压力控制下高煤阶储层煤层气井排采的流体效应

为得到高煤阶储层煤层气井排采的压力-产气-产水动态平衡关系,揭示不同压力控制下的煤储层煤层气井排采的流体效应及机制,以沁南地区X1和X2煤层气井为研究对象,在X1煤层气井排采阶段划分的基础上,分析了不同压力条件下的煤储层煤层气井排采解吸规律及流体效应;研究了不同排采阶段的套压、动液面高度、井底压力及枯竭压力与产能的关系;数值模拟了X2煤层气井在压力控制前后的产能变化特征。结果表明:煤层气井排采的流体效应取决于是否对排采见气初期套压进行控制,排水阶段结束后采用蹩压、控压的排采制度,可有效提高煤层气井的产能。     

沁水盆地南部煤层气井排采动态过程与差异性

针对沁水盆地南部煤储层变质变形的特点,通过对沁水盆地南部某井组的排水采气动态过程与差异性进行分析,结果表明：井组单井之间气产量变化大,排采效果差异性明显,单井产水能力不一;在煤层气井排采过程中,为防止吐砂和压敏效应,排采强度、制度调整不易过大、过频;在煤层气井排采的不同时期应采用不同的工作制度,在以排水为主的前期排采阶段,排采工作制度以控制动液面为核心来制定,在产气为主的中后期稳定生产阶段,排采工作制度以控制套压（井底流压）为核心来制定;煤层气井生产过程中,在保持一定回压确保煤储层安全的前提下,应尽可能降低套压生产,以利于煤储层平均压力的降低,扩大煤层气的解吸范围,获得高产气。     

浅析影响煤层气井产量的几个因素

分析了影响煤层气单井产量的几个因素,如瓦斯含量、井网布置、储层保护、裂隙沟通、科学排采等。包括:瓦斯含量不同,产气量不同;煤层气井网布置需结合地质构造等因素优化布置;在钻井和固井过程中需对煤储层进行保护;煤层压裂改造,可有效将井孔与煤层天然裂隙沟通起来,增加产能,增大气体解吸率;根据生产实践,进行定压排采、定产排采。     

考虑应力敏感性的煤层气井产能模型及应用分析

煤储层应力敏感性是影响煤层气井产能的地质因素,在煤层气井排采过程中如何降低或避免煤储层应力敏感性对煤层气井产量的影响是值得考虑的问题。在对煤储层应力敏感性分析的基础上,推导了考虑应力敏感性的煤层气气井产能模型,提出了用产量降低幅度值(β)描述应力敏感性对煤层气井产量的影响程度,揭示了有效应力对煤储层渗透性和煤层气井产能的影响规律。研究结果表明:煤储层渗透率随有效应力的增加按负指数函数规律降低,在煤层气开发中煤储层表现出明显的应力敏感性。考虑煤储层应力敏感性后,煤层气井的产量低于不考虑应力敏感性的气井产量;随生产压差的增大,煤层气井的产量增加幅度较小,并逐渐趋向稳定,且煤层气井产量下降幅度β值增大;煤层气井的产量降低幅度β值随应力敏感系数的增大整体呈增高趋势。随着生产压差的增加,煤层气井的产量增加幅度较小,并逐渐趋向稳定,说明放大生产压差并不能获得最大产量,煤层气开发需要制定合理的生产压差和严格控制排采强度。     

煤层气井排采过程中储层压力传播规律研究

 煤储层压力是影响煤层气产出的关键因素，查明煤储层压力在煤层气井排采过程中的传播规律对于煤层气的开发具有重要的指导意义。为此，本文在分析煤层气井排采机理的基础上，重点研究了煤储层压力在不同的煤储层边界条件和排采制度下的传播规律。研究表明：在不同的煤储层边界条件和排采制度下，储层压力传播形成的压降曲线各异；煤储层压力的传播过程可分为两个阶段，即压力传播到储层边界之前为第一阶段，传到储层边界之后为第二阶段。     

