木里盆地侏罗系煤层气主控因素及成藏模式

引用本文

田亚, 杜治利, 张文龙, 陈夷. 木里盆地侏罗系煤层气主控因素及成藏模式[J].中国地质调查, 2019,6(4): 88-94.
TIAN Ya, DU Zhili, ZHANG Wenlong, CHEN Yi. Main controlling factors and accumulation model of Jurassic coalbed methane in Muli Basin[J].Geological Survey of China, 2019,6(4): 88-94. 复制到剪切板

doi: 10.19388/j.zgdzdc.2019.04.12

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木里盆地侏罗系煤层气主控因素及成藏模式

田亚¹, 杜治利¹, 张文龙², 陈夷¹

1.中国地质调查局油气资源调查中心,北京 100083

2.青海煤炭地质一〇五勘探队,西宁 810001

第一作者简介: 田亚(1987—),女,工程师,主要从事石油地质方面的研究。Email: 498547751@qq.com。

收稿日期: 2019-04-22

基金资助: 中国地质调查局“武威-民乐盆地油气基础地质调查(编号: DD20160171)”“新疆塔里木、准噶尔外围油气战略选区调查(编号: DD20160203)”和“河西走廊盆地群油气资源战略选区调查(编号: 资[2015]XQ-2015-01-03)”项目联合资助

摘要

我国天然气需求逐年上升,寻找常规天然气的接替能源已迫在眉睫。木里盆地中—下侏罗统煤炭资源丰富,煤层厚度大,煤层气资源潜力巨大。综合利用野外地质调查、样品分析测试、煤炭钻井录井及含气量现场解吸,对木里盆地木里组煤层赋存特征、成藏地质条件、主控因素及煤层气成藏模式进行了研究,结果表明: 木里盆地煤层厚度大,埋藏适中,以气煤和焦煤为主,整体处于中—高变质阶段,含气量较高,煤层气资源潜力良好; 煤层的变质程度及顶、底板的封盖能力控制了煤层气的富集; 木里盆地侏罗系煤层气主要有宽缓向斜富集和大型单斜构造富集2种成藏模式。煤层气主控因素分析及成藏模式研究为后续开展木里盆地的煤层气勘探开发提供了借鉴和依据。

关键词: 木里盆地; 侏罗系; 煤层气; 成藏模式

中图分类号:P618.13;TE132.2 文献标志码:A 文章编号:2095-8706(2019)04-0088-07

Main controlling factors and accumulation model of Jurassic coalbed methane in Muli Basin

TIAN Ya¹, DU Zhili¹, ZHANG Wenlong², CHEN Yi¹

1. Oil & Gas Survey, China Geological Survey, Beijing 100083, China

2. Qinghai Bureau of Coal Geology 105 Team, Xining 810001, China

Abstract

The demand for natural gas is increasing yearly, therefore it is urgent to find an alternative energy for conventional natural gas. The Middle-Lower Jurassic in Muli Basin is rich in coal resources with thick coalbeds and huge coalbed methane potential. In this paper, field geological survey, sample analysis tests, drilling and logging data and gas content on-site analysis were used to study the occurrence characteristics, reservoir conditions, main controlling factors and coalbed methane accumulation models of Muli Formation in Muli Basin. The results show that the thickness of the coalbeds in Muli Basin is great, and the burial depth is moderate. The coalbeds are mainly composed of gas coal and coking coal and are in the middle-high metamorphism stage. Gas content in Muli Formation coal is relatively high. The potential of coalbed methane resources is good. The metamorphic degree of coalbeds and the sealing capacity of the top and bottom barriers control the enrichment of coalbed methane. The accumulation models of Jurassic coalbed methane in Muli Basin are mainly gentle syncline and large monoclinic structures. The research of these controlling factors and accumulation models will provide references and basis for further coalbed methane exploration and exploitation in Muli Basin.

Keyword: Muli Basin; Jurassic; coalbed methane; accumulation model

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0 引言

随着我国天然气对外依存度的逐渐攀升, 各类型非常规天然气的勘探开发已刻不容缓。目前我国已探明的煤层气资源丰富, 可作为常规天然气的有利补充^{[1, 2, 3, 4, 5, 6, 7, 8, 9]}。木里盆地位于青海省东部, 煤炭资源丰富, 查明煤炭资源量约42.2亿t, 煤层气资源潜力巨大。盆地呈NWW-SEE向展布, 东西长约190 km, 南北平均宽约40 km, 面积约7 600 km², 包括聚乎更、哆嗦公马、江仓等11个矿区^[10]。但木里盆地煤层气研究仍属空白区, 对煤层气的资源潜力认识不清。因此, 本文通过对木里盆地煤层发育情况、煤体结构、变质程度及含气性等研究, 初步探讨了该区煤层气的富集模式, 为下一步煤层气勘探开发提供了依据。

