Low-permeability, low-production, low-abundance are the major features of the low-permeable gas reservoir. Commingling production has been widely used as an important method to improve the producing ability of gas reservoirs, however, the dynamic analysis and technical countermeasures for the multi-commingled wells are still not enough.

Started from the multi-commingled filtration theory model, the pressure characteristics and the contribution rate of production of each layer, which are under the different multi-commingled well conditions such as reservoir properties differences, interlayer pressure difference and different damage degree, are studied in this paper. The results show that the contribution rate is fixed on formation coefficient before the pressure wave reaches the boundary; and after that, it is fixed on the storage ratio, it could be fixed on the formation coefficient, storage ratio and kickoff pressure gradient when considering the kickoff pressure gradient. Although there are significant differences in permeability between layers, the well test pressure curves have little difference.

Taking the Da-niudi gas field for example, the single layer production rate, recovery and total recovery are studied by numerical simulation at different permeability ratio in multi-commingled well. The results show that the different permeability ratio contrast (<10) models can all be commingled. The total recovery of different models has little difference, when the formation pressure declines to the abandonment pressure. However, the smaller the permeability contrast is, the longer the stable production period of the well is, and the less the interlayer recovery difference is; on the contrary, the shorter the stable production period is, and the larger the interlayer recovery difference is.

All the reservoirs in the multi-commingled well had better to be put into operation at one time. In this way not only the operation to succeed the late fill-holes can be saved, but also overall commingled layer recovery could increase.

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