Research on a TOPSIS energy efficiency evaluation system for crude oil gathering and transportation systems based on a GA-BP neural network

As the main link of ground engineering,crude oil gathering and transportation systems require huge energy consumption and complex structures.It is necessary to establish an energy efficiency evaluation system for crude oil gathering and transportation systems and identify the energy efficiency gaps.In this paper,the energy efficiency evaluation system of the crude oil gathering and transportation system in an oilfield in western China is established.Combined with the big data analysis method,the GA-BP neural network is used to establish the energy efficiency index prediction model for crude oil gathering and transportation systems.The comprehensive energy consumption,gas consumption,power consumption,energy utilization rate,heat utilization rate,and power utilization rate of crude oil gathering and transportation systems are predicted.Considering the efficiency and unit consumption index of the crude oil gathering and transportation system,the energy efficiency evaluation system of the crude oil gathering and transportation system is established based on a game theory combined weighting method and TOPSIS evaluation method,and the subjective weight is determined by the triangular fuzzy analytic hierarchy process.The entropy weight method determines the objective weight,and the combined weight of game theory combines subjectivity with objectivity to comprehensively evaluate the comprehensive energy efficiency of crude oil gathering and transportation systems and their subsystems.Finally,the weak links in energy utilization are identified,and energy conservation and consumption reduction are improved.The above research provides technical support for the green,efficient and intelligent development of crude oil gathering and transportation systems.

Flow Characteristics of Crude Oil with High Water Fraction during Non-heating Gathering and Transportation

In order to ensure the safety of the non-heating gathering and transportation processes for high water fraction crude oil,the effect of temperature,water fraction,and flow rate on the flow characteristics of crude oil with high water fraction was studied in a flow experimental system of the X Oilfield.Four distinct flow patterns were identified by the photographic and local sampling techniques.Especially,three new flow patterns were found to occur below the pour point of crude oil,including EW/O&W stratified flow with gel deposition,EW/O&W intermittent flow with gel deposition,and water single-phase flow with gel deposition.Moreover,two characteristic temperatures,at which the change rate of pressure drop had changed obviously,were found during the change of pressure drop.The characteristic temperature of the first congestion of gel deposition in the pipeline was determined to be the safe temperature for the non-heating gathering and transportation of high water cut crude oil,while the pressure drop reached the peak at this temperature.An empirical formula for the safe temperature was established for oil-water flow with high water fraction/low fluid production rate.The results can serve as a guide for the safe operation of the non-heating gathering and transportation of crude oil in high water fraction oilfields.

Large Potential Exists in China's Oil & Gas Transportation System

As China in the decades ahead is to go through significant reorganization in the power sector and the petrochemical industry will see considerable growth,the transportation infrastructure for petroleum and gas should have a new shape. Implementing the largest infrastructure projects and creating on this basis a modern transportation network will not only see a new reincarnation of traditional industrial centers, but also open wider opportunities for regional development.

The challenges facing the oil and gas storage and transportation technology and its developing direction

In recent years, our country is increasingly dependent on the use of the oil resources, and the degree of the oil mining is also continuously upgrading. After the completion of the tasks related to the oil mining in the lands, the technologies for the development of the offshore oil mining are particularly important. Among these problems, after the exploitation, the storage and transportation of the offshore oil and gas is worthy of the discussion of the technical personnel. From the experience of the oil and gas storage and transportation in the long years, in some environmentally degraded areas, there are problems in the efficiency and safety in the long pipeline transportation and the oil and gas mixed transportation, and in the transportation, there are also big shortcomings. In this paper, the author carries on the analysis of the existing questions encountering in our country＇s oil and gas storage and transportation~ and proposes the direction of the researches in the future oil and gas storage and transportation, and the purpose is to better improve the security of Cbina＇s oil and gas storage and transportation and to enhance the efficiency of the use of the oil and gas.

