Morphology and Propagation of Hydraulic Fractures for CBM Wells

Objective As the most widely used and effective technique in reservoir reconstruction of unconventional natural gas,hydraulic fracturing has been achieved good effect in CBM development.It is important to note that coal seam is both source rock and reservoir,

Calculation of dynamic loads of the sucker rod pumping system in CBM wells

The mathematical model of dynamic loads was developed based on an analysis of the polished rod load of beam pumps, and the variation of the dynamic loads and the computation of the minimum and maximum limits during a complete pumping cycle were given out by solving the model.Field examples verify that it is necessary to take into account the inertial and vibration loads while calculating polished rod loads.During the prophase of the pumping production, the dynamic to polished rod load ratio is relatively large.Then the ratio decreases rapidly and becomes small after entering stable production.Moreover, the total deformation of rod and tubing in CBM wells is much smaller than that in oil fields, and the deformation caused by the dynamic loads is also relatively small.The result of this work is the calculation of the dynamic loads.The application of this calculation for the sucker rod pumping system in CBM wells can give the desired accuracy of polished rod load and the dynamometer cards, which provides a reasonable basis for the design and selection of beam pumps.

The influence of high-yield-water characteristics on productivity of CBM wells and expulsion and production method carried out in Yanchuannan block of the Ordos basin, China

In order to further study the influence of high-yield-water on the productivity of CBM （coalbed methane） wells and the expulsion and production method carried out in CBM wells, by means of analyzing and researching production characteris- tics and geologic condition of the CBM wells with high water yield in Yanchuannan block located at the eastern margin of Or- dos basin, the mechanism of high water yield decreasing the productivity of CBM well was discussed, and the expulsion and production method for this type of CBM well was proposed. The results show that high water yield would decrease the produc- tivity of CBM wells, and the mechanism is： first, in some circumstances, high water yield could reflect that there was dissipa- tion during the process of coalbed methane reservoir forming, which would lower the gas saturation of coal gas reservoir and reduce the productivity of CBM well; second, a large quantity of coalbed methane dissipated in the form of solution gas, caus- ing the practical reservoir pressure when gas appeared in casing to be lower than critical desorption pressure of the coal bed; finally, the CBM well with high water yield would have higher requirements of discharge and mining installation, system and continuity, and any link with problems would have a great impact on the well＇s productivity and would increase the difficulty of discharge and mining. In the case of wells with high water yield, the key is to select applicable discharge and mining installa- tion, which should be able to make the bottom hole flowing pressure decline smoothly and fast, and make the wells produce gas as quickly as possible but able to slow down the rate of discharge and mining properly when gas has appeared. In addition, in view of the CBM wells with high water yield, an installation lectotype method based on Darcy＇s law was proposed, which was found with good accuracy and practicability through field application.

Interlayer interference mechanism of multi-seam drainage in a CBM well:An example from Zhucang syncline

Based on the characteristics of the strong volatility of physical property in vertical direction, high gas content, high resource abundance and large exploitation potentiality of coal reservoir in Bide-Santang basin of Zhina coal field, we study the generation mechanism of interlayer interference, propagation rules of reservoir pressure drop and influencing factors of gas productivity in CBM multi-seam drainage in the paper. On the basis of the actual production data of X-2 well of Zhucang syncline in Bide-Santang basin,by simulating the gas production process of a CBM well under the condition of multiple seam with COMET3 numerical simulation software, we analyze the influencing factors of gas productivity during the process of multi-seam drainage, and illuminate the interlayer interference mechanism of multiseam drainage. The results show that permeability, reservoir pressure gradient, critical desorption pressure and fluid supply capacity of stratum have great influence on gas productivity of multi-seam drainage while coal thickness has little influence on it. Permeability, reservoir pressure gradient and fluid supply capacity of stratum affect the propagation velocity of reservoir pressure drop and thereby affect the final gas productivity. Moreover, the influence of critical desorption pressure on gas productivity of multiseam drainage is reflected in the gas breakthrough time and effective desorption area.

