煤系地层游离气成藏机制与模式研究
|
摘要
沁水盆地煤系地层游离气资源丰富,主要赋存在煤层顶底板和煤系地层常规储层中。开展游离气成藏机制与模式研究,对本区游离气勘探具有重要意义。
本文研究了沁水盆地演化过程,划分出4个演化阶段,其中燕山期为主要的游离气成藏期；明确了五套主要的生、储、盖组合,其中最主要的生储盖组合为山西组自生自储组合和太原组自生自储组合。
通过游离气成藏要素和成藏主控因素分析,总结了游离气的分布规律：(1)构造高部位有利于游离气的聚集；(2)煤层含气量越高,顶底板储层含气量也越高；(3)煤层顶板及上覆盖层的封闭性决定了游离气聚集的层位,优质盖层之下的储层易于成藏。
本文提出了天然气“多源多相、动态转化、定向聚散”的成藏机理。本区天然气来源于煤岩、暗色泥岩、暗色碳酸盐岩等多种类型母岩,赋存状态多样,谓之“多源多相”；在印支期以来的多期构造运动中,不同赋存状态的天然气既有自己独特的演化历程,其间也存在相互交换,即“动态转化”；而“定向聚散”则强调了本区煤系地层天然气成藏过程的不可逆性。
按游离气藏成藏过程及其后生演化建立了本区游离气成藏模式,将沁水盆地游离气藏分为原生型、调整型和改造型等3种,其中改造型又可进一步划分为原生改造型和调整改造型2种。
采用煤层含气量+储层物性+盖层封闭性的思路进行游离气远景评价,得出盆地中央带为有利区(Ⅰ区)、盆地边部为较有利区(Ⅱ区)。
Coal strata in Qinshui Basin are rich in natural gas resources, and free gas mainly exists in the roof and floor of coal-bed and in the conventional reservoirs of coal seam formation in the. The study of free gas accumulation mechanism and accumulation model has great meaning in exploring free gas in Qinshui Basin.
This paper make a definite concept of four process stages of the revolution of the coal strata in Qinshui Basin by comprehensive study which including Yanshanian-major natural gas accumulation stages of development. In Yanshanian, there are five sets of main source-reservoir-cap assemblage, and the self-generating and self-preserving reservoirs of Shanxi formation and Taiyuan formation are tow main sets.
Through the analysis of the accumulation elements and the main controlling factors of free gas, the paper summarizes the rule of the distribution of free gas:(1) structures of high position are favorable to the accumulation of free gas; (2) the coal bed methane content of the roof and floor of coal seam is higher as the gas content of the coal seam is higher; (3) the closeness of the roof of coal seam and covering layer decides the horizon of the gathering of free gas, the good sealing condition is good for accumulation.
The conclusion is the accumulation mechanism, including multi-source and multi-phase state, dynamic transformation, unidirectionally accumulate and escape. Natural gas of coal measure strata in this area comes from many kinds of source rocks, such as coal, dark mudstone and dark carbonate rock, and exists in many states. So we call that“multi-source and multi-phase state”. Since Indo-Chinese period, different phasestates of natural gas have different processes of transformation, and they're interconvertible. That is so-called“dynamic transformation”, while the "unidirectionally accumulate and escape" emphasizes the irreversibility of the process of accumulation.
In this paper, I set up the accumulation model according to the accumulation process and secondary evolution of free gas, and free gas reservoir of Qinshui Basin could be classified into three types:native, adjustment and transformation. And the adjusted gas reservoir could be further divided into native-transformation type and adjusted-transformation type.
By evaluating free gas prospect synthetically based on the overall consideration of the content of coal seam gas, properties of reservoir and closeness of seal, the most favorable gas-bearing zones located in the central belt of the basin (I zone) and the relatively favorable gas-bearing zones located in the edge of the basin (II zone) are recognized.
