Qu Jie, Wang Pan, You Qing, Zhao Guang, Sun Yongpeng, Liu Yifei
School of Energy Resources, China University of Geosciences, Beijing 100083, China.
School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China.
Gels. 2022 Jun 5;8(6):352. doi: 10.3390/gels8060352.
Horizontal well water coning in offshore fields is one of the most common causes of rapid declines in crude oil production and, even more critical, can lead to oil well shut down. The offshore Y oil field with a water cut of 94.7% urgently needs horizontal well water control. However, it is a challenge for polymer gels to meet the requirements of low-temperature (55 °C) gelation and mobility to control water in a wider range. This paper introduced a novel polymer gel cross-linked by hydrolyzed polyacrylamide and chromium acetate and phenolic resin for water coning control of a horizontal well. The detailed gelant formula and treatment method of water coning control for a horizontal well in an offshore field was established. The optimized gelant formula was 0.300.45% HPAM + 0.300.5% phenolic resin + 0.100.15% chromium acetate, with corresponding gelation time of 2634 h at 55 °C. The results showed that this gel has a compact network structure and excellent creep property, and it can play an efficient water control role in the microscopic model. The thus-optimized gelants were successively injected with injection volumes of 500.0 m. The displacement fluid was used to displace gelants into the lost zone away from the oil zone. Then, the formed gel can be worked as the chemical packer in the oil-water interface to control water coning after shutting in for 4 days of gelation. The oil-field monitoring data indicated that the oil rate increased from 9.2 m/d to 20.0 m/d, the average water cut decreased to 60~70% after treatment, and the cumulative oil production could obtain 1.035 × 10 t instead of 3.9 × 10 t.
海上油田水平井水锥是原油产量迅速下降的最常见原因之一，更关键的是，可能导致油井停产。含水率为94.7%的海上Y油田迫切需要进行水平井水控。然而，聚合物凝胶要满足低温（55℃）成胶和在更宽范围内控水的流动性要求具有挑战性。本文介绍了一种由水解聚丙烯酰胺与醋酸铬和酚醛树脂交联而成的新型聚合物凝胶，用于水平井水锥控制。建立了海上油田水平井水锥控制的详细凝胶配方和处理方法。优化后的凝胶配方为0.300.45% HPAM + 0.300.5%酚醛树脂 + 0.100.15%醋酸铬，在55℃下相应的成胶时间为2634小时。结果表明，该凝胶具有致密的网络结构和优异的蠕变性能，在微观模型中能起到高效的控水作用。如此优化后的凝胶剂依次以500.0 m的注入量注入。用驱替液将凝胶剂驱替到远离油层的漏失层。然后，形成的凝胶在成胶4天关井后可作为油水界面的化学封隔器来控制水锥。油田监测数据表明，产油量从9.2 m³/d增至20.0 m³/d，处理后平均含水率降至60~70%，累计产油量可达1.035×10⁴ t，而不是3.9×10³ t。
