准东地区低煤阶煤层气成藏条件与有利区预测

发布时间：2018-02-10 16:20

本文关键词： 准噶尔盆地东部煤层气低煤阶成藏模式资源评价有利区优选　出处：《中国地质大学(北京)》2016年博士论文　论文类型：学位论文

【摘要】：准噶尔盆地东部地区主要发育褐煤及长焰煤,蕴含丰富的煤层气资源,为中国低阶煤层气资源重点勘探目标区。但由于该区受多期构造运动控制,煤层发育条件比较复杂,煤层气成藏条件与富集机理认识不清,为下一步煤层气勘探部署增加了难度。本文以准噶尔盆地东部地区侏罗系煤系地层为研究对象,通过开展含煤区基础地质、成煤环境、煤储层发育特征以及控制因素研究,建立了相应的成藏模式;在此基础上,通过相应的数学方法开展煤层气资源计算,并建立煤层气有利区优选评价体系。主要成果及认识如下:(1)准东地区位于克拉美丽山与博格达山之间,在多期构造运动的共同作用下,形成凸凹相间的“棋盘”状构造格局。盆地构造演化及现今构造格局对该区煤层发育以及煤层气富集成藏的控制作用显著。燕山运动以来,准东地区在周缘挤压和压扭应力场作用下持续隆升,较浅的埋深导致煤层煤化作用程度较低,热成因生烃作用严重受限;此外,后期构造抬升作用造成含煤层系盖层剥蚀严重,不利于煤层气富集保存。(2)准东地区中-下侏罗统西山窑组与八道湾组的宏观煤岩类型及煤变质程度均差异较大,且前者煤岩孔隙类型以大孔为主,微小孔基本不发育,后者则以微小孔为主;较大的孔隙直径及相对较浅的埋深导致西山窑组煤孔渗条件优于八道湾组。此外,八道湾组煤岩兰氏体积大于西山窑组,但兰氏压力值却相反。(3)基于准东地区煤层气成藏地质控制作用,并结合相应的煤层气成藏实例分析,建立了三种准东地区煤层气富集成藏模式,分别为南部山前带富集模式、深部凹陷富集模式以及开放斜坡逸散模式。(4)利用体积法计算求得准东地区西山窑组煤层气资源量约为1596.82亿m3,可采资源量1223.43亿m3,地质丰度0.45亿m3/km2,可采丰度0.34亿m3/km2。此外,运用模糊数学层次分析法对煤层气选区关键要素进行定量排序,建立煤层气选区评价标准,优选该区西部地区为下一步煤层气勘探的重点目标区。
[Abstract]:Lignite and long flame coal are mainly developed in the eastern part of Junggar Basin, which contains abundant coal bed methane resources and is the key exploration target area for low rank coal bed methane resources in China. However, because the area is controlled by multi-stage tectonic movement, the development conditions of coal seam are quite complex. The formation conditions and accumulation mechanism of coalbed methane (CBM) are not clear, which makes it more difficult for the next CBM exploration to be deployed. In this paper, the Jurassic coal series strata in the eastern area of Junggar Basin are taken as the research object, and the coal-forming environment is obtained by developing the basic geology of the coal-bearing area. Based on the study of the characteristics of coal reservoir development and the controlling factors, the corresponding reservoir forming model is established, and the calculation of coalbed methane resources is carried out through the corresponding mathematical method. The main achievements and understanding are as follows: (1) the Zhongnong area is located between the Karim Mountain and the Bogda Mountains, and under the joint action of the multi-stage tectonic movement, The tectonic evolution of the basin and the present tectonic framework control the coal seam development and coalbed methane accumulation in this area. Since the Yanshanian movement, Due to the continuous uplift of coal seams under the action of compression and compression and torsional stress field, the coal seam coalification is low and the thermal hydrocarbon generation is severely limited, in addition, the late tectonic uplift results in serious denudation of the coal bed cap. In the middle and lower Jurassic Xishanyao formation and Badaowan formation, the macroscopic coal rock types and the coal metamorphic degree of the middle and lower Jurassic Xishanyao formation and the Badaowan formation are all different, and the porosity types of the former coal rocks are dominated by large pores, and the micropores are basically not developed. The latter is dominated by tiny pores, the larger pore diameter and relatively shallow burying depth result in better pore and permeability conditions in Xishanyao formation than in Badaowan formation. In addition, the coal rock of Badaowan formation is larger than that of Xishanyao formation. On the basis of geological control of coalbed methane accumulation in Zhundong area and the analysis of corresponding coalbed methane reservoir forming examples, three types of coalbed methane rich integrated reservoir models in Zhundong area are established, which are the enrichment models of the southern mountain front belt, respectively. The enrichment model of deep sag and the escape model of open slope. 4) by using volume method, the CBM resources of Xishanyao formation in Zhundong area are estimated to be about one hundred and fifty-nine billion six hundred and eighty-two million m3, recoverable resources one hundred and twenty-two billion three hundred and forty-three million m3, geological abundance 45 million m3 / km2, recoverable abundance 34 million m3 / km2.In addition, it is found that the coalbed methane resources of Xishanyao formation are about one hundred and fifty-nine billion six hundred and eighty-two million m3, one hundred and twenty-two billion three hundred and forty-three million m3, 45 million m3 / km 2, and 34 million m3 / km 2, respectively. By using fuzzy analytic hierarchy process (AHP), the key elements of CBM district are quantitatively sorted, the evaluation standard of CBM selection is established, and the western region of this area is chosen as the next key target area for CBM exploration.
【学位授予单位】：中国地质大学(北京)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P618.13

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