摘要：

采出水回注是国内处理气田采出水的有效手段，但是，由于不同工艺处理效果存在差异，导致采出水中未被处理的部分悬浮物对回注地层造成不同程度的堵塞伤害。运用激光粒度衍射分析技术、室内物理流动模拟实验结合核磁共振技术，开展采出水回注室内模拟实验，定量评价采出水悬浮物对岩心样品的伤害程度，明确不同工艺处理效果，揭示回注地层堵塞伤害机理。实验结果表明，气田采出水悬浮物粒径尺度是影响回注地层堵塞程度的主控因素，发生堵塞伤害的悬浮物粒径主要分布在7.65~52.62 μm；采用“破乳+油水分离+沉降除油+气浮+旋流分离+过滤”工艺处理效果最佳，悬浮物粒径均值下降率为76.31%，中值下降率为77.46%，回注后地层渗透率伤害率仅为2.16%，孔隙度伤害率降至10.77%；而“沉降除油”工艺处理效果较差，核磁共振结果显示较小孔喉堵塞程度为24.15%，整体孔喉堵塞程度达到24.18%，回注后对地层渗透率伤害率达26.09%，孔隙度伤害率为13.64%。综合分析认为，采出水中的较大粒径悬浮物是造成回注地层发生堵塞伤害的主要原因，根据回注地层储层物性特征，针对性地选择高效的水处理工艺，是延长回注地层寿命，实现气田采出水高效回注的有效方法。

关键词: 采出水, 核磁共振, 处理工艺, 储层伤害, 苏里格气田

Abstract:

Produced water reinjection is an effective method for the treatment of produced water in gas fields in China. However，due to the differences in the treatment effects of different processes，the untreated suspended solids in the produced water cause varying degrees of clogging damage to the reinjected formation. Using laser particle size diffraction analysis technology，indoor physical flow simulation experiment combined with nuclear magnetic resonance technology，the laboratory simulation experiment of produced water re-injection was carried out to quantitatively evaluate the damage degree of produced water suspended matter to core samples，to clarify the treatment effects of different processes，and to reveal the formation blockage of re-injection damage mechanism. The experimental results showed that the particle size of the suspended solids in the produced water of the gas field was the main controlling factor affecting the plugging degree of the reinjection formation. And the experimental results showed that the particle size of the suspended solids with blockage damage is mainly distributed in the range of 7.65-52.62 μm. The combined process of demulsification，oil-water separation，sedimentation，air flotation，cyclone separation and filtration had the best effect. The average particle size decreased rate was 76.31%，the median decrease rate was 77.46%，and the formation permeability damage rate after reinjection was only 2.16%，the porosity damage rate was reduced to 10.77%，While the “settling and oil removal” process was less effective. The nuclear magnetic resonance results showed that the blockage degree of small pore throats was 24.15%，and the overall pore throat blockage degree reached 24.18%. The permeability damage rate was 26.09%，and the porosity damage rate was 13.64%. The comprehensive analysis showed that the larger particle size suspended solids in the produced water was the main reason for the blockage damage of the reinjection formation. According to the physical characteristics of the reinjection formation reservoir，the targeted improvement of the treatment effect of the large particle size suspended solids was the extension of the time. Reinjection formation life is an effective method to achieve efficient reinjection of produced water in gas fields.

Key words: produced water, nuclear magnetic resonance, treatment technology, reservoir damage, Sulige gas field

中图分类号: 

• X741