断陷盆地深层煤岩储层特征、发育主控因素及其勘探领域——以海拉尔盆地呼和湖凹陷白垩系南屯组二段为例

Characteristics, controlling factors of development and exploration areas of deep coal-rock reservoirs in rift basins: a case study of the second member of Cretaceous Nantun Formation in Huhehu Sag, Hailar Basin

高庚 谢颖逸 侯蓓蓓 马文娟 徐慧 王玉杰 霍迎冬 张景远 刘世超 赵威 梁源

GAO Geng XIE Yingyi HOU Beibei MA Wenjuan XU Hui WANG Yujie HUO Yingdong ZHANG Jingyuan LIU Shichao ZHAO Wei LIANG Yuan

1. 中国石油 大庆油田有限责任公司 勘探开发研究院, 黑龙江 大庆 163712; 2. 常州大学 石油与天然气工程学院, 江苏 常州 213164

1. Research Institute of Exploration and Development, PetroChina Daqing Oilfield Company, Daqing, Heilongjiang 163712, China; 2. School of Petroleum and Natural Gas Engineering, Changzhou University, Changzhou, Jiangsu 213164, China

近年来，深层煤岩气勘探不断取得重大突破，揭示了深层煤岩气良好的勘探前景，已成为继致密油气、页岩油气之后的非常规油气勘探开发新热点。海拉尔盆地呼和湖凹陷白垩系南屯组二段(简称南二段)深层煤岩叠置发育、厚度大，深层煤岩气资源潜力大，是重要的勘探接替领域。明确深层煤岩储集层特征、主控因素及发育规律，能够进一步指导东北富煤断陷盆地深层煤岩气勘探与开发。基于呼和湖凹陷的钻井、地震资料，通过岩心、薄片观察与实验分析数据，对南二段深层煤岩优质储集层特征及发育主控因素进行了研究。呼和湖凹陷南二段煤岩储集层具有低灰分、特低水分、中高挥发分的特点，储集空间以有机孔、裂缝和无机矿物质孔为主，孔隙度主要分布在4.5%~7.6%之间，平均为6.0%，渗透率平均为0.45×10-3 μｍ2，孔隙结构以微孔为主，宏孔占比高，更易于游离气赋存。沼泽化滨浅湖广泛分布，控制煤岩大面积发育，为深层煤岩气成藏提供物质来源及储集空间。优质煤岩储集层主要发育于沼泽化滨浅湖广泛分布的洼槽带和陡坡带，形成的煤岩主要为光亮—半亮型原生结构煤，割理、有机孔、微裂缝发育，有机孔沟通微裂缝，孔隙连通率高，物性更佳，含气性更优，更富“游离气”，南部洼槽区和陡坡区更易于形成多种有利源储配置关系，成藏条件优越，预测资源量超万亿立方米，是呼和湖断陷深层煤岩气勘探的有利突破区，有望成为海拉尔盆地第一个万亿立方米深层煤岩气田的突破地。

In recent years, major breakthroughs have been made in deep coal-rock gas exploration, revealing the promising exploration prospects of such resources. This has become a new hotspot in unconventional oil and gas exploration and development, following tight oil and gas and shale oil and gas. The second member of Cretaceous Nantun Formation (N2) in the Huhehu Sag of Hailar Basin is characterized by deep coal-rock layers in a thick stack with high resource potential for deep coal-rock gas. This region is an important area for exploration succession. Clarifying the characteristics, main controlling factors, and development patterns of deep coal-rock reservoirs is essential for the exploration and development of deep coal-rock gas in the coal-bearing rift basins of northeastern China. Based on drilling and seismic data from the Huhehu Sag, the characteristics and main controlling factors of the high-quality coal rock reservoirs in N2 are studied through core and thin section observations and experimental analysis. The coal-rock reservoirs in N2 of the Huhehu Sag have the characteristics of low ash content, ultra-low moisture content, and medium to high volatile matter. The main reservoir space is mainly composed of organic pores, fractures, and inorganic mineral pores, with porosity mainly distributed between 4.5% to 7.6%, with an average of 6.0%. The average permeability is 0.45×10-3 μm2, and the pore structure is mainly microporous, with a high proportion of macropores, making it easier for free gas storage. Swampy shore-shallow lakes are widely distributed, controlling the large-scale development of coal rocks, providing material sources and storage space for deep coal-rock gas reservoir formation. High-quality coal-rock reservoirs are mainly developed in the depression zones and steep slope zones, where swampy shore and shallow lakes are widely distributed. The coal-rocks formed in these areas are mainly bright to semi-bright primary structural coal, forming cleats, organic pores, and micro-fractures. Organic pores are connected to micro-fractures, resulting in high pore connectivity, better physical properties, superior gas content, and richer “free gas”. The southern depression zones and steep slope zones are more likely to form multiple favorable source and reservoir configurations, with superior reservoir formation conditions. The predicted resource volume exceeds one trillion cubic meters, making it a favorable breakthrough area for deep coal-rock gas exploration in the Huhehu Sag. It is expected to become the first trillion-cubic-meter deep coal-rock gas field in the Hailar Basin.

国家科技重大专项(2016ZX0504)、中国石油重大科技专项项目(2017E-14和2019E-25)和中国石油大庆油田有限责任公司科研项目(202121KT002)共同资助。

https://doi.org/10.11781/sysydz2025010089