Effect of drawdown pressure on water production in gas reservoir

Abstract

The water production is widespread in the exploitation of gas reservoir. The drawdown pressure is the main force that drives the formation water. Based on the integration of relative permeability curve and mercury intrusion curve, the analysis of the effect of drawdown pressure on the water production is conducted. As shown by the research result, when the drawdown pressure is different, the water that starts to flow belongs to distinct category, and the water producing degree varies. Larger drawdown pressure results in higher water producing degree. If P2<P0, the produced water merely contains condensate water; if P0<P2<P1, the produced water includes condensate water and free water; if P1<P2, the produced water contains condensate water, free water and movable water as components, where P0 and P1 represent drawdown pressures corresponding to the original water saturation and irreducible water saturation respectively, and P2 represents the practical drawdown pressure. Directly affected by the exploitation condition, the formation water production can be controlled by constraining the drawdown pressure. The research result can provide the reference for the management of water-producing well in gas reservoir.