Characteristics of microbial communities in water from CBM wells and biogas production potential in eastern Yunnan and western Guizhou, China

The study of microbial communities in the produced water of coalbed methane(CBM)wells is an important aspect of microbial-enhanced methane production.Water produced from 15 CBM wells in four synclines in eastern Yunnan and western Guizhou was collected.Through the use of 16S ribosomal RNA(16S rRNA)amplicon sequencing and realtime fluorescence quantitative polymerase chain reaction(PCR),the characteristics of bacterial and archaeal communities before and after enrichment culture were studied.The methanogenic pathways of secondary biogas were discussed,and potential microbial-enhanced methane production was preliminarily evaluated.The results showed that the bacterial DNA content in uncultured produced water was low,so it is difficult to detect.After enrichment,the dominant bacteria phyla were Proteobacteria,Bacteroidetes,and Firmicutes.A total of seven phyla were detected in the uncultured produced water,and the dominant archaeal phylum was Euyarchaeota.Methanogens were the main component of archaea.The dominant archaeal genera were Methanobacterium,Methanoculleus and Methanobrevibacter.The community structure of the archaea changed noticeably after four days of enrichment culture.The relative abundance of Euryarchaeota increased to 99%in most samples after enrichment culture.It was found that there was a transition from Methanoregula to Methanobacterium within genera.The relative abundance of Methanobacterium increased,which can produce hydrogenotrophic methane.Combined with the isotopic composition of the produced water and gas,it is considered that the CBM in the Tucheng and Enhong synlines consists of a mixture of thermogenic gas and biogas.The proportion of secondary biogas in the Tucheng and Enhong synlines are estimated to range from 10.89% to 49.62%.There are mainly hydrogentrophic methanogens in the study area,and CO_(2) reduction is the main way of microbial gas production.After enrichment culture of produced water in the study area,the hydrogenotrophic methanogens were enriched.These two areas have strong potential for microbial-enhanced methane production.

生孢噬纤维菌内切葡聚糖酶的异源表达及CBM6对其酶学性质的影响

内切葡聚糖酶是纤维素酶系的重要组分之一,但大部分内切葡聚糖酶酸碱耐受性较差。为挖掘新型内切葡聚糖酶,本研究从生孢噬纤维菌CX11基因组中克隆了一个内切葡聚糖酶基因Sm_1350。该基因大小为2 196 bp,编码732个氨基酸,编码蛋白包含一个分泌信号肽、GH5催化结构域、6家族碳水化合物结合模块(CBM6)和一个C末端结构域(CTD)。利用实时荧光定量PCR技术对Sm_1350在不同碳源条件下的相对表达水平进行了分析,结果表明,Sm_1350在纤维二糖和滤纸培养基中的表达水平均显著高于在葡萄糖培养基中的表达水平,推测其在CX11降解纤维素过程中发挥一定作用。本研究构建了Sm_1350及其3种截短突变体,分别为Sm_1350、Sm_1350-GH5-CBM6、Sm_1350-GH5和Sm_1350-CBM6,并在大肠杆菌中进行异源表达。结果表明,去除CTD结构域明显提高了目的蛋白的可溶性表达水平。以CMC为底物时,Sm_1350-GH5-CBM6与Sm_1350-GH5酶活力分别为(7 000.00±50.00)U/g和(2 542.73±35.03)U/g,表明去除CBM6降低了Sm_1350-GH5对可溶性多糖的水解能力。酶学性质分析结果显示,Sm_1350-GH5-CBM6与Sm_1350-GH5均有较好的pH稳定性,去除CBM6结构域只改变了Sm_1350-GH5的最适温度,对最适pH以及温度稳定性没有产生影响。此外,Sm_1350-CBM6具有较强的几丁质结合能力,在蛋白纯化方面具有良好的应用前景。

Geochemical characteristics of produced fluids from CBM wells and their indicative significance for gas accumulation in Daning-Jixian block,Ordos Basin

