Current Situation and Prevention of Soil Erosion from Construction of West-East Natural Gas Transmission (Ningxia-Shaanxi Section)

In the research, problems and damages of soil erosions in West -East Natural Gas Transmission were analyzed; the reasons were summarized and the characteristics of soil erosion were researched in order to explore principles of pipeline prevention and seek countermeasures.

Natural Gas Types,Distribution Controlling Factors,and Future Exploration in the Western Qaidam Basin

The Paleogene and Neogene oil and gas in the western Qaidam basin have a regular distribution in three concentric zones from the edge to the center of the basin. Natural gas mainly occurs in the inner zone, and the gas-oil ratio of the northern area of the basin is significantly higher than that of the southern area. Large amounts of carbon isotope data of natural gas, plotted in X- shaped and comprehensive identification diagrams for the southern area and northern area, respectively, were used to identify the types of natural gas. The large-scale distribution of natural gas is highly consistent with the Ro values of major source rocks, but is poorly correlated with the type of organic matter. This indicates that the main controlling factor of natural gas distribution is organic matter maturity, and the kerogen types act as the basis for the formation of different types of natural gas. Paleouplifts and squeezed anticlines near hydrocarbon generation depression centers, which are major natural gas-rich regions, control the migration directions of natural gas, while hydrocarbon migration pathways and fault systems connecting gas sources are the most important factors for natural gas reservoir formation in the inner basin. Therefore, favorable zones for natural gas distribution can be predicted on the basis of the distribution of thermal evolution and the gas generation intensity of major source rocks as well as the structural map. The Shizigou-Youshashan- Yingdong-Dawusi, Youquanzi -Kaitemilike - Youdunzi, and Xiaoliangshan - Nanyishan - Dafengshan structural belts are favorable zones for natural gas accumulation. This study has important theoretical and practical significance for future natural gas exploration.

Distribution and Chain Pattern of Liquefied Natural Gas Industry in China

The production and consumption of natural gas in China has been developing rapidly in recent years.It is expected that the annual growth rate of the demand for natural gas will reach 12% in the next 15 years,and the gas consumption in the primary energy will increase from 0.3% to 10% or more by 2020.However,since the supply of natural gas cannot satisfy the requirements,China has begun to build liquefied natural gas(LNG)terminals in the coastal regions such as Guangdong and Fujian,and solve this problem by importing LNG from foreign countries.LNG needs to be transported by LNG ships from abroad.With the rapid growth of global gas production,the volume of LNG trade also increases,and the interregional production increased from 0.3% in 1970 to 26.2% in 2004.So,we need LNG ships more than before.This article puts forward the distribution of LNG ships and the speculation of the future of LNG transportation based on the studies on foreign LNG production,the LNG trade,the building of LNG ships,the LNG transportation,the chain model of LNG distribution,etc.

The calculation and optimal allocation of transmission capacity in natural gas networks with MINLP models

The transmission capacity of gas pipeline networks should be calculated and allocated to deal with the capacity booking with shippers. Technical capacities, which depend on the gas flow distribution at routes or interchange points, are calculated with a multiobjective optimization model and form a Pareto solution set in the entry/exit or point-to-point regime. Then, the commercial capacities, which can be directly applied in capacity booking, are calculated with single-objective optimization models that are transformed from the above multiobjective model based on three allocation rules and the demand of shippers.Next, peak-shaving capacities, which are daily oversupply or overdelivery amounts at inlets or deliveries,are calculated with two-stage transient optimization models. Considering the hydraulic process of a pipeline network and operating schemes of compressor stations, all the above models are mixed-integer nonlinear programming problems. Finally, a case study is made to demonstrate the ability of the models.

Simulation of natural gas transmission pipeline network system performance

Simulation has proven to be an effective tool for analyzing pipeline network systems （PNS） in order to determine the design and operational variables which are essential for evaluating the performance of the system. This paper discusses the use of simulation for performance analysis of transmission PNS. A simulation model was developed for determining flow and pressure variables for different configuration of PNS. The mathematical formulation for the simulation model was derived based on the principles of energy conservation, mass balance, and compressor characteristics. For the determination of the pressure and flow variables, solution procedure was developed based on iterative Newton Raphson scheme and implemented using visual C＋＋6. Evaluations of the simulation model with the existing pipeline network system showed that the model enabled to determine the operational variables with less than ten iterations. The performances of the compressor working in the pipeline network system xvhich includes energy consumption, compression ratio and discharge pressure were evaluated to meet pressure requirements ranging from 4000-5000 kPa at various speed. Results of the analyses from the simulation indicated that the model could be used for performance analysis to assist decisions regarding the design and optimal operations of transmission PNS.

