Research on the Fracturing Technology of Three Steps Method for Tight Sandstone Gas: A Case Study in Songliao Basin, China

Abstract Tight sandstone gas is the main gas source for increasing storage and production in Songliao Basin, China. Due to the deep burial depth, poor physical properties, and small pore throats of the reservoir, large-scale fracture network fracturing leads to uncontrolled fracture height, resulting in effective fracture length, limited coverage, and poor stable production capacity. A "three Steps Method" fracturing technology has been developed based on the concept that "fracture-controlled reserves are well-controlled reserves". three-stage fracture network stimulation technology controls near fractures and expands far fractures, conducting the network fracturing by taking advantage of the relationship between the two-dimensional stress difference of reservoirs and the net pressure of fracture extension. This technology splits fracturing into three stages: fracture forming stage, network forming stage, and fracture supporting stage. In this paper, the "Three Steps Method" fracture network stimulation technology is implemented in the YS303-3 well. The underground microseismic monitoring data are used to compare the high displacement fracture network stimulation of adjacent wells. The results show that the length and width of the fractures in the well after implementing the technique increased by 1 and 0.7 times, respectively. The volume of the stimulated reservoir increases by twofold and the daily gas production of this well rises to 3.9×104m3, marking an increase of 30% in gas production compared to the adjacent well. The three-step fracturing method is subsequently applied to 6 wells, which increases the average stable gas production to 5.3×104m3 per well, accounting for a production increase of over 50%. The "three Steps Method" fracture network stimulation has emerged as a critical method for optimizing storage and production in tight gas reservoirs. It offers opportunities for advancement and implementation, providing technical support and reference for the effective utilization of unconventional resources.