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神经网络方法及储层动态模型的研究
Research on Dynamic Model of Reservoir with the Method of Neural Network
【作者】 刘建;
【导师】 徐守余;
【作者基本信息】 中国石油大学 , 地质工程, 2010, 硕士
【摘要】 长期注水开发过程中,地下储层参数在开发流体的作用下都发生了演变,建立能够反映储层参数在空间和时间上变化规律的储层动态模型,对于提高油气采收率、延长油田的寿命有着非常重要的意义。本文通过综合应用多学科的理论、方法和技术,并借助于计算机的手段,将数学和储层地质紧密结合,提出了一套新的建立储层四维模型的方法。主要取得了以下成果和认识:①分析了神经网络的算法原理和基本结构,并对常用于储层建模中的BP神经网络进行了研究,总结了传统的BP算法的推导。②针对BP算法在储层建模中困难和问题,提出了新的改进措施,即利用遗传算法来优化BP神经网络的权值和阈值,从而能够有效避免网络训练的局部最优化问题,节省网络的训练时间,使得所建模型能更好的的符合精度的要求。③充分利用计算机的手段,通过编程语言来实现遗传算法优化的BP算法,并利用新的算法来进行网络训练,建立起GA-BP神经网络的储层建模系统。④提出了一种新的建立储层四维模型的方法,即首先利用人工神经网络建立起储层参数的预测模型,得到储层参数的四维数据体,然后利用建模软件建立各个开发阶段的三维地质模型,从而实现了储层地质的四维建模。⑤以胜坨油田二区沙二段8砂层组3小层的三角洲前缘相储层为例,建立了储层宏观参数的四维模型,并对所建模型进行验证,能够得到较满意的效果。
【Abstract】 Reservoir parameters have been changed by the exploitation fluid. The reservoir dynamic model, which can reflect the reservoir parameter’s variation based on spatial and temporal, is set up. This has a significant meaning to lift the recovery ratio of oilfield and extend the life of oilfield.Mathematics and reservoir geology have been combined closely by applying synthetically multi-subject theories, methods and technology and making full use of computer. A new method to build the 4D reservoir model is proposed. Main achievements of the study are summarized as following: (1) Traditional BP derivation algorithm is put forward through the study of algorithm principle and basic structure of neural network and the BP neural network which commonly used in reservoir modeling. (2) New improvement measure (optimization weight and threshold of BP neural network based on genetic algorithm) is offered to overcome difficulties of BP algorithm applied in reservoir modeling. Then, the network can effectively avoid local optimization problem of network training and save network training time. The model built in this paper can meet the requirement of high accuracy. (3) Optimization BP algorithm based on genetic algorithm is offered by making full use of computer, especially programming language. And reservoir modeling system of GA-BP neural network is built by the optimization BP algorithm. (4) A new method to built 4D reservoir model is proposed in this paper. Firstly, build a prediction model of reservoir parameters to have its 4Ddata volume. Secondly, build 3D geological models of each development phases by means of modeling software to get the 4D reservoir model. (5) A 4D reservoir model of macro-parameter is built based on change rule of delta reservoir parameters were researched in Layer 83 of Es 2 in the second block of Shengtuo Oilfield exploited by water-flooding for a long time, and have a flavor result by verification.
【Key words】 3D geological model; 4D geological model; genetic algorithm; BP neural network;