缝洞型碳酸盐岩油藏堵水技术室内研究

为了遏制塔河油田奥陶系缝洞型碳酸盐岩油藏油井含水上升过快的趋势.针对塔河油田储集层条件,对两种有效堵剂(改性栲胶堵剂和柔性堵剂)进行了实验研究.研究结果表明,改性栲胶堵剂高温稳定性好、耐高矿化度盐水侵蚀;柔性堵剂在高温和高矿化度环境中可长期稳定,且易解堵,是封堵塔河油田奥陶系碳酸盐岩油藏出水缝洞的可选材料.利用两种堵剂进行缝洞型碳酸盐岩岩心封堵实验,结果表明:增大堵剂用量的初期主要使封堵层深度变大,突破压力梯度升高;当封堵层达到一定的深度后,堵剂堆积使流动通道变窄小,可大幅度提高残余阻力系数.图5表3参15

Laboratory study of water shutoff in the fracture-cavity carbonate reservoir

To restrain the too-fast rising of water cut in oil wells in Ordovician fracture-cavity carbonate reservoirs in Tahe Oilfield, two effective water shutoff agents (modified tannin gel water shutoff agent and flexible water shutoff agent) are studied in laboratory. The results indicate that the modified tannin gel water shutoff agent represents good stability at high temperature and resistance against the corrosion by high-salinity brine, and the flexible water shutoff agent may be long stable under high temperature and high-salinity circumstance and easily broken down, which is optional for shutting off the water exit fractures or caves in Ordovician carbonate reservoirs in Tahe Oilfield. The laboratory study of fracture-cavity carbonate cores plugged with the two agents shows that the increase of the agent injection leads to an increase of depth of plugging section and higher breakthrough pressure gradient in the initial stage; the accumulation of the shutoff agent makes the flow path narrower when a certain depth of plugging section is reached, raising the residual resistant factor.