韩城煤层气田煤层气井排采精细控制模式研究

为了完善煤层气井排采模式,通过在韩城煤层气田长期的现场排采实践,在现有"两期、五阶段"煤层气井阶段排采模式的基础上,从煤储层解吸-扩散-渗流的角度分析,认为憋压排水-产能释放阶段出现套压和动液面快速波动的现象,是由于现行排采制度与高煤阶、低渗透煤储层的供流能力不完全匹配引起的。依据稳定控制井底流压压降和排采工作制度与地层供流能力相适应的基本思想,将现场采用的模式进行了修正和完善,提出了"两期、六阶段"煤层气井排采精细控制模式,现场试验表明,按照这一精细控制模式,可避免出现套压和动液面快速波动的现象,降低出砂事故率。     

铁法DT3井与沁南TL007井煤层气产能对比研究

基于我国目前煤层气产能最高的DT3井和TL007井所处的地质构造背景、煤层气排采历史和排采参数的对比分析，结合煤储层物性实验成果，发现理论计算的饱和度和临界解吸压力与实际排采不一致，指出了控制煤层气产能最关键的参数是煤储层的相对渗透率和井底压力，提出了平衡开发是煤层气产能稳定、持续的重要保证。     

恩村井田煤层气垂直井产能地质主控因素分析

查明煤层气垂直井产能的地质主控因素是较准确产能预测、资源评价的基础。根据恩村井田勘探、试井、压裂、排采阶段的资料,对煤层气开发区块内煤储层原始渗透率、含气性、水平最小与最大主应力、煤层气井平均日产水量等进行了系统分析;利用模拟软件模拟比较了在其它地质参数不变的情况下,仅改变某一参数引起的产能差异。结果表明:在产水量相对较小的地区,水平最小主应力、原始渗透率的大小对产能影响最大;产水量相对较大地区,原始储层渗透率、排液对产能影响最大,而其他参数对产能的影响不大。目前恩村区块煤层气垂直井排采的结果充分说明上述结论的正确性。     

煤层气井排采中煤储层稳定性分析方法与应用——以郑庄区块为例

煤层气井排采过程中,煤储层原始地应力场发生调整,易导致储层失稳破坏,影响煤层气井抽采效率。基于单轴应变模型,考虑基质收缩效应,推导了排采过程中煤储层地应力动态模型,揭示了地应力动态变化规律。此外,建立了排采过程中煤储层稳定性分析模型,提出了煤储层峰值强度与最大主应力的差值(H)作为煤储层稳定评价基本参数,讨论了不同应力机制下地应力动态变化对煤储层稳定性的影响。研究表明：水平主应力在排水降压阶段呈线性降低,在产气阶段受基质收缩效应的影响呈非线性下降,解吸作用越强,下降速率越快。不同应力机制煤储层失稳破坏规律不同。正断层应力机制,排水降压和产气阶段,莫尔圆半径增大,圆心右移,接近破坏包络线,煤储层可能失稳破坏,解吸作用越强,莫尔圆半径增大速率越快,越容易破坏;走滑断层应力机制,排水降压和初始产气阶段,莫尔圆半径不变,向右平移,远离破坏包络线,煤储层稳定性增强,不发生破坏,而稳定产气及衰减阶段,莫尔圆向左平移,靠近破坏包络线,煤储层稳定性减弱,可能失稳破坏;逆断层应力机制,整个排采过程莫尔圆半径不断减小,远离破坏包络线,煤储层稳定性增强,不发生破坏。结合郑庄区块地应力测试井数据,对煤储层稳定...     

