共查询到19条相似文献，搜索用时 140 毫秒
1.
基于常规孔渗测试、核磁共振、扫描电镜等分析,研究了沁水盆地南部煤储层孔隙-裂隙系统发育特征及其对渗透率的贡献。结果表明,煤样孔隙结构以吸附孔为主,渗流孔发育相对较差,可动流体孔隙度很小;多数煤样A类和B类较大裂隙所占比例不高,C类和D类较小裂隙较为发育;大孔孔隙度和微裂隙发育程度对渗透率影响最大。但本区煤样大孔孔隙度低,裂隙多被矿物充填,孔隙、裂隙之间连通性较差,对煤储层渗透率的贡献较小;多期发育的宏观构造裂隙可能对煤储层渗透性起到一定的改善作用。 相似文献
2.
采用扫描电镜、压汞试验、等温吸附实验分析贵州金佳矿区8个主要煤层孔隙发育特征。煤储层发育较多的原生孔、气孔及张性裂隙,次生孔隙主要为粒间孔,矿物溶蚀孔、矿物铸模孔相对较少;压汞试验表明,3#煤层开放孔较多,压汞曲线为Ⅱ型,孔隙连通性较好; 1#、7#煤层以微小孔为主,压汞曲线为Ⅰ型,孔隙连通性中等;其余煤层压汞曲线为Ⅲ型,孔隙连通性差;煤储层孔隙度、孔容、比表面积与变质程度呈正相关;甲烷等温吸附实验显示3#、24#煤甲烷吸附速率快,吸附能力最强;矿区煤储层孔隙结构对甲烷吸附性的影响有限;对比分析矿区3#煤层有利于煤层气的开发。 相似文献
3.
研究煤中孔隙和裂隙,对煤层气勘探开发至关重要。云南恩洪地区煤层气资源丰富,具有较好的开发前景。通过多种测试手段对该区煤层气储层的孔隙、裂隙进行了表征,分析了煤储层的孔渗特征,并探讨了煤中显微组分及不同类型的孔隙对储层孔渗性的影响。研究结果表明:恩洪地区煤层厚度大,煤级适中,微小孔发育,吸附能力强,有利于煤层气的吸附;渗流孔隙结构单一,非均质性不高,渗流能力相对较好,显微裂隙以较小微裂隙(D型)为主,定向性和连通性较差,可能造成渗流通道不连续和受阻等问题,导致渗透性变差,对将来煤层气的开发产生不利影响。 相似文献
4.
不同变质变形煤储层包括低煤级、中煤级和高煤级变质变形环境中的脆性变形煤、韧性变形煤和过渡型变形煤,不同变质、变形程度和机制对煤层气的吸附/解吸影响较大。干燥煤和平衡水煤的甲烷吸附量随变质程度的增强呈现出不同的变化趋势,干燥煤呈横"S"形且易于解吸,而平衡水煤呈倒"U"字形且吸附/解吸强度皆低于干燥煤样,且解吸过程较干燥煤滞后。构造变形导致煤的大分子结构和纳米级孔隙发生不同程度的改变,进而影响气体的吸附/解吸能力,脆性变形主要增加煤的大、中孔,其基本结构单元堆砌度略有增大,甲烷吸附/解吸程度有所增强;韧性变形主要增加煤的微孔-超微孔,其基本结构单元堆砌度增加较快,煤层气吸附能力增强,降压时韧性变形煤比脆性变形煤具有较高的瞬时解吸速率。由此可见,不同变质变形环境中的煤储层吸附/解吸能力差异较大,这主要是由煤储层内部结构及其影响因素对其制约所决定的。 相似文献
5.
构造煤特有的孔裂隙系统决定了其不同类型具有独特的储层物性,而以脆性变形为主的碎裂煤发育区是煤层气勘探的有利区。根据贵州发耳煤矿9件煤样的显微镜观测和压汞实验数据,分析了构造煤微观变形和显微裂隙分形特征,进而对煤样孔隙渗透特征进行了研究。结果表明:碎裂煤显微裂隙信息维数分布在1.2~1.8;以信息维数为指标,可将碎裂煤划分为3类,信息维数分布范围分别为1.2~1.4、1.4~1.7和1.7~1.8;脆性构造变形增加了孔隙系统中大孔和中孔的孔容,构造变形越强烈,脆性系列构造煤的渗透性能越好。 相似文献
6.
