Change of phase state during multi-cycle injection and production process of condensate gas reservoir based underground gas storage

TANG Yong,LONG Keji,WANG Jieming,XU Hongcheng,WANG Yong,HE Youwei,SHI Lei,ZHU Huayin

Table 4 Composition of remaining oil at the end (10 MPa) of multi-cycle production in underground gas storage.

Composition Mole fraction of produced fluid at 4 MPa/% Mole fraction of remaining fluid at the end of each cycle/% Cycle 1 Cycle 2 Cycle 3 Cycle 4 Cycle 5 CO2 0.58 0.09 0.04 0.01 0 0 N2 1.19 0.24 0.15 0.09 0.08 0.07 C1 66.95 86.85 88.82 91.14 91.97 92.05 C2 9.78 6.28 5.92 5.69 5.63 5.62 C3 4.54 2.28 2.05 1.87 1.82 1.81 iC4 0.39 0.07 0.03 0.01 0.00 0.00 nC4 0.21 0.26 0.26 0.26 0.25 0.25 iC5 0.55 0.10 0.05 0.01 0.01 0 nC5 0.09 0.02 0.01 0 0 0 C6 0.68 0.13 0.06 0.02 0 0 C7 4.52 0.88 0.47 0.13 0.03 0.02 C8 2.12 0.44 0.25 0.07 0.02 0.01 C9 1.59 0.36 0.22 0.06 0.02 0.01 C10 1.46 0.36 0.24 0.07 0.02 0.01 C11+ 5.36 1.66 1.43 0.57 0.16 0.12