非达西渗流对低渗透气藏气水同产水平井产能的影响

水驱气藏开采到一定程度就会产水,此时出现的气水两相流动会增大气体渗流阻力,使气井产量急剧下降.气井产能的确定是科学合理开发气田的基础,对气井的配产具有重要的指导意义.根据气水两相渗流规律的变化,基于稳定渗流理论,引入了气水两相拟压力以及两相拟启动压力梯度,建立了启动压力梯度、滑脱效应、应力敏感、地层伤害以及近井地带高速非达西影响的低渗透气藏气水同产水平井产能方程.研究表明：生产水气比对气井产能影响最大,在气井生产过程中应尽量控制气井见水;随着启动压力梯度、应力敏感和生产水气比的增大,气井产能不断降低;随着滑脱因子增大,气井产能不断增加;在启动压力梯度对气井产能的影响中,气相启动压力梯度比水相启动压力梯度所占的权重更大.

Influence of non-Darcy flow on deliverability of gas-water producing horizontal well in low permeability gas reservoirs

When water drive gas reservoir is exploited to a certain extent, the water will be produced, and then gas and water two-phase flow will increase the resistance of gas flow, which leads a sharp decline on gas well production. The determination of reasonable gas well deliverability is the foundation of scientific development of gas field and has very important guiding significance. According to the change of gas and water two-phase seepage rule, based on stable percolation theory, this paper introduced pseudopressure and threshold pressure gradient of gas and water two-phase, and established a new gas well productivity prediction model for gas-water producing horizontal wells, taking the influences of threshold pressure gradient, slippage effect, stress sensitivity, formation damage and high-speed non- Darcy into account. Studies show that the water/gas ratio has a rather greater impact on the deliverability of gas well, so water breakthrough must be controlled during the gas production. With the increasing of threshold pressure gradient, stress sensitivity and water/gas ratio, the deliverability of gas well decreases, while with the decreasing of slippage effect, the deliverability of gas well increases. The gas phase threshold pressure gradient plays a more important influence on the gas deliverability than water phase threshold pressure gradient.