贵州岑巩TX1井牛蹄塘组页岩压裂效果评价
Well TX1 Fracturing Effect Evaluation of Niutitang Formation Shale in Cengong, Guizhou

TX1井是四川盆地外围第一口针对牛蹄塘组页岩压裂的井，岩心现场解析含气量为1.00～3.06m3/t，含气性较好，展现了较好的勘探前景.但复杂构造以及下部含水层对后期储层改造提供了挑战.对TX1井进行了压裂改造，返排过程中气体点火2～3m，但后期一直出水，返排率大于100%.利用Meyer软件进行压裂拟合评价，结果显示TX1井在压裂过程中因沟通了底部高含水层，导致压后出水严重；压裂改造未形成复杂的裂缝网络，限制了储层改造的效果.因此认为直井压裂改造受体积的限制，只能作为对页岩储层含气性与产能的评价手段，页岩气商业性开发还需通过水平井钻井和大规模的分段压裂改造来实现.该井的钻探施工与压裂改造经验为本地区下一步勘探开发指明了方向.
Well TX1 is the first well aimed at Niutitang Formation that was fractured outside of Sichuan basin. The field gas content of well TX1 core in Guizhou Cengong area is high at 1.00 to 3.06m3/t, showing good exploration prospect of Niutitang shale gas. But the complex structure and the lower aquifer provide a challenge to the later reservoir reconstruction. In order to further evaluate the gas bearing and production capacity of well TX1, we obtain the gas flame reaching 2 to 3 meters high after fracturing and postfrac flowback. But the flowback water is higher than 100%. This paper analyzes the cause of water and fracturing effect through evaluating the reservoir geological characteristics and fracturing fitting. The evaluation shows that the high water flowback resulted as the fracture linked up the bottom high water aquifers during fracturing process. No complex fracture network has been formed by the fracturing fitting result, which limits the reservoir reconstruction effect. From this we can see that vertical well fracturing effect is limited by fracturing size, it can only be used for reservoir and production evaluation. Horizontal wells and large scale staged fracturing are needed for commercial development. The drilling and fracturing of well TX1 can facilitate further exploration in this area