1 研究区概况

1.1 煤层赋存特征

煤层气资源的丰富程度与煤系地层的分布、煤层埋深及煤层厚度关系密切, 煤层厚度越大且稳定性越好, 就越有利于煤层气藏的形成^{[11, 12]}。木里盆地侏罗系煤层主要赋存于下侏罗统热水组及中侏罗统木里组和江仓组, 其中木里组成煤环境最好, 分布范围较大。

木里盆地自西向东存在3个煤层富集区, 分别为西部的聚乎更地区、中部的江仓地区和东部的热水地区, 各区煤层厚度变化较大。以聚乎更矿区为例(图1), 木里组为主要含煤层段, 含下₁、下₂煤层。下₁煤层厚度为0.34~25.49 m, 平均厚度12.27 m, 含夹矸1~4层, 煤层结构以简单— 较复杂为主; 下₂煤层厚度为1.71~20.94 m, 平均厚度7.91 m, 含夹矸1~3层, 煤层结构一般较简单。赋煤面积约80 km², 埋深400~1 500 m, 由北向南埋深逐渐增加。

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	图1 木里盆地聚乎更矿区地层综合柱状图Fig.1 Comprehensive stratigraphic column of Juhugeng area in Muli Basin

木里盆地整体煤层分布稳定, 连续性好, 厚度较大(图2), 为煤层气的形成提供了丰富的物质基础。同时, 聚乎更矿区内的南向斜似单斜的构造形态及江仓矿区的向斜核部, 为煤层气的生成提供了有利的埋深条件(图3)。

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	图2 木里盆地侏罗系煤层累计厚度Fig.2 Cumulative thickness contour of Jurassic coal seams in Muli Basin

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	图3 木里盆地侏罗系煤层顶板埋深Fig.3 Depth contour of Jurassic coalbed top barrier in Muli Basin

1.2 煤体结构和煤层割理

煤体结构和煤层割理对煤层气聚集、运移及压裂有重要影响^{[13, 14]}。木里盆地聚乎更矿区木里组下₁、下₂煤层的煤体结构多为原生结构, 以亮煤— 半亮煤为主, 夹有少量镜煤条带(图4)。木里盆地煤层割理较发育, 聚乎更矿区木里组下₁煤层割理平均密度为11条/5 cm, 下₂煤层割理平均密度为17条/5 cm, 割理延伸距离较长。从割理几何形态看, 以发育孤立网状组合为主, 发育面割理和端割理, 有利于增加煤中裂隙, 改善煤层渗透性。

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	图4 木里盆地聚乎更矿区下₂煤标本Fig.4 Lower 2 coal samples in Juhugeng area of Muli Basin

1.3 变质程度

判断煤层的变质程度一般选取镜质体反射率(R_o)作为评价手段。聚乎更矿区木里组下₁煤层的R_o为0.66%~2.26%, 均值为1.04%, 下₂煤层的R_o为0.65%~2.19%, 均值为1.05%, 以Ⅲ 变质阶段为主。据此判断聚乎更矿区木里组下₁煤层以弱黏煤、气煤和焦煤为主, 下₂煤层以弱黏煤、黏煤、气煤和焦煤为主。聚乎更矿区木里组下₁、下₂煤层的壳质组含量占有机组分比例均较小, 表明煤的变质程度均已达到中、高煤化阶段(表1)。

表1 聚乎更矿区主要目标煤层变质程度 Tab.1 Metamorphic degree of the main target coal seams in Juhugeng area

1.4 含气性

木里盆地侏罗系煤层属于气煤— 瘦煤阶, 对于该阶煤的煤层气资源含气量下限是4.0 m³/t。聚乎更矿区7-4号钻孔下₁煤层含气量最高值为12.13 m³/t, 最低值为1.03 m³/t, 平均值为6.57 m³/t; 下₂煤层含气量最高值为11.72 m³/t, 最低值为5.08 m³/t, 平均值为7.83 m³/t。

煤炭钻孔现场解吸结果显示, 聚乎更矿区下₁煤层含气量变化为0.22~5.52 m³/t, 下₂煤层含气量变化为0.12~11.14 m³/t(表2), 江仓矿区木里组含气量变化为0.03~2.82 m³/t。整个木里盆地煤层气含量不同地区差异较大, 聚乎更、江仓、外力哈达、热水矿区的煤层气含量远高于默勒和海德尔矿区。

表2 聚乎更矿区钻孔煤层含气量(空气干燥基)和成分 Tab.2 Gas content (air dried basis) and composition of drilled coal seams in Juhugeng area

1.5 物性及吸附性

煤的孔隙度主要与煤的变质程度有关, 总体来看, 随煤阶升高, 孔隙度逐渐降低, 到焦煤后就不再增加^[15]。之后, 随煤阶升高, 孔隙度又开始有所回升。木里盆地煤变质程度处于长焰煤到焦煤阶段, 煤储层孔隙度普遍较高, 介于2.7%~13.7%之间。木里盆地聚乎更矿区、江仓矿区、热水矿区及默勒矿区的煤储层渗透率变化较大, 范围为(0.03~10.6)× 10^-3μ m², 利于煤层气的储集和运移, 而且对煤层气的开采也较有利。木里盆地煤储层渗透率并非与孔隙度完全呈正相关关系, 受构造影响, 煤体结构破坏严重, 连通性变差, 造成渗透率普遍较低。

