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Abstract Inflow performance relationship(IPR) in single-phase(water) coalbed methane wells provides the basis for the reasonable operating practice and dynamic analysis. The mathematical models of IPRs for Darcy and non-Darcy flow in coalbed methane(CBM) wells are developed based on the fluid mechanism in porous medium. The IPR curves are obtained with the field examples in Ordos Basin. The results show that the small errors of less than 12% between the prediction and measured values are achieved due to the reservoir parameters，fluid physical property and non-Darcy skin factor. The IPR should be analyzed by the Darcy model with constant supply boundary pressures for the low flow velocity. However，the non-Darcy model should be involved while the Reynolds number is over 0.3 and water production is more than 30 m3/d. During the initial pumping production，the water flow rate and coal particle migration can be controlled due to the increase of pressure drop，which is beneficial to water flow. And an increased pressure drop from 0.44 MPa up to 3.68 MPa leads to the enhanced water production from 10 m3/d to 40 m3/d. The increase in the integrated flow conductivity of coalbed and deliverability occurs with the increment of permeability. And the increase of permeability from 0.9×10－3 ?m2 up to 6.15×10－3 ?m2 leads to an increment in water production from 3.5 m3/d to 15.9 m3/d. The decrease of skin factor makes the IPR curves move towards the right direction. And the reduction in skin factor from －3.10 to －4.85 yields the increase of water production from 34.8 m3/d up to 45.6 m3/d.
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Received: 10 December 2010
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2011, Vol. 30 
