大型CO_2压裂技术在孤北地区深层气勘探中的应用

APPLICATION OF CO_2 FRACTURING TECHNIQUE IN COAL-BED METHANE EXPLORATION IN GUBEI REGION

孤北地区地层储层具有以下特点:高压、高温,储层类型为极低渗透均质砂岩储层,岩性致密,地层物性极差,渗透率极低,并存在不同程度的伤害,其中孤北古1井渗透率仅为0.018×10-3μm2,表皮系数25.6,存在严重伤害。而煤层气与常规气藏的开采特性不同,它与渗透率的大小密切相关。针对该地区的地层特点,相应地采用CO2压裂技术,进行地层改造,提高渗透率,增加煤层气的产出,取得了良好的效果。

The reservoir of Gubei region has the characteristics of high pressure and high temperature. Reservoir type belonged to tight homogeneous sandstone. It has the features of tight lithologic, poor formation physical property and low permeability, and reservoir is polluted seriously. Permeability is 0.018md of and skin factor is 25.6 in well Gubei 1. Production features of coal - bed methane are different from the normal gas reservoir. It is closely related to permeability. According to strata characteristics of this region, in order to increase permeability and raise the output of coal - bed methane, the CO2 fracturing technique is adopted and is obtained good effect. Not only clearer cognition of deep zone coal-bed methane in Gubei area contained, but also high production of gas discovered in well Gubei 1.