煤层中的甲烷主要以吸附在煤体内表面上的吸附气为主构成, 在一定储层压力条件下, 煤的吸附能力决定煤层单位含气量的高低^[16]。木里盆地聚乎更矿区、江仓矿区、热水矿区及默勒矿区等煤储层11个样品平衡水兰氏体积介于17.25~24.04 m³/t之间, 平均为20.94 m³/t, 干燥无灰基兰氏体积介于18.94~26.64 m³/t之间, 平均为23.10 m³/t, 表明木里盆地具有较强的储气能力。兰氏压力中等— 较高, 变化范围为1.99~13.33 MPa, 表明木里盆地煤层气产能较高。

2 煤层气主控因素

2.1 生气条件

不同的煤岩组分生烃能力不同: 壳质组生烃能力最强, 其次为镜质组, 惰质组最差^[17]。木里盆地煤的镜质组含量普遍较高, 平均为60%~80%, 镜质组的生气能力相对较好, 对煤层气生成的贡献较大, 由此为盆地煤层气的生成奠定了良好的物质基础。

煤阶是衡量煤化作用程度或煤变质程度的参数, 常用煤的镜质体反射率指标来划分煤阶^[18]。从煤层气成烃机理上来讲, 镜质体反射率越高, 煤的变质程度也愈高。煤阶直接影响煤的生气多少及煤储层孔隙、裂隙发育和吸附特性等, 所以煤阶对煤层气藏的形成起重要作用。

整体来看, 木里盆地变质程度较低, 还未达到大规模生气阶段。盆地东部默勒、海德尔等地区主采煤层多数变质程度很低, 不利于煤层气的大量生成, 而盆地中西部地区的煤变质程度相对较高, 生气条件较好。

2.2 保存条件

煤层顶、底板即围岩的物性特征包括围岩的孔隙性、渗透性和节理发育程度等, 这些直接决定着盖层突破压力这一重要物性, 从而影响围岩对煤储层的封盖性能, 决定煤层气的保存和逸散条件^[19]。

木里盆地地区煤层顶、底板岩性以泥岩、粉砂岩为主, 整体条件较好。以聚乎更矿区为例, 煤层的顶板一般以泥岩、粉砂岩为主, 局部为砂质泥岩和细砂岩, 厚度不大, 多数在1~10 m之间, 渗透率较低, 形成了矿区的区域性盖层(图5)。整体来看, 盆地西部聚乎更、江仓、哆嗦公马矿区的顶、底板岩性以泥岩、粉砂岩为主, 封盖能力较强。盆地东部海德尔、默勒矿区的顶、底板岩性也以泥岩、粉砂岩为主, 整体封盖能力较好。而外力哈达、柴达尔井田的顶、底板虽以细粒岩性为主, 但受后期构造影响, 节理、裂隙发育, 封盖能力较弱。木里盆地聚乎更、江仓、海德尔和默勒矿区煤层顶、底板封盖性较好, 对煤层气的富集和保存较有利。

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	图5 聚乎更矿区下₁煤层顶板岩性分布Fig.5 Lithofacies distribution of top barrier of Lower 1 coalbed in Juhugeng area

3 煤层气成藏模式

煤层气藏是一种非常规天然气藏, 无论其气藏类型还是成藏机理, 都与常规气藏有着较大差异。其主要特征为: ①煤层气藏是煤层气聚集的基本单元, 具有明显的边界, 与周围地质体分隔; ②独立的流体系统是指经历了相同的演化过程和相似的地质作用下的基本流体单元; ③煤岩体是受顶、底板控制, 连续分布的煤层^{[20, 21, 22]}。通过对木里盆地煤层气富集主控因素及边界条件进行分析, 认为构造特征为本区煤层气富集最主要的因素, 其次为煤系条件和围岩条件。分析认为木里盆地成藏模式有2种: 第1种是受逆冲断层控制的倾角较小的大型单斜构造, 断层封闭性好, 埋深相对较大, 对煤层气的富集与保存极为有利, 如聚乎更矿区的四井田和一井田; 第2种是在江仓矿区发育的大型向斜, 虽然倾角较大, 但是储层压力也较大, 埋深适中, 同样是煤层气发育的有利位置。

3.1 宽缓向斜富集

宽缓向斜煤层气成藏模式主要发育于江仓矿区, 两翼倾角较小, 埋深较大, 煤层的顶、底板主要为泥岩和粉砂岩等, 煤层(煤层组)厚度大, 储层压力大, 有利于煤层气的富集成藏, 因此可作为煤层气勘探的有利目标区(图6)。

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	图6 木里盆地江仓矿区煤层气成藏模式Fig.6 Coalbed methane accumulation model in Muli Basin (Jiangcang area)