The development status and the prospect of the pipeline robots in the oil and gas storage and transportation industry

In the process of the constant development of the oil and gas storage and transportation technology, the maintenance of the large pipelines is an important task. At present, China vigorously promotes the use of the pipeline robots, for the maintenance of the oil and gas pipelines by the unique characteristics of the robots. In this paper, the author carries out the detailed analysis on the current situation of the development of the pipeline robots in the oil and gas storage and transportation industry, and compares the different applications of the pipeline robots at home and abroad. Starting from the principles of the operation of the robots, the author analyzes the characteristics of the different types of the robots, and combined with the existing conditions of the oil and gas storage and transportation in our country, the author tries to find the most favorable way of the working of the pipeline robots, to continuously improve the development of the oil and gas storage and transportation industry using the robot technologies.

Current State and Prospects of CNPC's Oil and Gas Storage and Transportation

Oil and gas transportation facilities are important for a country to secure an energy supply and maintain social stability and economic development.Social capitals in China are now encouraged by the government to invest in the construction of oil and gas infrastructures in the country.With China's growing economy and new reforms in the oil and gas sector,more opportunities are available for private companies seeking to get involved in energy infrastructure.It is estimated that the future market of energy infrastructure projects in China is valued at nearly RMB 2 trillion.This paper is trying to offer some clues regarding investment in energy infrastructure in China by giving a brief introduction to the current situation of CNPC's oil and gas infrastructure construction.

Main Indexes of Pipeline Transportation of Crude Oil and Gas

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Reform Exploration for Safety Course System of Oil and Gas Storage and Transportation Facilities

In recent years,the safety of oil and gas storage and transportation facilities has been paid more attention by the state and enterprises due to frequent accidents.The oil and gas storage and transportation facilities safety courses in China University of Petroleum(Beijing)includes“Engineering mechanics”,“Strength design of pipelines and tanks”and“Safety and integrity management of oil and gas storage and transportation facilities”.The three courses lack relevance and the teaching mode is too rigid,resulting in students losing their initiative in learning.If students can’t use the knowledge flexibly,it will affect the achievement of the objectives of the training program.Therefore,oil and gas storage and transportation facilities safety courses are reformed,training plans are adjusted and teaching methods are improved.The practice shows that the reform enriches the teaching content,improves the teaching quality,stimulates classroom activity and gets a good evaluation of students.The reform of safety courses has a certain significance for cultivating compound talents who have the ability to solve practical problems in engineering.

A STAMP-Game model for accident analysis in oil and gas industry

Accidents in engineered systems are usually generated by complex socio-technical factors.It is beneficial to investigate the increasing complexity and coupling of these factors from the perspective of system safety.Based on system and control theories,System-Theoretic Accident Model and Processes(STAMP)is a widely recognized approach for accident analysis.In this paper,we propose a STAMP-Game model to analyze accidents in oil and gas storage and transportation systems.Stakeholders in accident analysis by STAMP can be regarded as players of a game.Game theory can,thus,be adopted in accident analysis to depict the competition and cooperation between stakeholders.Subsequently,we established a game model to study the strategies of both supervisory and supervised entities.The obtained results demonstrate that the proposed game model allows for identifying the effectiveness deficiency of the supervisory entity,and the safety and protection altitudes of the supervised entity.The STAMP-Game model can generate quantitative parameters for supporting the behavior and strategy selections of the supervisory and supervised entities.The quantitative data obtained can be used to guide the safety improvement,to reduce the costs of safety regulation violation and accident risk.

