Well TX1 Fracturing Effect Evaluation of Niutitang Formation Shale in Cengong, Guizhou

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.