木里盆地煤层气富集成藏受煤层的埋深、储层所在构造位置、水文地质条件、煤岩组成、热演化程度等众多因素影响。如图6所示, 向斜构造是煤层气藏形成的有利构造位置。由于向斜两翼煤系地层出露, 煤层气很容易发生逸散, 两翼地区煤层气保存条件比向斜腹部地区差, 从向斜两翼向向斜腹部, 煤储层的上覆岩层厚度不断增大, 使得煤层气在纵向上逸散更加困难, 保存条件变好, 煤层气含量增大。同时, 盆地两翼的煤系露头地区接受降水和地表水(冰雪融水)入渗补给, 当地下水通过补给区和径流区时, 溶解了一部分煤层气, 一定程度上降低了补给区和径流区的煤层气含量。但地下水会携带溶解的煤层气到滞流区, 使滞流区的地下水溶解煤层气不断聚集, 地下水饱和之后煤层气析出, 使滞流区的含气量增高。而且区内的冻土层对于煤层气的保存也起到了一定的积极作用。此外, 水流方向和煤层气的横向逸散方向相反, 阻止了煤层气向上运移, 起到水力封堵作用。向斜的腹部地区, 地下水滞留, 矿化度高, 煤层气的保存条件较好, 有利于煤层气富集成藏。并且向斜腹部的煤层R_o高于向斜两翼, 煤岩的生气量和吸附量均高于盆地两翼。

3.2 大型单斜构造富集

聚乎更矿区内部的南向斜就是逆冲断层控制下的单斜构造, 倾角较小, 单斜层上部的压性封闭断层阻止了煤层气向上运移, 利于煤层气的富集。矿区内的四井田和一井田就是典型的逆冲断层控制下的单斜构造。根据实测的一井田ZK-37孔含气量数据, 下₁煤层的含气量高达5.52 m³/t, 然而此孔的下₁煤层埋深仅有155.8 m, 埋深很浅, 说明封闭性的压性逆冲断层对煤层气的富集起着决定性的影响(图7)。

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	图7 木里盆地聚乎更矿区煤层气成藏模式Fig.7 Coalbed methane accumulation model in Muli Basin (Juhugeng area)

4 结论

(1)木里盆地中— 下侏罗统煤层厚度大, 埋藏适中, 整体处于中— 高变质阶段, 含气量较高, 具有良好的煤层气资源潜力。

(2)煤层的变质程度和顶、底板的封盖能力是木里盆地侏罗系煤层气富集的主控因素, 盆地西部的聚乎更矿区和江仓矿区煤层变质程度高, 顶、底板封盖能力好, 为下一步勘探的有利区域。

(3)木里盆地侏罗系煤层气主要有2种成藏模式, 分别为江仓矿区的宽缓向斜富集模式和聚乎更矿区的大型单斜构造富集模式。

参考文献

文献选项

[1]	康永尚, 姜杉钰, 张兵, 等. 煤层气资源可动用性定性/半定量评价方法研究[J]. 煤炭学报, 2017, 42(11): 2914-2924. [本文引用:1]
[2]	包书景, 李世臻, 徐兴友, 等. 全国油气资源战略选区调查工程进展与成果[J]. 中国地质调查, 2019, 6(2): 1-17. [本文引用:1]
[3]	张家强, 毕彩芹, 李锋, 等. 新能源矿产调查工程进展[J]. 中国地质调查, 2018, 5(4): 1-16. [本文引用:1]
[4]	李登华, 高煖, 刘卓亚, 等. 中美煤层气资源分布特征和开发现状对比及启示[J]. 煤炭科学技术, 2018, 46(1): 252-261. [本文引用:1]
[5]	张道勇, 朱杰, 赵先良, 等. 全国煤层气资源动态评价与可利用性分析[J]. 煤炭学报, 2018, 43(6): 1598-1604. [本文引用:1]
[6]	谢英刚, 孟尚志, 高丽军, 等. 临兴地区深部煤层气及致密砂岩气资源潜力评价[J]. 煤炭科学技术, 2015, 43(2): 21-24, 28. [本文引用:1]
[7]	庚勐, 陈浩, 陈振宏, 等. 我国煤层气富集规律及资源潜力新认识[J]. 天然气地球科学, 2016, 27(9): 1659-1665. [本文引用:1]
[8]	李景明, 巢海燕, 李小军, 等. 中国煤层气资源特点及开发对策[J]. 天然气工业, 2009, 29(4): 9-13. [本文引用:1]
[9]	冯明, 陈力, 徐承科, 等. 中国煤层气资源与可持续发展战略[J]. 资源科学, 2007, 29(3): 100-104. [本文引用:1]
[10]	孟元林, 宋丽环, 周新桂, 等. 木里盆地中侏罗统烃源岩生烃潜力评价[J]. 黑龙江科技大学学报, 2016, 26(2): 157-162. [本文引用:1]
[11]	蔚远江, 杨起, 刘大锰, 等. 我国煤层气储层研究现状及发展趋势[J]. 地质科技情报, 2001, 20(1): 56-60. [本文引用:1]
[12]	张群, 冯三利, 杨锡禄. 试论我国煤层气的基本储层特点及开发策略[J]. 煤炭学报, 2001, 26(3): 230-235. [本文引用:1]
[13]	姜波, 秦勇, 范炳恒, 等. 淮北地区煤储层物性及煤层气勘探前景[J]. 中国矿业大学学报, 2001, 30(5): 433-437. [本文引用:1]
[14]	赵贤正, 杨延辉, 孙粉锦, 等. 沁水盆地南部高阶煤层气成藏规律与勘探开发技术[J]. 石油勘探与开发, 2016, 43(2): 303-309. [本文引用:1]
[15]	秦勇. 国外煤层气成因与储层物性研究进展与分析[J]. 地学前缘, 2005, 12(3): 289-298. [本文引用:1]
[16]	秦勇. 中国煤层气成藏作用研究进展与述评[J]. 高校地质学报, 2012, 18(3): 405-418. [本文引用:1]
[17]	李相方, 蒲云超, 孙长宇, 等. 煤层气与页岩气吸附/解吸的理论再认识[J]. 石油学报, 2014, 35(6): 1113-1129. [本文引用:1]
[18]	李辛子, 王运海, 姜昭琛, 等. 深部煤层气勘探开发进展与研究[J]. 煤炭学报, 2016, 41(1): 24-31. [本文引用:1]
[19]	孙粉锦, 王勃, 李梦溪, 等. 沁水盆地南部煤层气富集高产主控地质因素[J]. 石油学报, 2014, 35(6): 1070-1079. [本文引用:1]
[20]	赵庆波, 孔祥文, 赵奇. 煤层气成藏条件及开采特征[J]. 石油与天然气地质, 2012, 33(4): 552-560. [本文引用:1]
[21]	吴财芳, 秦勇, 傅雪海, 等. 煤层气成藏的宏观动力能条件及其地质演化过程——以山西沁水盆地为例[J]. 地学前缘, 2005, 12(3): 299-308. [本文引用:1]
[22]	李贵红, 张泓. 鄂尔多斯盆地东缘煤层气成藏地质模型[J]. 天然气地球科学, 2015, 26(1): 160-167. [本文引用:1]