为了定量表征两淮煤田(淮南和淮北煤田)煤储层吸附孔孔隙结构特征,基于低温氮气吸附实验数据及FHH模型计算了吸附孔分形维数D_1(相对压力0~0.5)和D_2(相对压力0.5~1),讨论了分形维数与孔隙结构、物质组成以及煤变质程度之间的关系。结果表明,研究区煤样低温氮气吸附回线可以划分为3类:Ⅰ类,孔隙以"墨水瓶"或"细瓶颈"形孔为主,煤样具有比表面积大、平均孔径小的特点;Ⅱ类,孔隙多为开放性较好的平行板状孔,煤样比表面积和总孔体积较低;Ⅲ类,孔隙以狭缝形孔为主,煤样总孔体积和平均孔径较大。D_1与比表面积呈较强的正相关关系,代表孔表面积分形维数,D_2和平均孔径、微孔含量分别呈高度的线性正相关和负相关,代表孔结构分形维数,不同吸附脱附曲线类型煤样的分形维数D_1呈现出Ⅰ类Ⅲ类Ⅱ类的规律,D_2则呈现出Ⅰ类Ⅱ类Ⅲ类的规律,D_1、D_2与水分、灰分均呈正线型相关,与煤的R_(o,max)的关系并不明显。 相似文献
7.
8.
煤的孔隙-裂隙结构特征是研究储层渗透性的关键问题。为了定量描述孔隙-裂隙结构的复杂程度,以黄陇侏罗纪煤田永陇矿区郭家河井田原生结构煤和碎裂结构煤为研究对象,基于压汞实验数据和扫描电镜（SEM）图像,采用Menger分形模型和计盒维数方法,分别计算不同煤体结构煤的孔隙-裂隙分形维数;同时采用不同孔径段的孔隙体积比作为权重值,计算得到孔隙综合分形维数,探讨孔隙-裂隙结构分形维数和渗透率之间的关系。研究结果表明,脆性构造变形作用对孔隙整体复杂性,裂隙孔、渗流孔复杂性以及微观裂隙复杂程度均具有积极改造作用,对吸附孔结构复杂性具有均一化作用;微观裂隙分形维数与渗透率具有较高非线性关系,脆性构造作用改造下形成的碎裂煤,其具有的孔隙-裂隙结构优势配比是决定储层高渗透性的关键。因此,建议优先考虑弱脆性变形的碎裂结构煤为主体的断层、向斜和背斜区域进行煤层气抽采。 相似文献
9.
基于低温氮吸附以及压汞实验,系统地研究了安鹤煤田二_1煤孔隙结构特征,分析了煤储层孔隙特征对该区煤层气开采的影响。研究结果表明:安鹤煤田煤储层中的孔隙以微、小孔(100 nm)为主,中、大孔(100 nm)其次。煤样的低温液氮吸附回线可以划分为3类,孔隙类型主要为开放的、连通性好的细瓶颈(墨水瓶)状孔,部分为一端封闭的不透气性孔。相比于华北其它地区,安鹤煤田煤储层的BET比表面积较大,总孔体积和孔隙度较小,且进汞饱和度中等,退汞效率相对较好。压汞曲线可以划分为两种类型,其反映的孔隙连通性均较好。结合低温液氮吸附和压汞实验,并对比华北其它地区,可知安鹤煤田煤储层的孔隙结构较利于煤层气解吸-扩散-渗流,可以作为华北地区煤层气勘探开发的优先选择。 相似文献
10.
