Stress sensitivity of multiscale pore structure of shale gas reservoir under fracturing fluid imbibition

Generally, huge amounts of fracturing fluid are used in a shale gas well but the flowback efficiency is low. Since distribution characteristics imbibed complex, they need further evaluation. This paper takes Longmaxi Shale as research object, including matrix cores, natural fracture cores and artificial with proppant. Stress sensitivity experiments carried out on above three kinds under different degrees imbibition retention state fluid. The results show that when degree aqueous phase 0-0.78 pore volume, water mainly appears pores diameter 2-50 nm. As saturation increases to more than 0.9 or fractures hydraulic 100-1,000 nm larger 1,000 increase significantly. Both stress nanopores enhanced by retention. With effective stress, permeability damage rate proppant inversely proportional Aqueous significantly contributes cores. 100 It recommended reservoir should be controlled below 0.5 volume. In this case, will less aggravated retention, reduced certain extent. Cited as: Chen, M., Yan, Kang, Y., Cao, W., Bai, J., Li, P. multiscale structure imbibition. Capillarity, 2023, 8(1): 11-22. https://doi.org/10.46690/capi.2023.07.02