2017

0.0

... 目前我国已探明的煤层气资源丰富,可作为常规天然气的有利补充^{[1,2,3,4,5,6,7,8,9]} ...

2019

0.0

... 目前我国已探明的煤层气资源丰富,可作为常规天然气的有利补充^{[1,2,3,4,5,6,7,8,9]} ...

2018

0.0

... 目前我国已探明的煤层气资源丰富,可作为常规天然气的有利补充^{[1,2,3,4,5,6,7,8,9]} ...

2018

0.0

... 目前我国已探明的煤层气资源丰富,可作为常规天然气的有利补充^{[1,2,3,4,5,6,7,8,9]} ...

2018

0.0

... 目前我国已探明的煤层气资源丰富,可作为常规天然气的有利补充^{[1,2,3,4,5,6,7,8,9]} ...

2015

0.0

谢英刚, 孟尚志, 高丽军, 等. 临兴地区深部煤层气及致密砂岩气资源潜力评价[J]. 煤炭科学技术, 2015, 43(2): 21-24, 28.

According to the deep depth of the main seam in Linxing Area at east edge of Ordos,many gas layers features of the sandstone,the paper analyzed the coal reservoir features within the area and evaluated the potential resources of the deep coalbed methane and the compact sandstone gas.The study showed that the structure within the area was simple and mainly was the monoclinic structure.The development of the structure was broken in the some area of the middle east part,the coal reservoir was relative stable and the reservoir pressure was in an under-pressure to normal pressure state and was favorable to the enrichment of the coalbed methane.The deep No.5 and No.9 seams were semi-bright type fat coal to coking coal mainly,the reservoir physical property was quite well and the resources potential of No.9 seam was high and was the main seam for the deep coalbed methane exploration.The layout of compact sandstone was controlled by the sedimentary features of the coal measure strata and was relatively developed in the south part.The study held that the area was favorable to the multi layer simultaneous mining of the deep coal measure coalbed methane and compact sandstone gas and among the area,but the middle and south part could be a favorable zone for a single mining of the coalbed methane.

1.Engineering and Technology Branch,CNOOC Energy Technology and Services Limited,Tianjin300457,China；2.China United Coalbed Methane Corporation Limited,Beijing100011,China

针对鄂尔多斯盆地东缘临兴地区主煤层埋深较深、致密砂岩产气层数较多的特点，分析了区内煤储层特征，评价了深部煤层气及致密砂岩气的资源潜力。研究表明，区内构造简单，以单斜构造为主，东中部局部地区发育断裂，煤储层相对稳定，储层压力呈欠压-常压状态，有利于煤层气的富集；深部5号和9号煤层以半亮型的肥煤到焦煤为主，储层物性较好，且9号煤层资源潜力较大，是深部煤层气勘探的主要煤层；致密砂岩展布主要受控于煤系地层沉积特征，在北部地区相对发育。研究认为，该区有利于深部煤系煤层气与致密砂岩气多层共采，而中南部地区为煤层气单采有利区。

... 目前我国已探明的煤层气资源丰富,可作为常规天然气的有利补充^{[1,2,3,4,5,6,7,8,9]} ...

