The Cost Control Research Of Gas Field A’s Horizontal Wells

Horizontal well is defined as a well whose drilled hole angle greater than86°, which point of drilling directional drilling technology for a certain length of interval should be maintained, using the special downhole power tools and the MWD instrument. Contrast with vertical wells, horizontal wells have many distinct advantages. For example, horizontal wells can increase the contact area of the wellbore, and have high reserves. So horizontal wells are widely used in low permeability sandstone reservoir, thin layer of sandstone reservoirs, and multi-layer reservoir.Due to the distinct advantages, horizontal wells were into practice in gas field DND gradually, which achieved good results. At the international level, in some countries such as the United States, the cost of the horizontal wells is equivalent to the cost of vertical wells. But in gas field DND the cost of the horizontal wells is as3-4times as that of vertical wells. Horizontal wells’ large-scale applications made the production capacity of gas field promote greatly. However, such high cost restricts the gas field effective to further enhance. It is a problem gas fields facing that how to identify the key nodes from the horizontal well development process, and control the cost.In this paper, horizontal wells of gas field DND in a large oil and gas company were researched, whose aspects were analysed deeply. Horizontal wells’cost structure were interpreted using Monte Carlo method. Based on the research results of domestic and abroad scholars, four important factors were raised using the Minitab software. Finally, the measures of cost control were proposed.Based on the above ideas, this article includes six chapters:Chapter I is an introduction. Describes the background and research topics of significance, and overview of theories and methods of cost control and Monte Carlo method. Then propose the problems and the main content of this study. In oil and gas companies, the research of horizontal wells’ cost has important theoretical significance and practical significance. Rarely analyzing the cost of horizontal wells with Monte Carlo method be put into practice. On the basis of existing research, this paper analyze cost with the idea of Monte Carlo method integrated.Chapter II is related to the definition and theoretical basis. Introduces the idea of the Monte Carlo method, the basic theory of horizontal wells cost, the cost of the project analysis method, and the theoretical basis of the principle of normal distribution, the Pareto principle, the theory of sustainable development, cost meticulous management theory. Monte Carlo method, based on the law of large numbers and the central limit theorem in probability theory, is designed to handle the uncertainty of a simulation technology. With the large uncertainty of various parameters in oil and gas development process, Monte Carlo method is used. The differences of technology between horizontal wells and vertical wells make the method of cost control different, which means horizontal wells cost control has its own peculiarities.Chapter III analyze cost structure in gas field DND with Monte Carlo method. Introduces the development status of horizontal wells in gas field DND. Analyzes the overall cost, development cost based on the basis of the analysis of horizontal well drilling process. Using Monte Carlo method analyze cost structure, and reach the idea that the second inclined section, the horizontal section and fracture are the focus of cost control process. After analyzing these process, we extract the controlled key factors, namely horizon, hole size, horizontal segment length, number of fracturing paragraph.Chapter IV analyzes the key factors of horizontal well in gas field DND based on Monte Carlo method. With Monte Carlo method, this paper analyzes the relation between layers and cost, the relation between layers and completion cycle, the relation between borehole size and cost, mainly from layers of horizontal wells, borehole size, the length of horizontal section, the number of fracturing segments. Without considering other factors, the best layer, the best borehole size.the best length of horizontal section, the best number of fracturing segments in the case of single-factor analysis.Chapter V recommends some cost control measures for gas field DND. The cost control measures of horizontal wells are proposed from three approaches:emphasis on full cost fine management, emphasis on exploration work to optimize the development plan, the strengthening of investment management, direction of the development to cluster wells and other unconventional horizontal wells.Chapter VI are conclusions of this study and research prospects.In this paper, some of these issues are personal opinions and proposed solutions by this study. In the large-scale application of horizontal wells for the occasion, on the basis of a certain theories, discussing the nodes that can be controlled provides a method of reference for China’s oil and gas companies and for future researchers.The innovation of this paper are as follows:I. At present, the technology of foreign horizontal wells is relatively mature. Domestic technology of foreign horizontal wells is relatively backward, and few scholars analyze costs and cost structure on the basis of technological process. In this paper, based on the analysis of horizontal wells process, we compared the cost between crafts, and give the important process, namely the second inclined section, the horizontal section and fracture.Ⅱ. Monte Carlo method is designed to handle the uncertainty problem. It can simulate complex systems on the basis of existing data. Since the various parameters of the horizontal wells is uncertain, we apply Monte Carlo method. Based on simulation of large-scale horizontal wells, we analyze the layer, hole size, horizontal section, staged fracturing’ effect on the input and output, which provides a theoretical reference for the horizontal wells’ cost analysis of China’s gas fields.