本文研究了沁水盆地演化过程,划分出4个演化阶段,其中燕山期为主要的游离气成藏期；明确了五套主要的生、储、盖组合,其中最主要的生储盖组合为山西组自生自储组合和太原组自生自储组合。
通过游离气成藏要素和成藏主控因素分析,总结了游离气的分布规律：(1)构造高部位有利于游离气的聚集；(2)煤层含气量越高,顶底板储层含气量也越高；(3)煤层顶板及上覆盖层的封闭性决定了游离气聚集的层位,优质盖层之下的储层易于成藏。
本文提出了天然气“多源多相、动态转化、定向聚散”的成藏机理。本区天然气来源于煤岩、暗色泥岩、暗色碳酸盐岩等多种类型母岩,赋存状态多样,谓之“多源多相”；在印支期以来的多期构造运动中,不同赋存状态的天然气既有自己独特的演化历程,其间也存在相互交换,即“动态转化”；而“定向聚散”则强调了本区煤系地层天然气成藏过程的不可逆性。
按游离气藏成藏过程及其后生演化建立了本区游离气成藏模式,将沁水盆地游离气藏分为原生型、调整型和改造型等3种,其中改造型又可进一步划分为原生改造型和调整改造型2种。
采用煤层含气量+储层物性+盖层封闭性的思路进行游离气远景评价,得出盆地中央带为有利区(Ⅰ区)、盆地边部为较有利区(Ⅱ区)。
Coal strata in Qinshui Basin are rich in natural gas resources, and free gas mainly exists in the roof and floor of coal-bed and in the conventional reservoirs of coal seam formation in the. The study of free gas accumulation mechanism and accumulation model has great meaning in exploring free gas in Qinshui Basin.
This paper make a definite concept of four process stages of the revolution of the coal strata in Qinshui Basin by comprehensive study which including Yanshanian-major natural gas accumulation stages of development. In Yanshanian, there are five sets of main source-reservoir-cap assemblage, and the self-generating and self-preserving reservoirs of Shanxi formation and Taiyuan formation are tow main sets.
Through the analysis of the accumulation elements and the main controlling factors of free gas, the paper summarizes the rule of the distribution of free gas:(1) structures of high position are favorable to the accumulation of free gas; (2) the coal bed methane content of the roof and floor of coal seam is higher as the gas content of the coal seam is higher; (3) the closeness of the roof of coal seam and covering layer decides the horizon of the gathering of free gas, the good sealing condition is good for accumulation.
The conclusion is the accumulation mechanism, including multi-source and multi-phase state, dynamic transformation, unidirectionally accumulate and escape. Natural gas of coal measure strata in this area comes from many kinds of source rocks, such as coal, dark mudstone and dark carbonate rock, and exists in many states. So we call that“multi-source and multi-phase state”. Since Indo-Chinese period, different phasestates of natural gas have different processes of transformation, and they're interconvertible. That is so-called“dynamic transformation”, while the "unidirectionally accumulate and escape" emphasizes the irreversibility of the process of accumulation.
In this paper, I set up the accumulation model according to the accumulation process and secondary evolution of free gas, and free gas reservoir of Qinshui Basin could be classified into three types:native, adjustment and transformation. And the adjusted gas reservoir could be further divided into native-transformation type and adjusted-transformation type.
By evaluating free gas prospect synthetically based on the overall consideration of the content of coal seam gas, properties of reservoir and closeness of seal, the most favorable gas-bearing zones located in the central belt of the basin (I zone) and the relatively favorable gas-bearing zones located in the edge of the basin (II zone) are recognized.
引文
1.郝石生,黄志龙.天然气盖层实验研究及评价[J].沉积学报,1991,9(4)：20-26.
2.郝石生,柳广弟.天然气资源评价的运聚动平衡模型[J].石油勘探与开发,1993,20(3)：16-21.
3.赵贤正.沁水盆地煤层气勘探开发回顾与展望[J].中国煤层气,2010,7(6)：3-4.
4.许振永,王延斌,陈德元,等.沁水盆地晚古生代煤系层序地层及岩相古地理研究[J].煤田地质与勘探.2007,35(4)：5-11.
5.贾建称.沁水盆地晚古生代含煤沉积体系及其控气作用[J].地球科学与环境学报,2007,29(4)：374-382.
6.山西省地质矿产局.山西省区域地质志[M].北京：地质出版社,1989：95-237.
7.陈刚,刘林玉.沁水盆地古生界天然气圈闭条件分析[J].西北地质.1998,19(4)：34-38.
8.邓祖佑,王少昌,姜正龙,等.天然气封盖层的突破压力[J].石油与天然气地质.2000,21(2)：136-138.
9.陈刚.沁水盆地向斜型水封气藏形成条件探讨[J].石油与天然气地质.1998,19(4)：302-306.
10.王红岩,张建博,刘洪林,等.沁水盆地南部煤层气藏水文地质特征[J].煤田地质与勘探,2001,29(5)：33-36.
11.任战利,肖晖.沁水盆地新生代抬升冷却事件的确定[J].石油与天然气地质,2005,26(1)：109-113.