The Daning-Jixian block,the eastern edge of the Ordos Basin,is one of the most potential areas for CO_(2)geological storage,enhanced coalbed methane recovery(ECBM)exploration and production in China in recent decades.The ionic composition and total dissolved solids(TDS)of the produced water,coal organic matter maturity,molecular composition and carbon isotope characteristics of the produced gas were utilized to analyze the hydrogeological condition,CBM generation and migration characteristics in this area.The CBM enrichment patterns and the geological impacts on gas well production characteristics were revealed.The optimal area for CBM development and CO_(2)geological storage in the study area were also proposed.Dominated by the Xueguan reverse fault zone,the hydraulic unit in this area can be divided into two parts(i.e.,the recharge-runoff zone in the east and the weak runoff-stagnation zone in the west).The thermogenic gas is dominating CBM genesis in this area.Secondary biogenic gas replenishment is only distributed in the eastern margin area,where theδ13C1 value is less than the thermal simulation results as an influence of hydrodynamic fractionation.Finally,two models of CBM formation and accumulation were proposed,1)thermogenic CBM migrated by hydrodynamic and resorbed for preservation at impermeable fault boundaries;2)thermogenic CBM trapped by fault and accumulated by hydrodynamic in slope zone.The gas production performance,generally increased from east to west,is mainly dominated by hydrogeological conditions.Generally,the west side of the fault zone is the enrichment and high-yield area for ECBM development and CO_(2)geological storage in the study area.

基于CBM的共用信息系统装备维修保障体系分析与架构设计

随着信息化和数字化技术的不断发展,企业和组织之间信息共享和协作的迫切需求驱使着共用信息系统的产生。企业和组织可以通过共用信息系统装备实现资源的共享和互通,避免信息孤岛和资源浪费,提高信息协同和决策效率。然而环境、人为等因素会导致共用信息系统装备出现故障,使系统无法正常工作。虽然已有相应的装备维修体系,但针对共用信息系统的装备维修方法落后,架构老旧且维修可扩展性低。为解决该问题,以基于状态的维修理论(CBM)为基石,结合模糊理论、灰色模型以及现有共用信息系统维修体系,分析基于CBM的共用信息系统维修保障体系所需功能和流程,构建基于CBM的全新共用信息系统装备维修架构。所提出架构优化了传统装备维修保障模式,为维修管理工作提供了科学的参考依据。

Calculation model for water influx and controlled reserves for CBM wells with high water yield

Compared with conventional gas reservoir,percolation mechanism of coalbed methane(CBM)is completely different,it is remarkably affected by adsorption/desorption performance,pressure variation and coalbed characteristics.Then it is difficult to calculate the controlled reserves of CBM wells.Moreover,the connection of edge-bottom water or interbedded water by fractures or faults may largely increase the water yield and drainage period,leading to obvious water invasion in some CBM wells.There are few literature about the predicted production for CBM wells with high water yield.Focusing on the unconventional CBM reservoir,methods of pseudo geological reserves and production index curves are adopted to establish the calculation model of water influx and controlled reserves.It further confirms that the calculation model is successfully applicated on the CBM wells at the middle part of Qinshui Basin in China.

The Application of Well Logging to CBM Exploration

Well logging technology in coalbed methane （CBM） exploration may develop in two directions： one is the novel well logging methods; the other is the new interpretation methods for the conventional logging data, on which the authors of this paper concentrated mainly. The paper introduced several methods in calculating with well logs such important parameters as porosity, permeability and gas content of CBM reservoir and evaluated their effectiveness. A new method of well logging data interpretation was put forward for coalbed recognition, i.e., the combination of the principal component analysis and the wavelet transform. The authors find that the second principal component （PCA2） contains much more information of coalbed in the coal-bearing series and the reconstruction signal from the detailed wavelet coefficients at level 4 （PCA24） and 5 （PCA25） highlights the signature ofcoalbeds. In terms of the characteristics of CBM reservoir in China, the authors summarized the key points in the application of well logging technique to CBM exploration, and gave a guideline for further related research work.