从煤岩煤质、含气性、吸附特征、裂隙发育及渗透性等方面对湘中下石炭统测水组煤层气储层(煤储层)特性进行论述。研究表明煤储层为明显的富镜质组煤,随温度、压力的增加吸附量增大。区内煤层最大含气量为41.91m3/t,以新化芦毛江至金竹山一带为中心,包括芦毛江、冷水江、渣渡、金竹山等矿区,高富集区基本呈东西向展布。但受煤阶的影响,煤层内生裂隙发育程度明显低于龙潭组煤层,同时由于煤层煤体结构连通性差以及多起构造运动形成细小的煤粉常充填于构造裂隙中,降低了煤层的渗透性。针对上述煤储层特点,指出加强对具有上封下开裂隙系统以及原生结构煤和碎裂煤整层发育地区的煤层气勘探尤为重要。 相似文献
11.
GUO Chen QIN Yong MA Dongmin XIA Yucheng BAO Yuan CHEN Yue LU Lingling 《《地质学报》英文版》2020,94(2):243-252
The methods of nuclear magnetic resonance(NMR)spectroscopy,mercury injection porosimetry(MIP),and gas-water relative permeability(GWRP)were used to reveal the pore structure and permeability characteristics of high-rank coal reservoirs in the Bide-Santang basin,western Guizhou,South China,to provide guidance for coalbed methane(CBM)exploration and exploitation and obtain direct insights for the development of CBM wells.The results indicate that the coal reservoirs in the study area are characterized by well-developed adsorption pores and poorly developed seepage pores.The bimodal NMR transverse relaxation time(T2)spectra and the mutation in the fractal characteristic of the MIP pore volume indicate poor connectivity between the adsorption pores and the seepage pores.As a result,the effective porosity is relatively low,with an average of 1.70%.The irreducible water saturation of the coal reservoir is relatively high,with an average of 66%,leading to a low gas relative permeability under irreducible water saturation.This is the main reason for the low recovery of high-rank CBM reservoirs,and effective enhanced CBM recovery technology urgently is needed.As a nondestructive and less time-consuming technique,the NMR is a promising method to quantitatively characterize the pores and fractures of coals. 相似文献
12.
The Panguan Syncline contains abundant coal resources,which may be a potential source of coalbed methane.In order to evaluate the coalbed methane production potential in this area,we investigated the pore-fracture system of coalbed methane reservoirs,and analyzed the gas sorption and seepage capacities by using various analytical methods,including scanning electron microscopy（SEM）,optical microscopy,mercury-injection test,low-temperature N2 isotherm adsorption/desorption analyses,lowfield nuclear magnetic resonance and methane isothermal adsorption measurements.The results show that the samples of the coal reservoirs in the Panguan Syncline have moderate gas sorption capacity.However, the coals in the study area have favorable seepage capacities,and are conductive for the coalbed methane production.The physical properties of the coalbed methane reservoirs in the Panguan Syncline are generally controlled by coal metamorphism:the low rank coal usually has low methane sorption capacity and its pore and microfractures are poorly developed;while the medium rank coal has better methane sorption capacity,and its seepage pores and microfractures are well developed,which are sufficient for the coalbed methane’s gathering and exploration.Therefore,the medium rank coals in the Panguan Syncline are the most prospective targets for the coalbed methane exploration and production. 相似文献
13.
构造煤是在构造应力作用下,煤体发生变形或破坏的一类煤,在世界主要产煤国家皆有分布。构造变形不同程度的改变着煤的大分子结构和化学成分,而且也影响到构造煤的纳米级孔隙结构(<10 0 nm ) ,它是煤层气的主要吸附空间。通过构造煤显微组分和镜质组油浸最大反射率的测定,采用液氮吸附法对不同变质变形环境、不同变形系列构造煤的纳米级孔隙分类、孔隙结构特征进行了深入系统的研究,并结合高分辨透射电子显微镜和X射线衍射对大分子结构和孔隙结构的分析,结果表明:不同类型构造煤纳米级孔径结构自然分类,可将孔径结构划分为过渡孔(15～10 0 nm )、微孔(5～15 nm )、亚微孔(2 .5～5 nm )和极微孔(<2 .5 nm ) 4类。低煤级变形变质环境中随着构造变形的增强,不同类型构造煤过渡孔孔容明显降低,微孔及其下孔径段孔容明显增多,可见亚微孔和极微孔,过渡孔的比表面积大幅度降低,而亚微孔的却增加得较快。从脆韧性变形煤至韧性变形煤,总孔体积、累积比表面积、N2 吸附量随着构造变形的增强,这些结构参数均迅速增加,但中值半径进一步下降。非均质结构煤孔隙参数与弱脆性变形煤相当。中、高煤级变形变质环境形成的各种类型构造煤与低煤级变质变形环境相比,孔隙参数的变化基本一致。但不同类型构造煤的变化又有所区别 相似文献
14.