Proppant transport in rough fractures of unconventional oil and gas reservoirs

A method to generate fractures with rough surfaces was proposed according to the fractal interpolation theory.Considering the particle-particle,particle-wall and particle-fluid interactions,a proppant-fracturing fluid two-phase flow model based on computational fluid dynamics(CFD)-discrete element method(DEM)coupling was established.The simulation results were verified with relevant experimental data.It was proved that the model can match transport and accumulation of proppants in rough fractures well.Several cases of numerical simulations were carried out.Compared with proppant transport in smooth flat fractures,bulge on the rough fracture wall affects transport and settlement of proppants significantly in proppant transportation in rough fractures.The higher the roughness of fracture,the faster the settlement of proppant particles near the fracture inlet,the shorter the horizontal transport distance,and the more likely to accumulate near the fracture inlet to form a sand plugging in a short time.Fracture wall roughness could control the migration path of fracturing fluid to a certain degree and change the path of proppant filling in the fracture.On the one hand,the rough wall bulge raises the proppant transport path and the proppants flow out of the fracture,reducing the proppant sweep area.On the other hand,the sand-carrying fluid is prone to change flow direction near the contact point of bulge,thus expanding the proppant sweep area.

Natural Gas Gathering and Purification in Sichuan Gas Fields

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超临界水环境下稠油改质降黏特性实验

通过室内实验和测试分析,系统阐述超临界水环境下稠油改质降黏的宏观及微观特征,并分析反应温度、反应时间、油水比3种反应参数对产物及降黏效果的影响。研究表明:经超临界水处理后,稠油流动状态显著改善,平均降黏率达99.4%。反应温度过高,将导致胶质和沥青质含量增加,焦炭产量显著提升,最佳温度为380~420℃;反应时间过长,稀油产量持续增加,但胶质与沥青质含量也有所提升,最佳反应时间约为150 min;减小油水比有助于改善反应体系内的扩散环境,降低胶质与沥青质含量,但稠油处理成本增加,油水比为1∶2时可兼顾改质降黏效果与经济性。3种反应参数与油样黏度的相关性由高到低排序为温度、时间、油水比;稠油四组分含量中,黏度受沥青质含量影响最大,芳香烃次之,受胶质和饱和烃含量影响较小。

光热稠油沉降罐的应用前景

油田开发进入中高含水阶段,稠油采出液含水率上升,对传统油水分离和加热技术提出挑战。本文综述了光热稠油沉降罐的应用前景,探讨了其基本原理及其在油水分离中的作用。同时,分析了光热集热系统的发展现状及其在稠油沉降罐中的应用。该技术融合太阳能与燃气加热,提升油水分离效率,实现加热后污水的循环利用,减少能源消耗和环境污染。研究表明,光热稠油沉降罐技术在提升生产效率、降低成本及环境保护方面具有明显优势,对油田可持续发展具有积极影响。

油田低温集输技术可行性研究及应用

随着大庆油田逐渐进入开采后期,采出液平均含水率高达95%以上,现有的掺水集油工艺会造成地面集输系统的大量热能损失。为实现油气集输系统节能降耗,采用低温集输技术,参照临界粘壁温度经验算法并通过摸索试验,得出水聚驱不同产液量、含水率的集油环生产情况临界粘壁温度,按照“一井一策、一间一掺水”的创新管理模式,将粘壁温度作为集输界限指导低温集输工作,共试验水驱174口、聚驱10口采出井,累计减少掺水量29.6×10^(4) m^(3),年节气量103.6×10^(4) m^(3),实现油田节能降耗。

含气油井采出液低温集输工艺界限研究

老油田因开发时间较长,存在产液量低、含水率高、能耗大等问题。为降低老油田高含水区块的运行能耗,针对低含气油井和高含气油井开展了降温实验,根据井口回压和进站温度随时间的变化规律,获取了含气油井采出液的低温集输工艺界限。结果显示:低含气油井在降温过程中出现了两个压力突变点,高含气油井在降温过程中压力呈不规则变化,但也出现压力突变区域;产液量越大、含水率越高、气液比越大,越有利于油井进行低温集输。推广区块内有55口油井从双管掺水工艺转为低温集输工艺,实施后全年可节约运行费用235.9万元,减少CO_(2)排放量为2650 t,节能减排效果明显。

