裂缝性致密砂岩储层井周液相时空分布规律

裂缝性致密砂岩气藏在各项工程作业过程中,工作液滤液侵入导致井周含水饱和度上升,储层水相圈闭损害,气相渗透率降低甚至为零。特别是在储层微裂缝发育带,在正压差钻完井作业过程中,工作液滤液将侵入到地层深部,致使测试或测井解释将储层含水饱和度解释偏高,将气层解释为气水同层或水层,延缓油气层的发现和开发。建立了综合利用地质参数和工程参数的裂缝性致密砂岩储层工作液滤液侵入数学模型,利用该模型模拟井周储层在作业过程中液相饱和度时空分布。研究结果揭示出,微裂缝的存在加快了滤液侵入速度,加大了滤液侵入深度,并显著提高微裂缝邻近基块的液相饱和度。

Study on the time-space distribution of liquid phase around wellbore in the fractured tight sandstone reservoir

During operations in fractured tight sandstone,filtration invasion may be lead to water phase trapping and increase water saturation in the near-well bore;this makes gas permeability decrease,even to zero.Particularly in the micro-fracture reservoir, the filtrate invasion will be deeper with positive pressure gradient.The reservoir contain high water saturation will be explained by the test or log result;the gas reservoir will be interpreted as a water zone or put off the gas reservoir discovery and develop...