深层煤岩气水平井各段产出贡献及其主控因素——以鄂尔多斯盆地东缘大宁-吉县区块为例

在“双碳”目标背景下,实现深层煤岩气高效开发、甲烷管控或近零排放具有极其重要的战略意义。但深层煤岩气水平井各段产出贡献不清、主控因素不明,制约了煤层气单井产能提升和降本增效。为此,以鄂尔多斯盆地东缘大宁—吉县区块为例,通过示踪剂监测技术,获得了深层煤岩气水平井各段差异认识,提出了基于深层煤岩气地质—工程甜点系数的模型构建方法、“黑金”靶体和地质—工程甜点分类评价标准,构建了沿水平井地质—工程甜点模型,提取了11项地质因素和10项工程因素开展“定性+定量”评价,明确了深层煤岩气水平井各段产出贡献的主控因素。研究结果表明:①深层煤岩气水平井各井段的产出差异大,各井段产气量贡献率介于2.2%~25.3%,同一口井各井段产气量差异最高达11.5倍。②明确了影响水平井各井段产出主控因素是钻遇Ⅰ、Ⅱ类地质—工程甜点情况和压裂改造规模;钻遇Ⅰ类和Ⅱ类甜点井段长度占水平井长度的63.7%,其中采用相对更高规模压裂设计的Ⅰ、Ⅱ类甜点段仅占37.5%,却贡献了单井59.2%的累计产气量。③影响高产段的离散型因素,裂缝形态以均匀缝为主;构造曲率以正曲率和零曲率为主;煤岩类型以光亮煤和半亮煤为主。④利用斯皮尔曼相关系数法、层次分析法和梯度提升树法定量确定的主控因素,与基于甜点模型得到的认识一致。结论认为,研究成果为深层煤岩气水平井甜点评价、“黑金”靶体钻遇率提高、压裂段簇差异化设计、施工方案优化等方面提供了新认识、新方法和新思路。

黑曲霉耐热型葡聚糖酶纤维素结合结构域的替换与融合体酶性质

该文旨在通过更换纤维素结合结构域(cellulose binding domain, CBD)的方式探索获得具有纤维素水解能力的耐热型葡聚糖酶的方法。黑曲霉(Aspergillus niger)来源的葡聚糖酶AnEglA6具有优越的耐热性能,在禽类饲料生产中具有应用前景。通过更换不同家族来源的碳水化合物结合结构域(carbohydrate binding module, CBM)编码区,构建了融合体葡聚糖酶基因,分别在巴斯德毕赤酵母(Pichia pastoris)中进行异源表达。AnEglA6催化结构域与分别来源于嗜热菌(Caldicellulosiruptor kristjanssonii)和荧光假单胞菌(Pseudomonas fluorescens)的木聚糖酶的底物结合结构域CBM9、CBM10结合获得的融合体酶AnEg-CBM9和AnEg-CBM10均具有较高的纤维素水解能力,并且底物范围进一步扩大,对微晶纤维素也具有一定的水解能力。AnEg-CBM10热稳定性有显著的提高,在85℃下酶活力半衰期达到40 min左右,能短时耐受90℃高温。融合体酶AnEg-CBM10是一种热稳定性提高、具有纤维素水解能力的新型葡聚糖酶。

鄂尔多斯盆地东缘韩城区块煤层气高产井地质主控因素

鄂尔多斯盆地东缘韩城区块煤层气资源丰富,受构造地质条件影响,不同构造分区的煤层气单井产能差异较大。为明确该区块煤层气高产井地质主控因素,基于构造、煤储层特征及煤层气富集控制因素,结合气田生产数据,对煤层气高产井的地质主控因素进行了剖析。研究结果表明:(1)煤层气井产能受“构造条件、水动力条件、煤体结构”三大因素控制,其中构造条件控制煤层气富集成藏,水动力条件影响煤层气保存,煤体结构影响煤储层渗透率;(2)区块内的煤层气高产井主要分布于次级构造发育区,地层水矿化度介于(2~11)×10^(3)mg/L,原生—碎裂煤平均厚度为4.4m,单井日产气量大于1000m^(3);(3)小断层或者微构造改善了煤储层的渗透性,尤其是次级构造高部位产生的裂隙,有利于煤层气解吸渗流,有利于煤层气高产;(4)在构造活动较剧烈的条件下,大断层附近易于形成煤层气逸散通道,不利于煤层气的保存。结论认为,鄂尔多斯盆地东缘韩城区块构造运动不但造就了各种构造形态,而且使煤体结构发生了变化,不同构造形态下的水动力条件也不同,因此构造运动对韩城区块煤层气井高产起到了极为重要的控制作用;该研究成果对韩城区块的煤层气开发调整具有一定的指导意义,对地质条件类似的煤层气区块具有借鉴意义。

CBM标准化研究现状及发展趋势

基于状态的维护(CBM)是一种新的设备维护模式,建立CBM方式的设备维护系统是一个复杂的系统工程,为规范相关软硬件产品的研制开发、提高不同厂商产品的可互换性与可互操作性,IEEE、ISO、OSA-CBM、MIMOSA等组织相继制定了一些标准,对CBM技术的发展起到了很好的促进作用。本文介绍了国际上CBM标准化研究的现状及相关成果,分析了CBM标准化研究的发展趋势,介绍了作者在CBM研究方面的成果,并对我国CBM标准化研究工作提出了建议。