为了探讨中-高煤级深部煤层孔隙结构特征和吸附性,以陕西宜川和山西柿庄地区埋深100~1 800 m的中-高煤级样品为研究对象,对样品进行了煤岩煤质分析以及压汞法、核磁共振、低温液氮和等温吸附等测试,结果表明：(1)随着深度的增加,煤层吸附孔含量增多,渗流孔含量减小,渗透性降低,储层物性变差。(2)比表面积和总孔体积在1 000 m附近出现高值区域,随后才出现如前人所述的随深度逐渐降低的趋势,这与小孔的贡献率一致,可见比表面积和总孔体积并非完全由微孔决定,小孔作用显著。(3)深部煤层吸附性是压力的正效应与温度的负效应共同作用的结果,随着压力的增高,吸附量明显增加,温度每升高1 ℃,吸附量平均减少0.25 cm3/g;兰氏压力并不是简单地随温度递增而递增,而是存在随温度变化的拐点(35 ℃),大于拐点温度时,兰氏压力才呈现增高趋势。 相似文献
15.
The Classification and Model of Coalbed Methane Reservoirs 总被引：8，自引：0，他引：8
SU Xianbo LIN Xiaoying SONG Yan ZHAO Mengjun Henan University of the Sciences Jiaozuo Henan Research Institute of Petroleum Exploration Development PetroChin Beijing 《《地质学报》英文版》2004,78(3):662-666
Coalbed methane has been explored in many basins worldwide for 30 years, and has been developed commercially in some of the basins. Many researchers have described the characteristics of coalbed methane geology and technology systematically. According to these investigations, a coalbed methane reservoir can be defined: "a coal seam that contains some coalbed methane and is isolated from other fluid units is called a coalbed methane reservoir". On the basis of anatomization, analysis, and comparison of the typical coalbed methane reservoirs, coalbed methane reservoirs can be divided into two classes: the hydrodynamic sealing coalbed methane reservoirs and the self-sealing coalbed methane reservoirs. The former can be further divided into two sub-classes: the hydrodynamic capping coalbed methane reservoirs, which can be divided into five types and the hydrodynamic driving coalbed methane reservoirs, which can be divided into three types. The latter can be divided into three types. Currently, hydrodynamic s 相似文献
16.
构造煤中煤层气扩散-渗流特征及其机理 总被引：2，自引：0，他引：2
煤层气产出一般要经过解吸、扩散和渗流三个阶段,而煤层气在变形较强的构造煤中的扩散过程不同于在原生结构煤或变形较弱的煤体中的扩散。外界压力的变化只是构造煤吸附与解吸整个过程的一种外在因素,构造煤的变形和结构变化以及吸附势场的转换才是构造煤吸附与解吸的内在因素,是导致解吸过程不可逆性的根本原因。当构造煤体与CH4等多元气体间的吸附平衡状态遭到破坏时,变形较强的构造煤在降压后会产生解吸滞后现象;而变形较弱的煤,分子结构中的气体会很快解吸,第一阶段是气体解吸作用,第二阶段是游离气体从微孔向较大孔隙扩散的过程,气体扩散速率主要由第二阶段决定。构造煤气体扩散机理主要是由孔隙形状、大小、连通性和多元气体性质和状态所决定的。韧性变形煤的微孔隙比较发达,所以韧性变形煤以Knudsen扩散为主,脆性变形煤的中、大孔隙所占比例较大,而且脆性变形煤的孔隙之间具有很好的连通性,所以脆性变形煤以Fick型扩散为主,脆-韧性变形煤以及接近脆-韧性变形煤的脆性变形煤和韧性变形煤均以过渡型扩散为主。在试井渗透率比较中,一定变形程度的脆性变形煤>韧性变形煤,脆性变形煤中以过渡孔为主,其余为微孔,测不出亚微孔和极微孔,脆性变形还增加了各孔隙之间的相互连通性。韧性变形煤中过渡孔比表面积所占比例下降,微孔和亚微孔增高,扩散主要发生在微孔和过渡孔中,所以韧性变形煤的试井渗透率低于脆性变形煤的试井渗透率。 相似文献
17.