12.秦勇,宋党育.山西南部煤化作用及其古地热系统—兼论煤化作用控气地质机理[M].北京：地质出版社,1998：38-73.
13.陈墨香主编,华北地热[M],北京：科学出版社,1989：79-84.
14.吴中海,吴珍汉.鄂尔多斯、沁水盆地晚新生代隆升—剥蚀历史[J].地质科技情报.2001,20(3)：16-20.
15.任战利,赵重远.鄂尔多斯盆地与沁水盆地中生代晚期地温场对比研究[J].沉积学报.1997,15(2)：134-137.
16.孙占学,张文.沁水盆地大地热流与地温场特征[J].地球物理学报.2006,49(1)：130-134.
17.任战利,赵重远.沁水盆地中生代晚期构造热事件[J].石油与天然气地质.1999,20(1)： 46-48.
18.承金,汪新文.山西沁水盆地热史演化特征[J].现代地质.2009,23(6)：1093-1099.
19.李伟,张枝焕,朱雷,等.山西沁水盆地石炭—二叠系煤层生排烃史分析[J].沉积学报,2005,23(2)：337-344.
20.蒋有录,查明.石油天然气地质与勘探[M].北京：石油工业出版社.2006.
21.戴金星,裴锡古,戚厚发主编.中国天然气地质学(卷一)[M].北京：石油工业出版社,1992：93-286.
22.杨起,韩德馨.中国煤田地质学(上册)[M].北京：煤炭工业出版社,1979：209-248.
23.杨起.中国煤变质作用[M].北京：煤炭工业出版社,1996：184-196.
24.王一兵,孙景民,鲜保安.沁水煤层气田开发可行性研究[J].天然气,2006,2(1)50-53.
25.李五忠,王一兵,田文广,等.沁水盆地南部煤层气可采性评价及有利区块优选[J].天然气,2006,3(5)：62-64.
26.李明宅.沁水盆地煤层气勘探及地质分析[J].天然气工业,2000,20(4)：24-26.
27.宁正伟,陈霞.华北石炭二叠系煤化变质程度与煤层气储集性的关系[J].石油与天然气地质,1996,17(2)：156-159.
28.秦勇,宋党育,王超.山西南部晚古生代煤的煤化作用及其控气特征[J].煤炭学报,1997,22(3)：230-235.
29.刘建国.根据自然电位测井数据确定地层水电阻率的方法[J].新疆石油天然气,2006,2(1)：22-24.
30.接铭训,李明宅.沁水盆地南部煤成气勘探前景[J].勘探家.2000,5(2)：39-42.
31.赵庆波.煤成气地质与勘探技术[M].北京：石油工业出版社,1999.
32.张建博,王红岩.沁水煤成气有利区预测[M].徐州：中国矿业大学出版社,2001.
33.王一兵,赵庆波.沁水盆地环状斜坡带煤层气高产富集条件及有利目标评价[J].天然气工业,1997,17(4)：80-83.
34.白玉宝.山西沁水盆地南缘奥陶—石炭系油气远景评价[J].西安地质学院学报.1995,17(2)：39-43.
35.傅家谟,刘德汉.煤成烃地球化学[M].北京：科学出版社.1990：266-322.
36.聂百胜,张力,马文芳.煤层甲烷在煤孔隙中扩散的微观机理[J].煤田地质与勘探.2000,28(6)：20-22.
37.张慧,王晓刚.煤的显微构造及其储集性能[J].煤田地质与勘探.1998,26(6)：34-37.
38.赵靖舟,时保宏.沁水盆地煤层气富集单元划分[J].科学通报.2005,50(增刊)：126-130.
39. Home J C, Ferm J C,Caruccio F T, et al. Depsitional Models in Coal Exploration and Mine Planning in Appalachian Region[J].AAPG..1978,62(12):2379-2411.
40. Dillon L, Schwedersky G, Guilherme V, et al. A Multiscale DHI Elastic Attributes Evaluation. The leading Edge,2003,22(10):1024-1029.
41. Bradley, J.S. et al. Abnormal Formation Pressure [J]. AAPG Bulletin,1975,59:957-973.
42. Chapman R E. Mechanical Versus Thermal Cause of Abnormally High Pore Pressure in Shale [J]. AAPG Bulletin,1980,64:2079-2083.
43. Hunt J M. Generation and Migration of Petroleum from Abnormally Pressured Fluid Compartments [J]. AAPG Bulletin,1990,74(1):1-12.