2016

0.0

庚勐, 陈浩, 陈振宏, 等. 我国煤层气富集规律及资源潜力新认识[J]. 天然气地球科学, 2016, 27(9): 1659-1665.

The enrichment regularity of CBM in different coal rank is described.The characteristics of the medium-high coal rank sedimentary controlled reservoir and hydrodynamic gas control and structural adjustment are investigated.Sufficient gas source supply and good sealing conditions are keys to the enrichment of low-rank coal.With further exploration and development of CBM,more and more detailed resource evaluation parameters and rich and reliable research methods,as well as the accuracy and reliability of the results of the evaluation of resources have been further exactituded.Combined with China’s CBM resources classification and distribution results,this study summarized the coal seam gas resources in our country as a whole “North and South Division,East and South Area”.From east to west,it changes from a relatively rich gas into relatively poor gas zone,and from north to south it changes from pressure type area to gradient force type region.In the middle zone of North China,Ordos Basin is easy to form a high yield zone.

PetroChina Research Institute of Petroleum Exploration and Development-Langfang,Langfang 065007,China

阐述了不同煤阶煤层气富集规律，总结了中高煤阶沉积控藏、水动力控气、断裂控制的特征，并指出是否具有充足的气源补给和良好的封盖条件是低煤阶富集的关键。在煤层气地质资源量计算上虽然仍利用体积法，但随着煤层气勘探开发工作的进一步开展，详实的资源评价参数大大增加了计算结果的准确性，同时丰富可采资源量的研究方法，进一步提高了其结果的可靠性。结合我国煤层气资源分类分布结果，总结了我国煤层气资源整体上“南北分区、东西分带”的特征，即由东向西从相对富气带转变为相对贫气带，由北向南从压力类型区渐变为应力类型区，处于中间地带的华北、鄂尔多斯等盆地容易形成富集高产区。

... 目前我国已探明的煤层气资源丰富,可作为常规天然气的有利补充^{[1,2,3,4,5,6,7,8,9]} ...

2009

0.0

李景明, 巢海燕, 李小军, 等. 中国煤层气资源特点及开发对策[J]. 天然气工业, 2009, 29(4): 9-13.

According to the latest national hydrocarbon resource evaluation, the coalbed methane resource with a burial depth less than 2000 m accounts for 36.8 tcm all over China, among which low rank, medium rank and high rank coalbed methane present 30% respectively. Taking three basins representative of different rank coalbed methane: Qinshui, Ordos, and Junggar as cases of study, this paper discusses on the basic geological conditions, resource abundance, and the situation of exploration and development, and puts forward that commercial recovery of coalbed methane should start from largescale coalbearing basins especially those blocks with relatively stable geological structure. The favorable target zone for the high rank coalbed methane development will be artesian flow area, occluded water area and relatively structural high of ramp region; the deploy for the medium rank coalbed methane with good generationreservoir conditions will try to avoid methane oxidation belt and fault belts; and the target zone for the low rank coalbed methane should be on the blocks with different gases as source and relatively stable geological structure.

1. PetroChina Coalbed Methane Co., Ltd., Beijing 100013, China; 2. Langfang Branch, PetroChina Research Institute of Petroleum Exploration & Development, Langfang 065007, China

据新一轮全国油气资源评价结果，我国埋深在2 000 m以浅的煤层气资源量为36.8×1012 m3，煤层气资源十分丰富，其中赋存在低、中、高煤阶中的煤层气资源各占30%左右。分别以国内高、中、低煤阶代表性的盆地——沁水、鄂尔多斯和准噶尔3个盆地为对象，通过研究其基本地质条件、资源丰度及勘探开发状况，认为煤层气资源规模开发要立足大型含煤盆地和构造相对稳定的含煤盆地展开。高煤阶煤层开发应以斜坡带的承压水区、滞留水区及相对构造高部位为目标区；中煤阶煤层生、储条件好，部署应避开甲烷风化带和断层带；低煤阶煤层开发应考虑具多种气源条件和构造相对稳定的区块。

... 目前我国已探明的煤层气资源丰富,可作为常规天然气的有利补充^{[1,2,3,4,5,6,7,8,9]} ...

2007

0.0

冯明, 陈力, 徐承科, 等. 中国煤层气资源与可持续发展战略[J]. 资源科学, 2007, 29(3): 100-104.

China is a country with both huge coal production and abundant resources of coal-bed methane. According to statistics data, the amount of coal-bed methane resources reserves in China is 15.9×10 12 m 3 . The exploitable amount of reserves is 2.0×10 12 m 3 , ranking third place in the world. Although we have recognized the importance of developing coal-bed methane, but its utilization ratio is low still. The coal-bed methane of draining off to the air is about 360×10 8 m 3 annually, with a recycle ratio of 1.56 percent. Coal-bed methane resources quantity in China is the same as in America, but coal-bed methane output in China is 1.6 percent of that in American. Compared with developed countries, a great gap on coal-bed methane development and exploitation in China are still existed. Extracting the methane before exploiting coal could avoid the risk of gas explosion. Coal-bed methane resources as a clean source of nergy, it can change the unreasonable energy structure, reduce the air pollution, protect human health and environment. In the view of sustainable development in the 21st century, we should enhance geological tectonic research on coal basins, build the coal-bed methane mining mode, reinforce international cooperation and enlarge the range of coal-bed methane exploitation.