煤中矿物可以影响煤储层物性,进而影响煤层气的开发。运用光学显微镜和扫描电镜研究沁水盆地南部煤中矿物的种类、含量和赋存特征。基于煤储层的平衡水等温吸附实验和压汞实验,研究了沁南地区煤中矿物对煤储层吸附性能和孔渗性能的影响。结果表明,柿庄北区块3号和15号煤平均矿物含量分别为10.68%和12.81%,且15号煤硫化物含量较高。扫描电镜下可观察到充填煤储层胞腔孔、粒间孔隙和微裂隙的方解石、黄铁矿、高岭石和石英。孔隙度和渗透率以及兰氏体积和煤中大中孔比例均随灰分产率的增加而减小,表明煤中矿物的存在会降低煤储层的吸附性能和孔渗性能,煤储层中矿物充填主要影响煤的大中孔和裂隙,影响煤层气在割理和裂隙中的渗流,导致孔隙度和渗透率下降,而少量粘土矿物充填微孔可导致煤的吸附性能下降。 相似文献
18.
19.
The majority of coalbed methane(CBM) in coal reservoirs is in adsorption states in coal matrix pores. To reveal the adsorption behavior of bituminous coal under high-temperature and high-pressure conditions and to discuss the microscopic control mechanism affecting the adsorption characteristics, isothermal adsorption experiments under hightemperature and high-pressure conditions, low-temperature liquid nitrogen adsorption-desorption experiments and CO2 adsorption experiments were performed on coal samples. Results show that the adsorption capacity of coal is comprehensively controlled by the maximum vitrinite reflectance(Ro, max), as well as temperature and pressure conditions. As the vitrinite reflectance increases, the adsorption capacity of coal increases. At low pressures, the pressure has a significant effect on the positive effect of adsorption, but the effect of temperature is relatively weak. As the pressure increases, the effect of temperature on the negative effect of adsorption gradually becomes apparent, and the influence of pressure gradually decreases. Considering pore volumes of pores with diameters of 1.7-100 nm, the peak volume of pores with diameters 10-100 nm is higher than that from pores with diameters 1.7-10 nm, especially for pores with diameters of 40-60 nm, indicating that pores with diameters of 10-100 nm are the main contributors to the pore volume. The pore specific surface area shows multiple peaks, and the peak value appears for pore diameters of 2-3 nm, indicating that this pore diameter is the main contributor to the specific surface area. For pore diameters of 0.489-1.083 nm, the pore size distribution is bimodal, with peak values at 0.56-0.62 nm and 0.82-0.88 nm. The adsorption capability of the coal reservoir depends on the development degree of the supermicroporous specific surface area, because the supermicroporous pores are the main contributors to the specific pore area. Additionally, the adsorption space increases as the adsorption equilibrium pressure increases. Under the same pressure, as the maximum vitrinite reflectance increases, the adsorption space increases. In addition, the cumulative reduction in the surface free energy increases as the maximum vitrinite reflectance increases. Furthermore, as the pressure increases, the surface free energy of each pressure point gradually decreases, indicating that as the pressure increases, it is increasingly difficult to adsorb methane molecules. 相似文献