新疆后峡盆地煤层气井产量影响因素分析

新疆后峡盆地煤层气井单井产量差异悬殊,单井产量控制因素不明确,采用统计分析、线性回归分析法和灰色关联数学分析法,对煤层气井单井产能影响因素进行了定量表征。基于后峡盆地煤层气井单井产能差异性,煤层气井主要被划分为了3种不同的类型;I类煤层气井储层特征好,采用较小的加砂强度和加液强度,结合较小的压降,排采效果好;III类煤层气井储层特征较差,尤其是含气量较低,采用同样的储层改造手段和排采制度较难获取好的排采效果。对筛选的22个影响煤层气井产能的因素进行定量评价分析,研究表明：含气量对煤层气井产能具有显著的控制作用,而储层改造程度和排采制度的合理制定,是煤层气井高效生产的关键。     

Market and recycling of NiMH battery

<正>Market status and future trend of NiMH battery1.Global market of small NiMH battery Global market size of small NiMH batteries declined year on year since 2011.The trend will continue to 2018,at the rate of 5%to 10%annually.Demand for small NiMH batteries will be stable gradually.Many electrical apparatuses are powered by the built-in lithium battery today,which is the main reason for the shrunk market of small NiMH batteries.But,for some products,small NiMH     

China rare earth market review

正September 1-10,2014 Affected by the National Day holiday,rare earth transaction was stagnant and the market showed a weak steady state.As there was no good news for downstream market,some products with flat demand would likely rally slightly for some time to     

Current situation and future trend of China rare earth luminescent material industry

<正>Rare earth luminescent material is one of the most important application sectors of rare earths.China enjoys the exceptional advantage to develop rare earth luminescent material for its abundant rare earth resources.After several decades'endeavor,China's rare earth luminescent material industry,headed by rare earth phosphor for lamp and LED and high efficient rare earth energy-saving light source,has been gradually developed into a scale industry.China has become a major production base of rare earth phosphor for lamps and rare earth     

China rare earth market review

正June 1~10,2014Rare earth market remained weak.Quoted price of rare earth products was similar to that in May.There was no sign of recovery in downstream market.The market of NdFeB magnetic materials and phosphor was depressed.Catalyst,polishing powder and ceramic industries remained inactive.Demand from downstream industry was soft.Consumers purchased on their needs.Suppliers had strong intention to sell.Prices of rare earth products     

2014 second batch of rare earth quota released

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Annual Report analysis of Chinese rare earth-related listed companies in 2013

<正>Chinese rare earth-related listed companies have published their 2013 annual reports.It can be understood from their reports that production and operation activities of Chinese rare earth-related companies were still heavily affected by macro economy and industrial policies.They basically followed the steps of national economy.In 2013,world economy recovered slowly but the economy     

Market opportunities and challenges for rare earth polishing powder

正1.Status of rare earth polishing powder Rare earth polishing powder with high content of cerium oxide began to replace iron oxide for glass polishing and became one of the key materials in glass polishing process since 1940.Compared with traditional iron oxide,rare earth polishing powder has many advantages,such as fast polishing rate,high polishing quality and long service life.It can achieve good surface quality and improve operation conditions.For example,in lens polishing,the polishing work that cerium     

Baotou Research Institute of Rare Earths developed a new RE alloy preparation technology

正Pyrometallurgy Laboratory of Baotou Research Institute of Rare Earths had independently developed a new preparation technology of rare earth alloy for NdFeB.The alloy can remarkably enhance the coercivity of NdFeB magnet but also evidently reduce the production cost of the magnet.The new master alloy was prepared in the kA pilot-scale electrolytic cell by the independent technology.The rare earth master alloy can be used as the raw material for NdFeB.Compared     

China rare earth market review

正November 21~30,2014Due to weak demand from downstream industries,transactions of rare earth in Chinese domestic market were inactive.It was difficult to sell any rare earth products except for dysprosium oxide and terbium oxide.Suppliers lost confidence in recent market.Demand for rare earth products was soft.Consumers continued to take a wait-and-see attitude.Rare earth export market remained slow.     

Galaxy Magnets achieved the net profit of 34.02 million yuan in the first six months of 2014

正Galaxy Magnet announced its financial results for the first half of 2014 on August 14.For the first six months ended on 30 June 2014,Galaxy Magnet achieved operation income of RMB 182.3 million,up8.40% over the same period of 2013,and the net profit attributable to the shareholders of the listed company of 34.02 million yuan,increasing 35.49% over the same period of last year.Stable performance increase was led by development of new customers and application market of magnets.