| This essay has studied optimization question of the offshore reservoirs exploited by horizontal wells. Firstly in macroscopic view, it has studied and selected the types of reservoirs which are suitable to horizontal wells and the range of the corresponding parameters. It has also discussed the acquisitive methods of the data of horizontal wells reservoir engineering as well as the types of the data needed to acquire. Then in microscopic view, it is based on the theory of mathematical models and develops to the analysis theory of horizontal wells systems. And on the basis of studies above, the optimization design method, transient well test and the nodes of horizontal wells analysis method have been studied. The research approaches have comprehensively adopted percolation mechanics, reservoir engineering, modern mathematics and modern calculation technology and so on. By studying, the achievements received are as follows:(1) It has discussed and studied the suitable types of exploitation reservoirs of horizontal wells and the range of corresponding parameters in detail so as to provide the material basis of the effective exploitation of horizontal wells.(2) It has studied the acquisitive methods of the data of horizontal wells reservoir engineering and the types of the data needed to acquire so as to provide the important information basis of effective exploitation of reservoir through horizontal wells, all of which will play an important role in reservoir exploitation and management.(3) It has comprehensively and attentively studied the analysis theory of horizontal wells' productivity in closed, constant pressure boundary, bottom water, gas cap and edge water reservoir, and it also analyze how productivity of horizontal wells is influenced by the length, position of horizontal wells and anisotropy of reservoir and so on so as to provide the theoretical basis for deciding optimization design, rational working system of horizontal wells and production engineering.(4) It has delved into the geological elements needed to consider during the optimization design of horizontal wells in detail. On the basis of criticalproduction of horizontal wells and water, gas breakthrough time, it has studied the optimistic position of horizontal wells in bottom water, gas cap and gas cap bottom water reservoir for the first time. And from the angle of technical economy, reservoir percolation and flow coupling in the well bore of horizontal wells , it has also studied the subject about optimistic length of horizontal wells sections for the first time. Moreover, it has finished the optimization calculations of the position and length of actual sample of horizontal wells .All these studies will be beneficial to extension of the water-free oil production period of horizontal wells and decrease of the exploitation costs.(5) In this essay, we have made a mathematical model of unstable percolation of horizontal wells in the border reservoir of unlimited, closed and constant pressure on the basis of the solution to the model ,we draw the typical curves of well test analysis, and analyze the dynamic elements which affect the unstable pressure of horizontal wells. We also systematically and comprehensively analyze the percolation characters. As a result, we have completely described the pressure drawdown and build-up conventional well test method of horizontal wells, and also provided chart match analysis of characteristic values and three kinds of modern well test analysis of characteristic values which belongs to a new idea of the studies of this essay, for there is still no reports from domestic documents. Meantime, we have explained the pressure build-up material of actual measurement horizontal wells by means of the match method of chart and analysis method of characteristic values, and acquired reliable results. The analysis and studies of horizontal wells test provide a kind of important means and methods to understand the dynamic characters of reservoir.(6 ) It has studied the selection method of the pro...
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