Experimental Study on the Forcible Imbibition Law of Water in Shale Gas Reservoirs

Water imbibition is a key factor affecting the flowback regime of shale gas wells after volume fracturing. In this study, set experimental apparatus and corresponding test evaluation methods were developed to analyze laws forcible water in reservoir, characterize initiation time microfractures induced by hydration quantitatively, optimize shut-in wells; depths different pore types are quantitatively calculated based on multiple analytical model. The results show that: according saturation growth rate, can be divided into three periods, diffusion, transition, balance. Among them, diffusion period main for capacity rise. reason phenomenon that due fluid pressure difference effect, fills its large pores rapidly early stage, percolation transition period, rate decreases continuously gradual increase saturation. Due Jamin it difficult enter small roar channel, seepage tends stabilize, equilibrium appears. shut-in, increases significantly under action pressure, providing amount spontaneous later. depth clay was much greater than brittle mineral an organic pore. reservoir confining has prohibition imbibition, but even still improve fracturing effect resulting porosity 0.42–1.63 times permeability 17.6–67.3 times. Under conditions, 98.5 h average negative correlation with capacity. On basis, optimized shortest well 5 days. study provide scientific basis optimization reservoirs.