Research And Application Of Deep Water Completion Method Based On Fuzzy Mathematics

At present, the theory and application of optimum completion method for onshore oil and gas field has been successful which provides some ideas for the deep water oil and gas field. Completion method optimization for onshore is mainly based on a variety of factors, such as geological characteristics, oil properties and engineering factor. Also, it used the productivity dynamic prediction model and economic evaluation to chooses the optimum completion method. But with the vigorous development of deepwater oil and gas fields in China, onshore oil and gas well completion method optimization model is not suitable for the deepwater oil and gas field. So, This paper focuses on the subject of deep water well completion method optimization based on fuzzy mathematics. Thesis carried out the research as following five parts.(1) The establishment of the principle of deep water well completion optimization. Researching the completion method commonly used in the deepwater oil and gas fields, and combining with the influence of traditional selection of completion methods factors and optimum principle, proposed a kind of completion method optimization principle deepwater oil and gas fields.(2) Determination of deep water well completion optimization evaluation index and data processing method. Based on the analysis of characteristics of deepwater completions, established four evaluation models:the productivity prediction, economic evaluation, project evaluation, HSE evaluation and the corresponding ten index evaluation system. In this paper, the evaluation indexes include the quantitative index and qualitative index. The quantitative index is mainly obtained through productivity prediction model and economic evaluation model. For qualitative indicators, due to the inability to calculate, often use fuzzy mathematics method to solve this problem. In order to change the fuzzy evaluation into a numerical data, we established the indicators quantized table. Then it used the set value statistics to get the objective data. In addition, according to the potential risks of every well completion method construction, it established completion operation risk of accident tree, which is used to evaluate the risks of different completion method. Finally it was transformed into mathematical probability.(3) Determine the optimal evaluation index weight value. AHP is very practical and effective in the treatment of complicated decision-making problems, and having a complete theory in determining the weight hierarchy model. It used AHP to calculate the weight of evaluation index system of deep water well completion optimization value for deepwater completions, which provides a theoretical support to the deep water well completion method optimization.(4) The establishment of deep water well completion method optimization model. According to the characteristics of deep water well completion, it used the information entropy method, the grey system method and the Vague method to choose the better completion method, which were the uncertainty of system. Finally it used the inferior order method, average method of three kinds of different method to get the optimization results by comprehensive ranking.(5) Application and verification of completion optimization model in the LIBONOLO deep water oil field. According to the successful application of optimization model, the optimization model was programmed by Visual Basic, which makes the process more simple and intuitive.