Distribution Characteristics and Accumulation Model for the Coal-formed Gas Generated from Permo-Carboniferous Coal Measures in Bohai Bay Basin, China: A Review

Coal-formed gas generated from the Permo-Carboniferous coal measures has become one of the most important targets for deep hydrocarbon exploration in the Bohai Bay Basin,offshore eastern China.However,the proven gas reserves from this source rock remain low to date,and the distribution characteristics and accumulation model for the coal-formed gas are not clear.Here we review the coal-formed gas deposits formed from the Permo-Carboniferous coal measures in the Bohai Bay Basin.The accumulations are scattered,and dominated by middle-small sized gas fields,of which the proven reserves ranging from 0.002 to 149.4×108 m3 with an average of 44.30×108 m3 and a mid-point of 8.16×108 m3.The commercially valuable gas fields are mainly found in the central and southern parts of the basin.Vertically,the coal-formed gas is accumulated at multiple stratigraphic levels from Paleogene to Archaeozoic,among which the Paleogene and PermoCarboniferous are the main reservoir strata.According to the transporting pathway,filling mechanism and the relationship between source rocks and reservoir,the coal-formed gas accumulation model can be defined into three types:"Upward migrated,fault transported gas"accumulation model,"Laterally migrated,sandbody transported gas"accumulation model,and"Downward migrated,sub-source,fracture transported gas"accumulation model.Source rock distribution,thermal evolution and hydrocarbon generation capacity are the fundamental controlling factors for the macro distribution and enrichment of the coal-formed gas.The fault activity and the configuration of fault and caprock control the vertical enrichment pattern.

A Novel Technology for Generation of Electricity and Cold by Using Energy Potential of Transmission Line＇s High Pressure Gas

The main objective of this paper is to develop a novel technology for combined generation of electricity and cold by using energy potential of transmission line＇s high pressure gas. For this purpose, the reduction of high pressure of the gas in gas distribution station instead of useless expansion throttling process is suggested to realize by adiabatic expansion, which is executed in a gas expanding turbine. Herewith, the gas distribution station is turned into energy and cold generating plant. Simultaneous operation of energy and cold generating plant is described. A method and appropriate formulas for determination of design characteristics of considered plant are suggested. A new method for reveres order of calculation and design of the cold store based on the use of expanded cold gas as cooling agent is developed. Calculations and analysis prove high energy efficiency of suggested technology, the wide use of which will provide significant production of cheap electricity and cold and as well as reduction of fossil fuel consumption.

Reliability analysis of urban gas transmission and distribution system based on FMEA and correlation operator

In order to improve the safety management of urban gas transmission and distribution system, failure mode and effects analysis （FMEA） was used to construct the reliability analysis system of the pipeline network. To solve the problem of subjectivity and uncertainty of the multi-expert decision making, the correlation operator was introduced into the calculation of the risk priority number （RPN）. Using FMEA along with weight analysis and expert investigation approach, the FMEA evaluation table was given, including five failure modes, risk priority numbers, failure causes and effects, as well as corrective actions. The results show that correlation operator can directly process the linguistic terms and quantify the priority of the risks.

Cascading Failure Propagation Simulation in Integrated Electricity and Natural Gas Systems

The sharp increase in the total installed capacity of natural gas generators has intensified the dynamic interaction between the electricity and natural gas systems,which could induce cascading failure propagation across the two systems that deserves intensive research.Considering the distinct time response behaviors of the two systems,this paper discusses an integrated simulation approach to simulate the cascading failure propagation process of integrated electricity and natural gas systems(IEGSs).On one hand,considering instantaneous re-distribution of power flows after the occurrence of disturbance or failure,the steady-state AC power flow model is employed.On the other hand,gas transmission dynamics are represented by dynamic model to capture the details of its transition process.The interactions between the two systems,intensified by energy coupling components(such as gas-fired generator and electricity-driven gas compressor)as well as the switching among the operation modes of compressors during the cascading failure propagation process,are studied.An IEGS composed of the IEEE 30-bus electricity system and a 14-node 15-pipeline gas system is established to illustrate the effectiveness of the proposed simulation approach,in which two energy sub-systems are coupled by compressor and gas-fired generator.Numerical results clearly demonstrate that heterogeneous interactions between electricity and gas systems would trigger the cascading failure propagation between the two coupling systems.

