四川盆地太阳背斜浅层页岩气储层特征及试采评价

Shallow shale gas reservoir characteristics and pre-production performance analysis in Taiyang Anticline,Sichuan Basin

为深入认识埋深小于2000 m的浅层页岩气储层及开发特征,针对四川盆地昭通示范区太阳背斜五峰组-龙马溪组页岩开展了储层特征分析及试采评价。利用矿物组分、总有机碳含量、孔隙度及含气量实验测试和测井数据综合评价浅层页岩储层的可压性、生烃能力、储集性能及含气性,并对水平井试采特征和产能水平进行了分析预测。结果表明目的层五峰组-龙一11亚段脆性矿物含量65.1%~75.2%、TOC为2.10%~6.37%、孔隙度3.00%~8.01%、含气量1.63~7.23m3/t,纵向各小层品质由高至低依次为龙一11小层、五峰组、龙一12小层、龙一13小层和龙一14小层。浅层页岩气井试采动态表现为低压低产及低递减的开发特征,预测试采井EUR为2516×104m3,折算单位段长EUR为338×104m3/100m。随优质储层钻遇率及压裂规模增加,预期浅层页岩气具备更好的开发效果。

In order to further understanding the properties and production performances of shallow shale gas reservoir with a burial depth of less than 2000 m,the reservoir characterization and pre-production performance analysis were carried out for the WufengLongmaxi shale formation in the Taiyang anticline of Zhaotong demonstration area.The laboratory test and logging data of mineral composition,TOC,porosity and total gas content were used to comprehensively characterize the fracturing adaptability,hydrocarbon generation capacity,reservoir capacity and gas-bearing capacity.The shallow shale gas reservoir pre-production performances were also analyzed to preliminarily evaluate horizontal well productivity.According to the test and logging evaluation,the brittle mineral content of Wufeng-Long11 sub-member is 65.1%-75.2%,TOC is 2.10%-6.37%,porosity is 3.00%-8.01%and the total gas content is 1.63-7.23 m3/t,which indicate favorable development potential.In the longitudinal direction,the reservoir quality from high to low is Long111,Wufeng Formation,Long112,Long113 and Long114.The shallow shale gas reservoir pre-production shows a low-pressure,low-production and low production decline performance,and the estimated EUR of pre-production well is 2516×104 m3,and the corresponding EUR per 100-meter fractured section is 338×104 m3/100 m.With the improvement of drilling ratio and fracturing performance,the shallow shale gas reservoir could gain a favorable production performance and development potential.