煤层气井同心管气体射流排采特征分析

为解决煤层气井中有杆泵排采工艺存在的埋泵、卡泵及偏磨等问题,实现产气中后期降低井底流压、释放解吸气的目的,探索煤层气井中后期低产液量情况下的排采工艺至关重要。基于可压缩性的气体介质,考虑射流泵排采工艺的技术特点,分析了煤层气井井下同心管柱气体射流泵排液原理,计算管柱环空内气携液条件,建立了同心管气体射流泵喷嘴、喉管和扩散管等流动模型,考虑气体射流的音障,分析了不同喷喉组合下的携液特征。研究结果表明:初始注入气量、压力一定的情况下,喷嘴直径越小,射流速度越大,携液量越多;但喷嘴直径越小,所需的注入气量越小,气体的流速易超过临界流速导致流体特性发生改变;当产液量为3 m^(3)/d,注气压力为6 MPa,喷嘴直径为3.50、4.02、5.00 mm时,所需的注入气量分别为9338、11225、15023 m^(3)/d。气体射流泵排液机理、气体射流特征的研究结果可为同心管气体射流泵工艺设计和现场试验提供理论依据。

我国公路桥梁管理系统(CBMS)的开发与推广应用

以我国公路桥梁管理系统 （ＣＢＭＳ） 的研究开发为背景， 阐述了 Ｗｉｎｄｏｗｓ 环境下的ＣＢＭＳ＿ Ｗｉｎ Ｖ４－０ 版的开发环境、系统构成、数据库设计、各功能模块设计、输入输出要求， 以及近年来ＣＢＭＳ 在国内各省市的推广应用情况；此外， 还简单介绍了天威ＧＩＳ （ 地理信息系统） 和桥梁动态多媒体处理技术在ＣＢＭＳ 中的应用。

CBMS在高速公路桥涵养护管理中的应用

中国公路桥梁管理系统(CBMS)为交通部"八五"计划项目,目前在公路交通系统正得到广泛推广应用,该系统对实现中国公路桥梁涵洞科学化、标准化和智能化管理具有很大的促进作用。论文简要介绍CBMS的结构层次,结合CBMS2007版在广东某高速公路桥梁涵洞养护管理中的应用实践,探讨了系统应用的不足之处,并提出了改进建议。

CBM在线文献分析功能探讨

以"文献计量学"为主题词实施检索,从作者、出版时间、发文机构、来源期刊、主题等方面介绍CBM的在线文献分析功能,探讨存在的不足并提出改进建议,包括提高数据标引规范性、增加数据清洗功能等方面。

基于CBM的军机持续适航管理

基于状态的维修CBM(Condition-Based Maintenance)是当今世界维修界影响巨大的维修方式,不仅成功应用于国外工程机械领域,也为民航飞机适航和维修工作提供了可靠的技术支撑。通过分析CBM的技术方法和实施步骤,将其与军机持续适航管理工作特点结合在一起,试图通过借鉴其在民航领域的成功来推动军机适航工作。

CBM2蛋白的高密度自诱导

为提高外源蛋白表达量,以pET20b载体、BL21(DE3)E.coli宿主细胞,比较了乳糖和IPTG对CBM2(碳水化合物结合结构域)蛋白表达量的诱导效果。ZYM-5052自诱导培养基菌体OD600是IPTG LB培养基菌体的4.4倍。SDS-PAGE显示200μL ZYM-5052菌体细胞含有82.3μg CBM2,占细胞总蛋白55.3%;等量IPTG LB菌体细胞含有16.6μg CBM2,占细胞总蛋白25.7%。取不同培养时间等量等同OD600的ZYM-5052菌体进行SDS-PAGE,结果显示单位细胞中蛋白量随着培养时间而增加。所以高密度自诱导不仅提高了细胞生长密度、而且提高了单位细胞中蛋白表达量。自诱导方案用于表达葡聚糖酶,与IPTG LB菌体相比,自诱导菌体OD600是其2.3倍,酶活性是其4.5倍。该研究为提高外源蛋白表达量提供了较为简单、普适的高密度自诱导方案。