Development and application of Baosteel X80 large diameter UOE longitudinal submerged arc welded pipes

With the increase in energy demand, the demand for oil and gas transmission pipes, particularly high-grade longitudinal submerged arc welded pipes （LSAWs）, have been growing in recent years. The construction of the 2nd West -East natural gas transmission pipeline project shows that the oil and gas pipeline construction has entered a new phase of development with X80 pipes being applied in large scales for the first time in China. This paper briefly introduces the 2nd West-East natural gas transmission pipeline project and its main technical requirements with the focus on the features of API standard 5L X80 grade Ф 1219 mm series of U-ing-O-ing-Expanding （ UOE ） LSAW pipes, which Baosteel developed with the integrated technology for the 2nd West-East natural gas transmission pipeline project. The analysis shows the extra-low carbon content, the high contents of manganese and niobium, the fine microstructure, the high strength,the toughness and the good weldability of X80 pipes meet the requirements of ＂the technical specification of LSAW linepipes for the 2nd West-East natural gas transmission pipeline project in China＂. By the end of June 2010, Baosteel had totally produced 322000 t of Ф 1219 mm X80 UOE steel pipes, which have been successfully used in the 2nd West-East natural gas transmission pipeline project, thus filling the gap of the production of large diameter X80 UOE LSAW pipes in China.

Geochemical characteristics, genetic types, and controlling factors of natural gas in Jiyang Depression, Bohai Bay Basin (eastern China)

The Jiyang Depression is an important oil and gas production zone in the Bohai Bay Basin.Through a systematic investigation of the gas components and stable carbon isotopes,the genetic types of natural gas found in the Jiyang Depression were determined,that is,biogas,oilassociated gas,coal-derived gas,high-mature oil-related gas,and mantle-derived carbon dioxide(CO_(2)).From the results,natural gas in the Jiyang Depression can be divided into four groups.Group I,which is distributed in the northwest area,is the only typical oil-associated gas.Group II,distributed in the northeast area,is dominated by oil-associated gas,and involves biogas,coal-derived gas,and high-mature oil-related gas.Group Ⅲ,distributed in the southeast area,has all genetic types of gas that are dominated by oil-associated gas and have mantle-derived CO_(2).Group IV,distributed in the southwest area,is dominated by biogas and involves coal-derived gas and oil-associated gas.The differences in each group illustrate the lateral distribution of the natural gas types is characterized by the eastern and southern areas being more complex than the western and northern areas,the vertical distribution of gas reservoirs has no obvious evolutionary law.The main controlling factor analysis of the spatiotemporal changes of the gas reservoirs revealed that the synergy of geochemical characteristics,thermal evolution of the Shahejie Formation and Carboniferous-Permian source rocks,and sealing properties of various faults are jointly responsible for determining the gas reservoir spatiotemporal changes.

我国城市输配气运营投资机会研究

按照国家天然气发展规划,在产业政策方面,计划在2005年将天然气发展到140个城市,2010年增加到270个城市,21世纪中叶全国65%的城市将通上天然气。同时,城市燃气市场进入方式已有了根本改变,即实行特许经营制,这将会加快民营资本与外资的进入步伐;需求方面,由于天然气已逐渐成为民用能源市场上较便宜的品种,长输管道已连接了气源与东部能源消费旺盛的城市,且由于城市化进程的不断加快、城市居民收入水平的提高和生活方式的改变等都会促进天然气的消费。巨大的城市供气管网建设投资是城市燃气发展的瓶颈,但目前较高的接驳费收入以及相应的政府扶持政策基本上缓解了这一矛盾。在国家大力推进城市能源向天然气过渡的过程中,只要城市输配气运营企业能处理好可能发生的一些风险因素,就能获得可观的收益。

特高压线路固有频率特征分析及其在继电保护中的应用

利用分布参数等值特高压输电线路,分析不同故障类型情况下暂态高频分量的特征,提出一种基于暂态高频分量频域特征的故障类型识别和保护方案,讨论了实际应用中的关键问题及解决方法。通过多信号分类(multiple signal classification,MUSIC)算法分析故障后三相电流的频谱,计算线路一侧的电流频谱相关性和电流频谱能量,利用其进行故障识别和确定故障相,在此基础上,利用线路两侧故障相的电流频谱相关度判断区内、外故障。利用PSCAD对特高压线路模型进行了仿真验证,仿真结果证明了保护判据的有效性。

