基于渗透率损失规律分析的稠油井割缝筛管割缝宽度优化

新疆油田某油区内出砂稠油热采井普遍采用割缝筛管进行简易防砂，割缝筛管缝宽设计缺乏依据，防砂后油井产能损失严重，亟需开展割缝筛管缝宽设计的相关研究。模拟目标油区稠油、地层水携砂流动与地层砂条件开展割缝筛管挡砂堵塞实验，分析不同缝宽割缝筛管在稠油堵塞以及稠油与地层砂复合堵塞条件下渗透率变化规律与挡砂情况，结合防砂性能指标定量评价完成缝宽优化。研究结果表明，割缝筛管在稠油堵塞和复合堵塞阶段均发生明显的渗透率损失，堵塞平衡后筛管渗透率均降至0.3 μm2以下；提高割缝宽度，筛管在挡砂过程中渗透率增高，渗透率损失幅度和损失速度均呈现降低趋势，但降低缝宽有利于提高筛管挡砂率；对于目标油区中值粒径0.25 mm地层砂，割缝宽度0.30 mm筛管综合防砂性能最好。割缝宽度的优化研究考虑了稠油热采井出砂时间，可为该类油井防砂后产能评价与防砂介质精度优化提供参考和借鉴。

Optimization study on the slot width of slotted screen in heavy oil wells based on permeability loss law analysis

In one certain oil area of Xinjiang Oilfield, slotted screen is generally adopted in sand-production heavy oil thermal recovery wells for simple sand control, but the slot width design of slotted screen is absent of basis, which leads to the serious loss of oil well productivity after sand control. Therefore, it is in urgent need to carry out the studies related to the slot width design of slotted screen. The sand retention and plugging experiment of slotted screen was carried out by simulating the heavy oil, formation water carrying sand flow and formation sand conditions of the target oil area. Then, the permeability change laws and sand retention situations of slotted screens with different slot widths under the conditions of heavy oil plugging and combined heavy oil and formation sand plugging were analyzed. Finally, slot width was optimized based on the quantitative evaluation of sand control performance indexes. It is indicated that slotted screen permeability decreases significantly in heavy oil plugging stage and combined plugging stage and it drops to less than 0.3 μm2 after the plugging reaches the balance state. With the increase of the slot width, the permeability increases in the process of sand retention and both permeability loss amplitude and permeability loss velocity present the trend of decreasing, but the reduction of slot width is beneficial to increase screen’s sand retaining ratio. As far as the formation sand with median particle size of 0.25 mm in the target oil area is concerned, the comprehensive sand control performance of the screen with slot width of 0.30 mm is the best. This study takes the sand production time of heavy oil thermal recovery wells into consideration and it can provide a reference for the productivity evaluation of similar oil wells after sand control and the optimization of sand control medium accuracy.