中国既是煤炭生产消费大国，又是煤层气资源丰富的国家。据统计，我国煤层气资源储量和开采储量分别为15.9×10 12 m 3 ，居世界第三位，煤层气的开发利用潜力十分巨大。开发利用煤层气有益，随意排放则十分有害。虽然我们已认识到开发煤层气的重要性，但我国煤层气利用率仍很低，每年有360×10 8 m 3 的煤层气排放到大气中，回收利用率仅为1.56%；中国和美国煤层气资源量相当，但是，我国煤层气产量仅为美国同期产量的1.6%，我国煤层气在勘探、开发和商业化经营方面，与世界发达国家相比还有一定差距。如何充分利用我国巨大的煤层气资源，从根本上解决能源短缺问题，是新时期摆在我们面前的一个新课题。作者认为煤层气资源作为清洁环保的新型能源，合理的开发利用，可以改变不合理的能源结构，减少大气污染，保护人类健康和赖以生存的环境；先开采煤层气，后开采煤炭，可以从根本上避免煤矿瓦斯爆炸。从21世纪可持续发展观点出发，借助“西气东输”的契机，应加强对含煤盆地地质构造的研究，建立适合中国煤层气开发模式，继续加强国际间合作，扩大煤层气勘探范围，加大煤层气的科技投入，使煤层气资源为我国的现代化建设发挥更大的作用。

... 目前我国已探明的煤层气资源丰富,可作为常规天然气的有利补充^{[1,2,3,4,5,6,7,8,9]} ...

2016

0.0

... 盆地呈NWW-SEE向展布,东西长约190 km,南北平均宽约40 km,面积约7 600 km²,包括聚乎更、哆嗦公马、江仓等11个矿区^[10] ...

2001

0.0

... 1 煤层赋存特征煤层气资源的丰富程度与煤系地层的分布、煤层埋深及煤层厚度关系密切,煤层厚度越大且稳定性越好,就越有利于煤层气藏的形成^[11,12] ...

2001

0.0

2001

0.0

... 2 煤体结构和煤层割理煤体结构和煤层割理对煤层气聚集、运移及压裂有重要影响^[13,14] ...

2016

0.0

... 2 煤体结构和煤层割理煤体结构和煤层割理对煤层气聚集、运移及压裂有重要影响^[13,14] ...

2005

0.0

... 5 物性及吸附性煤的孔隙度主要与煤的变质程度有关,总体来看,随煤阶升高,孔隙度逐渐降低,到焦煤后就不再增加^[15] ...

2012

0.0

... 煤层中的甲烷主要以吸附在煤体内表面上的吸附气为主构成,在一定储层压力条件下,煤的吸附能力决定煤层单位含气量的高低^[16] ...

2014

0.0

... 1 生气条件不同的煤岩组分生烃能力不同: 壳质组生烃能力最强,其次为镜质组,惰质组最差^[17] ...

2016

0.0

... 煤阶是衡量煤化作用程度或煤变质程度的参数,常用煤的镜质体反射率指标来划分煤阶^[18] ...

2014

0.0

... 2 保存条件煤层顶、底板即围岩的物性特征包括围岩的孔隙性、渗透性和节理发育程度等,这些直接决定着盖层突破压力这一重要物性,从而影响围岩对煤储层的封盖性能,决定煤层气的保存和逸散条件^[19] ...

2012

0.0

赵庆波, 孔祥文, 赵奇. 煤层气成藏条件及开采特征[J]. 石油与天然气地质, 2012, 33(4): 552-560.

Based on the occurrence status of coalbed methane and structure setting of coal beds,the accumulation models of coalbed methane are divided into three types:self-source and self-reservoir adsorbed gas,self-source and self-reservoir free gas,and inside-source outside-reservoir gas.Coalbed methane enrichment and production mechanisms vary with various accumulation models.According to methane content and δ 13 C 1 distribution in different coalbed methane accumulation in Qinshui Basin,eastern margin of Ordos Basin,Fuxin Basin and Tiefa Basin,three coalbed methane accumulation stages are indicated as early accumulation stage,late structural-reworking accumulation stage and secondary accumulation stage during production.The secondary accumulation is induced by inter-zone and inner-zone flow during production.Micro-cycles within thick coal beds are analyzed based on sedimentary facies and the coal bed intervals with high coalbed methane content are identified.Furthermore,the types of coal-forming parent materials and their control on coalbed methane enrichment and productivity are studied based on analysis of sedimentary facies.This paper also discusses tectonic stress field and hydrodynamic force influencing coalbed methane accumulation.Finally,this paper summarizes the production characteristics of coalbed methane.The production of methane well can be divided into three stages including blocked,unblocked,and unsaturated stages.The unsaturated stage is subdivided into several step-like declining stages.Structural positions and inner-layer heterogeneity result in three types of self-supporting,exporting and importing production characteristics.

