渤海稠油热采隔热管优选和注氮工艺优化

渤海油田热采井已进行多轮次蒸汽吞吐，优化井筒隔热技术已成为热采井注汽中关键的技术之一。目前渤海油田L油田A23井已进行了三轮次的蒸汽吞吐现场作业，其中第三轮次注汽管柱在第二轮次注汽基础上进行了优化改进，采用了4-1/2″气凝胶隔热油管注汽工艺，较A23井二轮次使用的高真空隔热油管，有效降低隔热油管每千米的热损失由14.24%降为10.21%；同时采用了环空井筒间歇注氮工艺，降低井筒环空热损，较上一轮次有效地降低了11.86%的总注氮量。通过使用气凝胶隔热油管及环空间歇注氮工艺，降低了注汽井筒热损失，有效地节约了海上热采井注汽成本。

Optimization of Heat-insulating Pipes for Thermal Recovery of Heavy Oil in Bohai Sea and Optimization of Nitrogen Injection Technology

The thermal recovery wells in Bohai Oilfield have been subjected to multiple rounds of thermal recovery, and optimizing wellbore insulation technology has become one of the most critical technologies in thermal recovery steam injection. At present, the A23 well in the L oilfield of Bohai Oilfield has carried out three rounds of steam stimulation on-site operation, and the third round of steam injection has been optimized and improved on the basis of the second round of steam injection, using 4-1/2″ aerogel insulated tubing steam injection. Comparing with high vacuum insulated tubing used in the second round of Well A23, the second steam injection effectively reduces the heat loss per kilometer of insulated tubing from 14.24% to 10.21%. Meanwhile, the intermittent nitrogen injection process in the empty wellbore reduces the heat loss in the wellbore annulus and effectively reduces the total nitrogen injection volume by 11.86% compared with the previous round. By using aerogel insulated tubing and annulus intermittent nitrogen injection technology, the heat loss of steam injection is reduced and the cost of steam injection for offshore thermal recovery wells is effectively saved.