低含水阶段含蜡原油不加热集油温度下限确定

油田开发初期,井口采出液含水率较低,管流在集输过程中极易形成W/O乳状液,当集油温度降低时,蜡分子析出,凝油大量黏附积聚在管道内壁,导致井口回压升高,严重时可能会发生堵管等事故,对降温输送产生了巨大阻碍。因此针对低含水阶段含蜡原油开展不加热集油温度下限研究,本文提出不加热集输温度边界条件判定方法,对于开发初期油田不加热集输工艺的开展具有重要意义。利用室内可承压模拟罐装置进行了低含水含蜡原油粘壁实验,对低含水阶段含蜡原油的粘壁规律进行了分析,确定了凝点、含水率、剪切速率是影响粘壁温度的主要因素,建立了低含水阶段含蜡原油不加热集输粘壁温度预测模型,利用油田现场环道实验装置进行了验证,误差在2℃范围内,满足工程运用需求。

杏北油田掺水系统全流程能量优化方法的研究与应用

油田含水率的上升和产液规模的不断增大,导致集输能耗逐年增加,如何保持开发效益,降低集输能耗,成为高含水开发阶段面临的一大难题。随着节能工作不断深入,潜力已得到很大程度的挖掘,常规技术节能空间小,能耗管控压力大。因此开展能量系统优化技术研究,该方法转变原来区域优化的方式,统筹采油井、计量间、转油站、脱水站四个环节,通过确定末端能耗需求,逐级推导前端各环节能供给的方式,指导集输系统精细化、低能耗生产运行。杏北油田自2017年应用能量优化运行技术,由点及面逐步扩大规模,已实现水驱转油站全覆盖,截至目前累计节气5 621×10^(4)m^(3),节电3 275×10^(4)kWh,为油田集输系统降本增效提供了指导依据。

小样本预测埋地管道外腐蚀速率

为解决现有线性回归模型、单一支持向量机和遗传算法优化支持向量机(GA-SVM)等管道腐蚀速率预测准确率低的难题,选取总含盐量、氧化还原电位、pH值、氯离子浓度、硝酸根浓度、硫酸根浓度、溶解氧含量、自然腐蚀电位等埋地管道外腐蚀速率的主要影响因素作为输入变量,采用麻雀搜索算法优化支持向量机算法,建立了麻雀搜索优化的支持向量机(SSA-SVM)腐蚀速率预测模型。测试集验证结果表明,SSA-SVM模型的决定系数R2为0.9919,高于线性回归模型(0.7189)、单一支持向量机(0.8442)和GA-SVM(0.9137);均方根误差为0.0686 mm/a,低于其他3种模型的0.1166、1.7745、0.1183 mm/a;平均绝对误差为0.0902 mm/a,低于其他3种模型的0.1474、1.7056、0.0977 mm/a;平均相对误差为3.94%,低于其他3种模型的25.59%、32.29%和6.42%。采用此模型随机选择B管道8组检测数据预测埋地管线外腐蚀速率,与现场实际年腐蚀速率对比预测精度为0.9642,高于GA-SVM的预测精度0.6690,表明该模型可应用于埋地管道的外腐蚀量和腐蚀速率预测,为埋地管道的安全运行提供数据支持。

原油集输系统能耗影响因素的综合判定模型

随着油田生产能源需求的不断增长,原油集输系统在能源供应链中所起的作用日渐显著,其能耗所占比重在整体油田生产中也日益增加,而系统能耗又受到多种因素的制约,如何科学合理地分析集输系统能耗影响因素成为油田面临的重要课题。同时,部分因素之间还会存在交叉影响而造成信息重叠,这给准确把握系统能耗主要影响因素带来较大难度。结合集输系统能耗构成特点和生产实际运行状况,综合考虑产液量、含水率、油品黏度等影响集输系统能耗的客观因素,采用改进熵权法、主成分分析法以及多元逐步回归分析法对各项因素的影响程度进行定量描述,根据权重大小进行排序,并将3种方法结合进行综合判定,确定含水率和产液量为影响油田集输系统能耗的主要影响因素,最后针对主要因素变量对系统的相关制约原因进一步深入探究,并提出系统具体降耗措施,以期为原油集输系统节能提效提供理论参考。