Practice and understanding of fracturing in Weirong shale gas field

Abstract

Compared to the middle and shallow strata, the engineering geological characteristics of Weirong deep shale gas are more complex, with the four characteristics of high ground stress, high horizontal stress difference, high plasticity, and high formation pressure. The complex engineering geological characteristics bring three major challenges: difficulty in forming complex fracture networks, difficulty in supporting and maintaining artificial fractures, and frequent occurrence of abnormal situations such as casing deformation. The specific performance result is the low single well EUR after gas well fracturing. Through unremitting exploration and practice, the fracturing technology has been continuously improved in the process of discovering and solving problems, and a series of measures of "fine optimization, real-time warning, operating pace control, and W-shaped well network" for preventing casing deformation and increasing post fracturing output has been formed based on the concept of balanced fracturing. The technology has been promoted and applied in 39 wells, and the fracturing effect has been continuously improved, with an average EUR increase of 500×104 m3 per well, and a decrease of casing deformation rate from 42.4% in 2022 to 16.67% at present. Due to the impact of the production of adjacent old wells on the production of newly fractured production wells, the output of new wells after fracturing is lower than the previous stage. With the existing well spacing of 400 m (Phase Ⅰ)/300 m (Phase Ⅱ), there is room for reduction and optimization in fracturing scale. Subsequent new wells should be differentiated and optimized based on remaining reserves, and research on fracturing technology shall be carried out continuously, achieving the beneficial development of Weirong deep shale gas.

Keywords

• fracturing technology
• casing deformation
• benefit development
• gas field development
• weirong shale gas field