I. Introduction On February 20th, the large - scale sand - adding fracturing operation was successfully completed in Well HF on the side of Tiebei - 1 in the northeastern Sichuan oilfield work area. This well is the first ultra - deep shale gas horizontal well in the oilfield, which is of great milestone significance. Its total drilled depth is 6,898.0 meters, and the vertical depth is 5,311.2 meters. It is currently the deepest marine shale gas well in China. The fracturing operation of this well faces many problems and challenges.
II. Problems Faced Since the start of the drilling construction, Well HF on the side of Tiebei - 1 has encountered a series of problems. First, the deep burial depth and small casing size increase the difficulty and risk of construction. Second, the high formation stress and many limestone interlayers put forward higher requirements for the fracturing process. Third, the large difference in two - way stresses and the under - development of natural fractures make it difficult to improve the fracturing effect. These problems are listed as "Well No. 1" in 2025, highlighting their importance and urgency.
III. Fracturing Processes and Measures (1) Fracturing Process Experts proposed a process of "multiple sections with fewer clusters, gel fluid for fracture expansion, and multi - particle - size graded propping", which effectively copes with the formation complexity. (2) Fracturing Operation Measures Adopt high - temperature - resistant and high - drag - reducing fracturing fluid systems and post - perforation measures to reduce the construction pressure. Through the combination of high - viscosity fluid for fracture expansion and double temporary plugging technologies, increase the fracture height and complexity. Optimize multi - particle - size high - strength proppants to significantly improve the long - term flow - conducting capacity of complex fracture networks. Boldly use 175 - megapascal ultra - high - pressure fracturing equipment to increase the construction displacement from 10 cubic meters per minute to 16 cubic meters per minute, breaking through the previous limit of 140 - megapascal fracturing wellhead.
IV. Guarantee Measures (1) Organization and Coordination Guarantee To ensure the smooth implementation of fracturing, a special fracturing and gas - testing class was established, with 8 working groups set up. Professional technicians coordinated the safe and efficient operation of multiple specialized teams as a whole. (2) Work Mechanism Guarantee Innovate the work mechanism and strictly implement the "five - list - based" management and operation mode to achieve "five in - place", ensuring that all aspects of fracturing organization and coordination, technical support, and operation guarantee are in place. (3) Data Management Guarantee Successfully research on the "mountainous - area low - latency data transmission technology", independently develop and innovatively deploy the "high - efficiency data automatic acquisition system", ensure the accurate acquisition, safe transmission, and scientific management of fracturing data, and provide a solid foundation for the subsequent analysis and decision - making of fracturing data.
V. Fracturing Results During the intense and long - term fracturing construction, a total of 28 fracturing sections were completed, with the total fluid volume into the well being nearly 80,000 cubic meters and the total sand - adding volume being nearly 4,000 cubic meters, and the highest pump pressure was 135 megapascals. The successful fracturing of this well indicates that the oilfield has the ability to conduct 175 - megapascal ultra - high - pressure fracturing construction, explores a scientific path for the efficient exploration of deep - layer marine shale gas reservoirs in the northeastern Sichuan work area, provides engineering and technical support for the expansion of shale gas exploration to new strata systems and new types, and also accumulates valuable experience for the subsequent fracturing of ultra - high - pressure horizontal wells in the oilfield.
VI. Conclusion The fracturing operation of Well HF on the side of Tiebei - 1 has been successfully completed, demonstrating the technical strength and innovation ability of the oilfield in the field of ultra - deep shale gas well fracturing. This result will provide important reference and support for the further development of the oilfield in the shale gas field and promote the continuous progress of China's shale gas industry.