1. Langfang Branch Department, PetroChina Research Institute of Petroleum Exploration and Development, Langfang, Hebei 065007, China; 2. PetroChina Research Institute of Petroleum Exploration and Development, Beijing 100083, China; 3. China University of Geosciences, Beijing 100083, China

根据煤层气的存储状态及煤层所处的构造位置,将煤层气划分为自生自储吸附型、自生自储游离型和内生外储型3种成藏模式,不同成藏模式的富集高产机制不同。基于沁水盆地、鄂尔多斯盆地东缘、阜新及铁法盆地不同层位煤层气甲烷含量及甲烷碳同位素分布研究,煤层气成藏期可划分为早期成藏、后期构造改造成藏和开采中二次成藏3个时期,特别指出了开采中窜位和窜层引发二次成藏的条件。利用沉积相分析厚煤层的层内微旋回,细划分出优质煤层富含气段;进一步利用沉积相探索成煤母质类型及其对煤层气高产富集的控制作用,阐述了构造应力场及水动力对煤层气成藏的作用机理。最后,总结了煤层气的开采特征,指出煤层气井开采中包含阻碍、畅通和欠饱和3个开采阶段,欠饱和阶段可划分为多个阶梯状递减阶段;并认为由构造部位和层内非均质性的差异形成了自给型、外输型和输入型3类开采特征。

... ③煤岩体是受顶、底板控制,连续分布的煤层^[20,21,22] ...

2005

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... ③煤岩体是受顶、底板控制,连续分布的煤层^[20,21,22] ...

2015

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李贵红, 张泓. 鄂尔多斯盆地东缘煤层气成藏地质模型[J]. 天然气地球科学, 2015, 26(1): 160-167.

With over 20 year history,although the CBM development succeeded in some areas in the eastern Ordos Basin,such as Baode,Liulin,etc.,the overall industrialization isn′t balanced.Besides the engineering factors,the divergence of the CBM geology still exists and the building of CBM reservoir model will help to select favorable areas.The Upper Paleozoic CBM reservoir geological model in the eastern Ordos Basin is established.By analyzing the tectonic dynamic condition,sequence stratigraphy,ground water dynamics condition and gas origin,three geological models of CBM reservoir-formation in the eastern Ordos Basin are constructed,including the monocline and low coal rank model,raised arch of the basements and medium coal rank model,and thrust and high coal rank model.The typical areas are Fugu,Wubao-Liulin and Hancheng.The relatively sweet block lies near the stagnant area of the ground water in the monocline and low coal rank model,the tensile nose-shaped uplifted zone in the raised arch of the basements and medium coal rank model,and the compressed tectonic regime in the thrust and high coal rank model.There is good matching to the key elements of CBM reservoir-formation dynamic system in the Wubao-Liulin,which is proposed as the preferred developmental areas in the eastern Ordos Basin,with the best gas storage capacity and permeability|in the monocline and low coal rank model in the Fugu,although the permeability is high,the gas content is low|in the thrust and high coal rank model in Hancheng,the preservation condition is excellent,however,influenced by the thrust belts,the coal structure is destroyed strongly,and the gas recovery declines.

（Xi′an Research Institute of China Coal Technology & Engineering Group Corp.,Xi′an 710054,China）

鄂尔多斯盆地东缘煤层气勘探开发有20余年历史，近年来在保德、柳林等区块规模化开发迅速发展，但总体上全区产业化发展并不均衡。除工程因素外，对煤层气地质条件的认识仍然存在分歧，煤层气成藏地质模型可以为勘探选区提供借鉴。通过对鄂尔多斯盆地东缘构造格架、地层层序、水动力条件及气体成因的研究，构建了研究区北段单斜式低煤级煤层气成藏地质模型、中段基底上拱式中煤级煤层气成藏地质模型、南段边缘推覆式高煤级煤层气成藏地质模型，典型代表区域分别在府谷、吴堡—柳林和韩城。其中，单斜式低煤级煤层气成藏地质模型中，煤层气相对富集于地下水滞留区上部|在基底上拱式中煤级煤层气成藏地质模型中，煤层气高渗富集区位于拉张型鼻状隆起带|在边缘推覆式高煤级煤层气成藏地质模型中，气体富集于挤压型构造转折端。研究结果表明:吴堡—柳林基底上拱式中煤级煤层气成藏地质模型各成藏要素匹配良好，气体储集和渗流条件最好，建议作为优先开发区域|府谷单斜式低煤级的含气性相对差，渗透率高|韩城地区尽管气体保存条件好，但边浅部受边缘逆冲推覆构造的影响，煤体结构破坏严重，煤层气可采性差。

... ③煤岩体是受顶、底板控制,连续分布的煤层^[20,21,22] ...