mineral distribution is uneven, resulting in the velocity longitudinal, lateral changes are more intense, At the same time, the area is in the early stage of exploration and lack of drilling data. There are three fault blocks and only four exploration wells in this study area, which makes the more accurate velocity field full of challenges. In this paper, prestack depth migration is used. The velocity field is established by calibrating velocity and VSP velocity, the conventional variable velocity mapping based on layered model and variable velocity mapping based on layer by layer number analysis are carried out, and the depth conversion and comparative analysis of regional structures are carried out. In this paper, a velocity field correction process is proposed. Firstly, VSP velocity is used to correct the longitudinal trend of tomography velocity acquired during prestack time / depth migration processing. Then the spatial distribution characteristics of calcareous and gray components, which have a great influence on velocity, are predicted by geostatistical inversion combined with logging law, and the law of the influence of mineral contents on velocity of wells obtained by rock physics forward analysis is analyzed. The velocity field corrected by the longitudinal trend is compensated, and finally the longitudinal velocity field is obtained. The velocity curve obtained by the above method is similar to the velocity curve of VSP layer obtained by logging, and the lateral variation of velocity conforms to the regional geological law. It is propitious to carry out the structure of favorable reservoir with low amplitude and clearly delineate the trapping boundary, which will lay a good foundation for the calculation of reserves and the evaluation of economic prospects.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13

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