【作者】 鞠志忠；

【导师】 刘扬；

【作者基本信息】 大庆石油学院 ， 油气储运工程， 2010， 博士

【摘要】 随着大庆外围油田开发进入中、高含水期,地面原油集输系统普遍呈现出负荷率下降、运行效率降低、系统能耗升高等一系列不协调现象,导致原油生产成本增加。因此在集输系统落实节能降耗措施、深化研究优化、简化技术已成为油田地面总体规划中的重点工程。针对大庆外围低渗透油田所采用的集输工艺流程,以提高油田开发建设经济效益、降低地面建设投资和生产运行能耗为研究目标,开展了降温集输技术界限和管网优化设计方面的研究工作。主要研究成果如下:(1)研制能够充分模拟原油物性、土壤环境温度、集油管规格及流速等工况条件变化对掺水集输工艺参数影响的试验装置,可综合集输管路的温降、压降变化,油水流型及管壁沉积物分析结果确定冷输技术界限;(2)试验表明:增大回油系统含水、合理提高流速均有利于减少低温流动过程中的压力损失,确保低温集输工艺的实施;高含水期回油温度可降低到原油凝固点以下3～5℃;集输系统原油含水率及流速是影响油水流型的主要因素,且“水环油包水核(W/O&W)”的混合流型属于冷输管路两相流动的典型流型;(3)冷输管路的管壁沉积层是一个结构布满空隙,中间充满原油、胶质、沥青质、水分和其它机械杂质的混合物,管路内的沉积归于分子扩散、布朗运动、剪切弥散及重力沉降等四种机理;(4)大庆外围低渗透油田现场降温集输试验表明,在确定回油温度为32℃的情况下,综合热力与动力费用,以最经济运行为目的,建议夏季掺水温度为50～56℃,平均单井掺水量0.58 m3/h,冬季掺水温度为57～63℃,平均单井掺水量0.67m3/h。(5)针对低渗透油田普遍采用的星形和环形油气集输管网,以降低管网建设投资为目标,分别研究建立了管网布局——分配优化问题的数学模型,分析模型的结构特点和计算复杂性,给出了相应的混合遗传模拟退火算法求解策略。(6)分别研究建立布局区域内存在障碍的星形和环形油气集输管网布局-分配优化问题的二级混合规划数学模型及相应的求解方法。(7)以管网建设投资、动力能耗和热力能耗最小为目标研究建立了单管环状掺水集油管网多目标参数优化设计数学模型。根据油田实际开发情况及设计者意图,采用评价函数方法给出了多目标优化问题的替换模型,并采用混合遗传算法进行有效求解。更多还原

【Abstract】 With the development of Daqing peripheral oilfields entering the middle and high water-cut stages, the surface oil gathering and transportation system widely experienced a series of inconsistent situations, such as the drop in load rate, decline of operation efficiency and rise of energy consumption, which leads to the increase in production cost of crude oil. Therefore, the implementation of energy-saving and consumption-reducing measures, deep optimization research and technology simplification for the gathering and transportation system have fallen within the key projects in the overall surface plan of oilfield. For the gathering and transportation process adopted in the low-permeability peripheral oilfields of Daqing, we carried out such researches on the technical limits of cooling gathering & transportation and the design optimization of pipe network in order to enhance the economic benefit of oilfield development and construction and to reduce the investment in surface construction and energy consumption of productive operation. The main research results are given as bellow:(1) Develop the test device to fully simulate the influence of physical property of oil, temperature of soil environment, specification of oil-gathering pipe, flow rate and other working conditions on the parameters of water-mixing gathering and transportation process, and to determine the technical limits of cold transportation based on the comprehensive results of analysis on temperature drop of gathering & transportation pipes, change in pressure drop, oil-water flow pattern and deposit on pipe wall;(2) According to the test, the increase in water content of oil return system and reasonable improvement of flow rate can help to reduce the pressure loss during the low-temperature flow and ensure the implementation of low-temperature gathering & transportation process; the oil return temperature in the high water-cut stages can be reduced to 3~5℃bellow the solidification point of crude oil; the crude oil’s water-content rate and flow rate in the gathering and transportation system serve as the main factors to affect the oil-water flow pattern, and the mixing flow pattern of“water-in-oil-in water (W/O&W)”is the typical flow pattern of two phase flow in the cold transportation pipeline.(3) The deposits on the wall of cold transportation pipeline is a mixture featuring loose structure, with the holes fully filled with crude oil, gelatine, asphaltene, water and other mechanical admixture; the deposition in the pipeline follows such four mechanisms as molecular diffusion, Brownian movement, shear dispersion and gravity settlement.(4) The field cooling gathering & transportation test for the low-permeability peripheral oilfields of Daqing shows that in order to realize the most economical operation (namely lowest heat and power expenses) given the oil return temperature of 32℃, it is suggested that the water injection temperature in summer shall be 50~56℃, with average water injection amount of single well being 0.58 m3/h, the water injection temperature in winter shall be 57~63℃, with average water injection amount of single well being 0.67m3/h.(5) For the star-like and looped oil/gas gathering and transportation pipe networks widely adopted by the low-permeability oilfields, we study and establish a mathematical model for the location-allocation optimization of pipe network, analyze the structure features and computational complexity of model, and give the corresponding solution strategies of hybrid genetic-simulated annealing algorithm, with a purpose to reduce the investment in the construction of network.(6) Respectively study and establish the secondary hybrid planning mathematical model and the corresponding solving method for the location-allocation optimization of star-like and looped oil/gas gathering and transportation pipe network which has obstructions in the distribution area.(7) Study and establish a mathematical model for the multi-objective optimization design of single-pile looped oil gathering pipe network featuring water injection in order to minimize the investment in pipe network construction and the power and heat consumption. In accordance with the actual development situation of oilfields and the intents of designer, adopt the evaluation function method to give the alternative model of multi-objective optimization problem, and work it out through the hybrid genetic algorithm.更多还原