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.

Gathering and Transportation Technology of Heavy Oil in Liaohe Oilfield

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Transport and behavior of marine oil spill containing polycyclic aromatic hydrocarbons in mesocosm experiments

Polycyclic aromatic hydrocarbons(PAHs)are one of the most important groups in oil,and re sponsible for major toxic and/or carcinogenic impact on humans and wildlife.It is important to understand the behavior of PAHs in marine environment after an oil-spill incident.However,interaction between petroleum PAHs and microbial communities in a marine environment remains unclear.Therefore,a series of mesocosm experiments were conducted.in which water-accommodated fraction(WAF)of oil was generated to simulate an oil-spill scenario and to analyze the transport and behavior of marine oil spill containing PAHs with and without dispersants.Results indicate that the application of dispersant could increase the concentration of total PAHs in water column due mainly to significant increase in the concentration of highmolecular weight(HMW)PAHs at a lower removal rate.At the end of the 7-day experiment,significant amount of HMW PAHs were accumulated in sediment.In general,the application of dispersant did not increase the sediment uptake of PAHs but increased the PAHs concentration in water column.

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.

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.

Emulsification of Indian heavy crude oil using a novel surfactant for pipeline transportation

The most economical way to overcome flow assurance problems associated with transportation of heavy crude oil through offshore pipelines is by emulsifying it with water in the presence of a suitable surfactant.In this research,a novel surfactant,tri-triethanolamine monosunflower ester,was synthesized in the laboratory by extracting fatty acids present in sunflower（Helianthus annuus）oil.Synthesized surfactant was used to prepare oil-in-water emulsions of a heavy crude oil from the western oil field of India.After emulsification,a dramatic decrease in pour point as well as viscosity was observed.All the prepared emulsions were found to be flowing even at 1°C.The emulsion developed with 60%oil content and 2wt%surfactant showed a decrease in viscosity of 96%.The stability of the emulsion was investigated at different temperatures,and it was found to be highly stable.The effectiveness of surfactant in emulsifying the heavy oil in water was investigated by measuring the equilibrium interfacial tension（IFT）between the crude oil（diluted）and the aqueous phase along with zeta potential of emulsions.2wt%surfactant decreased IFT by almost nine times that of no surfactant.These results suggested that the synthesized surfactant may be used to prepare a stable oil-in-water emulsion for its transportation through offshore pipelines efficiently.

Characteristics of Oil Contamination and Numerical Modelling of Its Transport in Fracture-Karst Water in Zibo City,China

In this paper, the hydraulic characteristics of the fracture-karst aquifer and the distribution patterns of petrochemical contaminants are studied. Then, a numerical model using the mixed Eulerian-Lagrangian approach is constructed to predict the distribution and transport of petrochemical compounds in groundwater. The results of numerical modelling and sensitivity analysis show that it may be a workable way for aquifer remediation to combine contamination sources control and capture zone establishment.

Effect of TiO2 Nanoparticles on Charge Transportation in Mineral Oil and Natural Ester Based Nanofluid

TiO2 semiconductive nanoparticles are added into mineral and ester based transformer oil to form semiconductive nanofluids (SNFs) with the aim of enhancing the oil’s insulating performance. Charge accumulation and decay characteristics of both pure oils and SNFs are measured by pulse electroacoustic (PEA) technique. The result reveals that compared with pure oil, SNFs have more uniform in- ternal electric fields with voltage applied and higher charge decay rate after removing the applied voltage. This is caused by the increase of shallow trap density in SNFs, due to the test results of thermally stimulated current (TSC). It is proposed that the electron trapping and de-trapping processes in shallow traps could be the main charge transport processes in the nanofluid transformer oil.

Experimental Study and Simulation Principles of An Oil-Gas Multiphase Transportation System

Presented is an experimental study on the performance of an oil-gas multiphase transportation system, especially on the multiphase flow patterns, multiphase pumping and multiphase metering of the system. A dynamic simulation analysis is conducted to deduce simulation parameters of the system and similarity criteria under simplified conditions are obtained. The reliability and feasibility of two-phase flow experiment with oil and natural gas simulated by water and air are discussed by using the similarity criteria.

Natural Gas Gathering and Purification in Sichuan Gas Fields

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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.

GA与分层优化结合的掺水集油工艺参数优化

为降低进入特高含水阶段油田的掺水集油能耗,对掺水集油工艺参数进行优化。以掺水温度、掺水量、掺水压力为外层决策变量,加热炉和掺水泵运行方案为内层决策变量,以掺水集油工艺综合能耗最低为目标函数,建立掺水集油工艺参数优化模型。提出了一种遗传算法(Genetic Algorithm,GA)与分层优化结合的求解策略,将掺水温度作为染色体上的基因,先优化个体对应加热炉和掺水泵运行方案,得到个体对应的最小集油能耗,再通过种群的不断迭代进化,得到掺水集油工艺的最优参数。研究结果表明,与优化前相比,掺水温度降低8.3℃,掺水量减少131.6 m^(3)/d,掺水压力降低0.15 MPa,集输吨液综合能耗降低13.64%,优化效果良好。研究成果可为进入特高含水阶段油田降低掺水集油能耗提供借鉴。

大庆油田能效评价指标体系及能效综合评价方法研究

针对现行油田主要生产系统能效评价指标及其限值和评价方法对于大庆油田不完全适用的问题,根据工作内容,将油田生产系统划分为机采、集输、注水3个子系统;根据用能的关联性,将油田生产系统划分为机采集输和注水两个子系统,对于这两种子系统的划分,分别建立了能效评价指标体系。体系中的能效评价指标均分为系统级、单元级和设备级3个层级;明确了体系中各项指标的定义、计算方法、基础参数来源及统计口径。基于大庆油田实际情况,根据开采区块类型、驱替方式等,将测试数据进行分组,用统计方法确定每组各个能效指标的优良和合格限值;建立了单项与多项组合的油田生产系统加权能效综合评价方法,该方法综合考虑系统效率或系统单耗及其影响因素,在以较大权重计入系统级指标的同时,以较小的权重计入主要影响因素,即在要求系统指标的同时,也对单元级和设备级指标提出要求,从而分析评定所评价系统能效的提升空间。应用此评价方法对6个机采系统、1个集输和1个机采集输系统进行了能效综合评价。