论天然气输配领域的自然垄断与监管

目前,我国天然气产业正处于快速发展时期。而天然气产业链中的天然气输配领域具有较强的自然垄断性,这既可产生规模经济,同时也存在着一定的弊端。因此,政府必须进行有效监管,以保护消费者利益,促进该行业持续健康发展。本文从自然垄断理论出发,借鉴国外天然气监管经验,阐述了我国政府在天然气输配领域进行监管的主要内容,包括:建立天然气管网公开准入机制,规制天然气管输价格,对输配领域实行特许经营权等,同时提出了与有效监管相关的配套对策建议。

论输配电网的自然垄断属性

输配电网的自然垄断属性是输配电管理体制改革的理论基础。本文从输配电网的技术经济特征入手,结合已有文献,对输配电网的自然垄断属性进行了深入研究。输配电网的自然垄断属性主要表现为规模经济和范围经济;规模经济和范围经济存在于输配电网的多个方面。理论和实证两方面的论据都支持或者不能否认输配电网的自然垄断属性。中国亟待进行相关研究,以便为电力体制改革提供理论指导。

提高北京天然气现有管网输气能力方法探讨

由于城市建设的快速发展,大中型城市普遍存在着"有限的土地资源与大量的天然气基础设施建设"相矛盾的现象,随着天然气需求量的增加,这一矛盾更为突出。如何利用现有管网设施提高管网输送能力,是目前亟待解决的问题。本文结合北京市天然气管网运行现状和未来天然气发展规划,系统分析了提高管网输气能力的方法。提出了提高管网输送能力的几种方法,如升压运行,中低压转换,扩大管径,源点增设,并行干管增设,连通线增设,成环改造等。最后,用统计理论的方法得到管线长度和天然气销售量回归方程,并分析了北京天然气管网利用率。本文研究结果,可为城市燃气管网改造提供科学的依据。

制约川渝天然气管道安全运行的问题与对策

管道安全关系到周边地区的公共安全、企业利益以及社会稳定,保障管道安全平稳输供气是天然气企业的重要责任。文章介绍了川渝天然气管网的基本情况,从自然灾害、管道本质安全隐患、环境安全隐患以及天然气调峰等方面,对川渝地区天然气管道存在的安全问题进行了分析,并对加强管道安全保护提出了相应对策。

我国公共定价管制研究——以输配电价管制为例

尽管公共定价不涉及政府对经济的直接调控,但科学管制公共定价同样关系到资源配置效率、收入分配公平以及财政收支规模等重要问题,因此对公共定价管制进行研究,对于推进我国现阶段市场经济体制中的公共企业改革、政府职能转变及经济结构调整有着重要意义。在此背景下,以输配电价管制为例对我国公共定价管制进行研究,尝试为政府管制放松浪潮背景下我国公共定价管制机制改革提出可行的改革思路、路径及政策建议。

兰州煤气管网的可利用性分析

城市配气管网作为输气管道的下游配套工程,是天然气顺利进入沿线城市的重要环节。在利用原有的煤气管网的基础上,根据城市燃气管网系统的特点,在进行天然气置换前需要对原有的煤气管网进行分析与改造。以兰州煤气管网为例,通过对输配系统设计、施工以及防腐的分析,对煤气管网在土壤电阻率和腐蚀性、管道外防腐层以及管内壁等方面进行检测提出了建议。

淮苏沪交流特高压线路无功电压特性分析

了解交流特高压线路的无功电压特性对电网的安全稳定运行至关重要。利用BPA软件搭建淮南—南京—上海特高压潮流等值系统,对线路的感性无功补偿度、高峰和低谷方式下无功平衡情况进行分析;计算出反映输电能力和无功平衡状态分界点的自然功率及广义自然功率;分析输电线路在不同运行方式下的沿线电压分布特性。计算结果表明:特高压输电线路的无功补偿充足,满足高峰和低谷方式下的无功需求;广义自然功率约为自然功率的28.65%~100%;在5中不同运行方式下沿线电压幅值的最大值出现在泰州站和苏州站之间且电压能够控制在合理的范围内。淮苏沪特高压交流输变电工程的无功资源配置情况,满足其安全稳定运行的要求。