44. Green P F, Duddy I R, Gleadow A JW, et al. Thermal annealing of fission tracks in apatite 4. Quantative Modeling Techniques and Extension to Geological Timescales [J]. Chemical Geology,1989,79:155-182.
45. Pashin J C, Groshong Jr R H. Structural Control of Coal bed Methane Production in Alabama [J].International Journal of Coal Geology,1998,38(1):89-113.
46. Cox M H, Groshong R H. Relationship between Fractures and the Structure in Coalbed-mathane Fields of Eastern Black Warrior Basin, Alabama [G]. Annual Meeting ExPanded Abstracts-AAPG,2000:32-33.
47. Dickinson W R, Suczek C A. Plate Tectonics and Sandstone Compositions[J]. Bull. Am. Assoc. Pet. Geol.1979,63:2164-2182.
48. Bustion R M, Clarkson C R. Geological Controls on Coalbed Methane Reservoir Capacity Gas Content [J]. International Journal of Coal Geology,1998,38(1):3-6.
49. Blundell D J. Some Observation on Basin Evolution and Dy-namics [J]. Journal of the Geological Society,1991,148:189-800.
50. Hubbert M K. Entrapment of Petroleum under Hydrodynamic Conditions [J]. AAPG Bulletin,1953,37(8):1954-2026.
51. Scott A R, Kaiser W R, Ayers W B, et al. Thermogenic and Secondary Biogenic Gases, San Juan Basin [J]. AAPG Bulletin.1994,78(8):1186-1209.
2.郝石生,柳广弟.天然气资源评价的运聚动平衡模型[J].石油勘探与开发,1993,20(3)：16-21.
3.赵贤正.沁水盆地煤层气勘探开发回顾与展望[J].中国煤层气,2010,7(6)：3-4.
4.许振永,王延斌,陈德元,等.沁水盆地晚古生代煤系层序地层及岩相古地理研究[J].煤田地质与勘探.2007,35(4)：5-11.
5.贾建称.沁水盆地晚古生代含煤沉积体系及其控气作用[J].地球科学与环境学报,2007,29(4)：374-382.
6.山西省地质矿产局.山西省区域地质志[M].北京：地质出版社,1989：95-237.
7.陈刚,刘林玉.沁水盆地古生界天然气圈闭条件分析[J].西北地质.1998,19(4)：34-38.
8.邓祖佑,王少昌,姜正龙,等.天然气封盖层的突破压力[J].石油与天然气地质.2000,21(2)：136-138.
9.陈刚.沁水盆地向斜型水封气藏形成条件探讨[J].石油与天然气地质.1998,19(4)：302-306.
10.王红岩,张建博,刘洪林,等.沁水盆地南部煤层气藏水文地质特征[J].煤田地质与勘探,2001,29(5)：33-36.
11.任战利,肖晖.沁水盆地新生代抬升冷却事件的确定[J].石油与天然气地质,2005,26(1)：109-113.
12.秦勇,宋党育.山西南部煤化作用及其古地热系统—兼论煤化作用控气地质机理[M].北京：地质出版社,1998：38-73.
13.陈墨香主编,华北地热[M],北京：科学出版社,1989：79-84.
14.吴中海,吴珍汉.鄂尔多斯、沁水盆地晚新生代隆升—剥蚀历史[J].地质科技情报.2001,20(3)：16-20.
15.任战利,赵重远.鄂尔多斯盆地与沁水盆地中生代晚期地温场对比研究[J].沉积学报.1997,15(2)：134-137.
16.孙占学,张文.沁水盆地大地热流与地温场特征[J].地球物理学报.2006,49(1)：130-134.
17.任战利,赵重远.沁水盆地中生代晚期构造热事件[J].石油与天然气地质.1999,20(1)： 46-48.
18.承金,汪新文.山西沁水盆地热史演化特征[J].现代地质.2009,23(6)：1093-1099.
19.李伟,张枝焕,朱雷,等.山西沁水盆地石炭—二叠系煤层生排烃史分析[J].沉积学报,2005,23(2)：337-344.
20.蒋有录,查明.石油天然气地质与勘探[M].北京：石油工业出版社.2006.
21.戴金星,裴锡古,戚厚发主编.中国天然气地质学(卷一)[M].北京：石油工业出版社,1992：93-286.
22.杨起,韩德馨.中国煤田地质学(上册)[M].北京：煤炭工业出版社,1979：209-248.
