织纳地区龙潭组煤系页岩气储层特征与勘探潜力评价

Evaluation of Shale Gas Reservoir Characteristics and Exploration Potential of Longtan Formation in Zhina Area

为查明织纳地区龙潭组页岩气勘探前景,通过分析Z2井龙潭组泥页岩样品的矿物组成、有机地化特征、微观孔隙特征、钻孔泥页岩厚度、分布情况及其含气性特征,研究龙潭组页岩气储层特征并对页岩气勘探潜力进行评价。结果表明:泥页岩有机质类型为Ⅱ_(2)-Ⅲ型,且以Ⅱ_(2)为主,总有机碳含量为1.34%~8.25%,平均值为3.68%,有机质成熟度为0.92%~3.24%,平均值为2.45%,属于高-过高成熟演化阶段,具有较好的生气潜力。扫描电镜结果显示泥页岩样品主要发育四类微观孔隙,包括粒内孔、粒间孔、有机质孔和微裂隙,内部孔隙发育,为页岩气提供良好的储集空间。Z2井泥页岩脆性矿物含量为24.40%~63.08%,平均值为41.22%,泥页岩总厚度为170.74 m,占比42%,发育5个有效连续厚度大于15 m的泥页岩层,与邻井可形成2个泥页岩层段,适宜进行压裂改造。织纳地区龙潭组泥页岩具备良好的生气条件、储集条件和可压裂性,具有较大勘探潜力。

In order to identify the exploration prospect of shale gas in Longtan Formation in Zhina area,the mineral composition,organic geochemical characteristics,microscopic pore characteristics,thickness and distribution of bored mud shale and gas content characteristics of Z2 well Longtan Formation were analyzed,and the characteristics of shale gas reservoirs in Longtan Formation were studied and the exploration potential of shale gas was evaluated.The results show that the organic matter type of shale is typeⅡ_(2)-Ⅲ,and mainlyⅡ_(2),the total organic carbon content is 1.34%~8.25%,the average is 3.68%,and the maturity of organic matter is 0.92%~3.24%,with an average of 2.45%,which belongs to the high-high maturity evolution stage and has good vitality potential.The results of scanning electron microscopy show that the mud shale samples mainly develop four types of microscopic pores,including endogranular science,intergranular pores,organic matter pores and microfractures,and the internal pores are developed,which provid a good storage space for shale gas.The brittle mineral content of mud shale in Z2 well is 24.40%~63.08%,the average is 41.22%,the total thickness of mud shale is 170.74 m,accounting for 42%,and five mud shale layers with effective continuous thickness greater than 15 m are developed,and two shale sections can be formed with adjacent wells,which are suitable for fracturing transformation.The shale of Longtan Formation in Zhina area has good vitality conditions,reservoir conditions and fracturability,and has great exploration potential.