官田坝向斜煤层气资源及赋存影响因素分析

Analysis on Coalbed Gas Resources in Guantianba Syncline Exploration Area and Factors Influencing Occurrence

根据大量煤田地质勘查资料,采用体积法估算官田坝向斜勘查区煤层气资源量,并对区内煤层气赋存影响因素进行分析。结果表明:该区煤层气资源量丰富,预测资源量1 200 m以浅为107.91×10~8 m^3,具有较好的开采价值。影响研究区煤层气赋存的主要因素为地质构造、煤层埋深、煤层厚度、围岩圈闭能力及水文地质条件。其中煤层埋深起主导作用,煤层埋深与煤层气含量呈正相关关系;其次是地质构造,表现为向斜与断裂控气的特征,向斜两翼煤层气含量低,轴部高,北部较南部高。

According to geological survey data of many coal fields, the paper estimates the coalbed gas resources quantity in Guantianba syncline exploration area with the volumetric approach and analyzes the factors influencing the occurrence of coalbed gas in the area. Results show that the area is rich in coalbed gas resources and the resource quantity at 1200 m or shallower is predicted as 107.91×10~8 m^3, indicating good exploration value. Main factors influencing the occurrence of coalbed gas in survey area are geological structure, depth of coal bed, thickness of coal bed, surrounding rock entrapment ability and hydrogeological conditions.Among them, the depth of coal bed plays a leading role and the depth of coal bed is in positive correlation with the content of coalbed gas. The geological structure plays the secondary role, which is manifested through the characteristics of gas control of syncline and fracture. For the syncline, the content of coalbed gas is low at two wings and high at shaft position, and the content of coalbed gas in the north is higher than that in the south.