23.杨起.中国煤变质作用[M].北京：煤炭工业出版社,1996：184-196.
24.王一兵,孙景民,鲜保安.沁水煤层气田开发可行性研究[J].天然气,2006,2(1)50-53.
25.李五忠,王一兵,田文广,等.沁水盆地南部煤层气可采性评价及有利区块优选[J].天然气,2006,3(5)：62-64.
26.李明宅.沁水盆地煤层气勘探及地质分析[J].天然气工业,2000,20(4)：24-26.
27.宁正伟,陈霞.华北石炭二叠系煤化变质程度与煤层气储集性的关系[J].石油与天然气地质,1996,17(2)：156-159.
28.秦勇,宋党育,王超.山西南部晚古生代煤的煤化作用及其控气特征[J].煤炭学报,1997,22(3)：230-235.
29.刘建国.根据自然电位测井数据确定地层水电阻率的方法[J].新疆石油天然气,2006,2(1)：22-24.
30.接铭训,李明宅.沁水盆地南部煤成气勘探前景[J].勘探家.2000,5(2)：39-42.
31.赵庆波.煤成气地质与勘探技术[M].北京：石油工业出版社,1999.
32.张建博,王红岩.沁水煤成气有利区预测[M].徐州：中国矿业大学出版社,2001.
33.王一兵,赵庆波.沁水盆地环状斜坡带煤层气高产富集条件及有利目标评价[J].天然气工业,1997,17(4)：80-83.
34.白玉宝.山西沁水盆地南缘奥陶—石炭系油气远景评价[J].西安地质学院学报.1995,17(2)：39-43.
35.傅家谟,刘德汉.煤成烃地球化学[M].北京：科学出版社.1990：266-322.
36.聂百胜,张力,马文芳.煤层甲烷在煤孔隙中扩散的微观机理[J].煤田地质与勘探.2000,28(6)：20-22.
37.张慧,王晓刚.煤的显微构造及其储集性能[J].煤田地质与勘探.1998,26(6)：34-37.
38.赵靖舟,时保宏.沁水盆地煤层气富集单元划分[J].科学通报.2005,50(增刊)：126-130.
39. Home J C, Ferm J C,Caruccio F T, et al. Depsitional Models in Coal Exploration and Mine Planning in Appalachian Region[J].AAPG..1978,62(12):2379-2411.
40. Dillon L, Schwedersky G, Guilherme V, et al. A Multiscale DHI Elastic Attributes Evaluation. The leading Edge,2003,22(10):1024-1029.
41. Bradley, J.S. et al. Abnormal Formation Pressure [J]. AAPG Bulletin,1975,59:957-973.
42. Chapman R E. Mechanical Versus Thermal Cause of Abnormally High Pore Pressure in Shale [J]. AAPG Bulletin,1980,64:2079-2083.
43. Hunt J M. Generation and Migration of Petroleum from Abnormally Pressured Fluid Compartments [J]. AAPG Bulletin,1990,74(1):1-12.
44. Green P F, Duddy I R, Gleadow A JW, et al. Thermal annealing of fission tracks in apatite 4. Quantative Modeling Techniques and Extension to Geological Timescales [J]. Chemical Geology,1989,79:155-182.
45. Pashin J C, Groshong Jr R H. Structural Control of Coal bed Methane Production in Alabama [J].International Journal of Coal Geology,1998,38(1):89-113.
46. Cox M H, Groshong R H. Relationship between Fractures and the Structure in Coalbed-mathane Fields of Eastern Black Warrior Basin, Alabama [G]. Annual Meeting ExPanded Abstracts-AAPG,2000:32-33.
47. Dickinson W R, Suczek C A. Plate Tectonics and Sandstone Compositions[J]. Bull. Am. Assoc. Pet. Geol.1979,63:2164-2182.
48. Bustion R M, Clarkson C R. Geological Controls on Coalbed Methane Reservoir Capacity Gas Content [J]. International Journal of Coal Geology,1998,38(1):3-6.
49. Blundell D J. Some Observation on Basin Evolution and Dy-namics [J]. Journal of the Geological Society,1991,148:189-800.
50. Hubbert M K. Entrapment of Petroleum under Hydrodynamic Conditions [J]. AAPG Bulletin,1953,37(8):1954-2026.
51. Scott A R, Kaiser W R, Ayers W B, et al. Thermogenic and Secondary Biogenic Gases, San Juan Basin [J]. AAPG Bulletin.1994,78(8):1186-1209.