沁水盆地郑庄—樊庄区块煤系储层共生成藏微观输导体系  

Study on the micro-transportation system for symbiotic accumulation in coal seam in Zhengzhuang-Fanzhuang block of Qinshui Basin

作　　者：赵慧[1] 杨海星 赵承锦[1] 吴玉琛[1] 朱传真 林玉祥[1] 

机构地区：[1]山东科技大学地质科学与工程学院,山东青岛266590 [2]中国石油煤层气有限责任公司韩城分公司,陕西韩城715409

出　　处：《油气地质与采收率》2016年第4期46-52,共7页Petroleum Geology and Recovery Efficiency

基　　金：国家自然科学基金项目"沁水盆地煤层气与致密砂岩气共生成藏机理研究"(41172108);国家科技重大专项"中深层煤系地层立体勘探有利目标优选"(2016ZX05041005)和"岩性地层油气藏区带;圈闭评价方法与关键技术"(2016ZX05001003)

摘　　要：基于沁水盆地郑庄—樊庄区块煤层气藏与顶板致密砂岩气藏之间存在共生性与不对称性迁移的现象,提出了共生成藏微观输导体系的概念。以煤系储层微观输导体系为研究对象,采用高压压汞实验、低温液氮吸附测试和核磁共振分析等方法,对静态微观输导体系的特征和动态输导机制研究后发现,研究区煤岩静态微观输导体系由过渡孔—微孔为主导的孔隙型输导要素与高密度、高角度的裂隙型输导要素构成;构造抬升引起的降压是煤层气微观输导的动力。古近纪末期至现今,由于构造抬升引起压力变化使得煤岩吸附气解吸,每吨煤解析出14.29 m^3的甲烷。古近纪末期(距今约30 Ma),甲烷分子在煤岩孔径范围内发生Fick型扩散;现今在孔径为5~15 nm的煤岩中发生过渡型扩散,在孔径为15~100 nm的煤岩内发生Fick型扩散。Based on the coexistence and asymmetric migration of coal bed methane(CBM)and coal roof tight sandstone(CRTS)gas of the southern area of Zhengzhuang-Fanzhuang block in Qinshui Basin,the concept of micro-transportation system was proposed for the process of symbiotic gas accumulation. The micro-transportation system was studied by using methods of the high pressure mercury injection,low-temperature liquid nitrogen adsorption and nuclear magnetic resonance(NMR). After studying on the static characteristics and dynamic mechanism of micro-transportation system,it is found that the static micro-transportation system of the coal seam in the study area is mainly consist of transitional pores-micropores and high density and high angle fractures. The decreasing of pressure caused by tectonic uplift is the driving force for the coal seam gas micro-transportation. From the late Paleogene to now,changes in pressure caused by tectonic uplift result in the desorption of gas once adsorbed on coal and 14.29 m^3 methane gas desorbed from one ton coal. Late in Paleogene(30 Ma),methane diffused according to Fick's law within the scope of the coal rock aperture. Today methane diffuses transitionally in coal rock with the aperture of 5-15 nm,and diffuses according to Fick's law in coal rock with the aperture of15-100 nm.

关 键 词：共生成藏微观输导体系 构造抬升输导动力气体 扩散模式动态输导机制 

分 类 号：TE111.1[石油与天然气工程—油气勘探]