中国海油CCS示范项目超浅层大位移井固井实践

Cementing Practice of Ultra-Shallow Extended Reach well of CNOOC CCS Demonstration Project

CCS技术是Carbon Capture and Storage的缩写,是一项将二氧化碳(CO_(2))捕获和封存的技术,是稳定大气温室气体浓度减缓行动组合中的一种选择方案。中国海油CCS示范项目利用一口超浅层大位移井,将油田开发过程中高含量二氧化碳原位处置回注至类似“穹顶”地质构造,以达到二氧化碳封存的目的。目标井深度3709 m,垂深仅894.31 m,水平段延伸长度3212.96 m,水垂比达3.59,是一口超浅层大位移水平井。固井专业面临低温泥饼不易冲洗、长尾管段回接居中度差和插入难、水泥环易腐蚀和难修复、浅层疏松地层易漏等技术难题。中海油服发挥自身技术优势,对技术难题一一化解,保障了示范项目成功实施。2023年6月,伴随着回注系统将二氧化碳以每小时9吨的速度回注至地层,中国海油CCS示范项目正式投产,作为中国海油自主设计的首口回注井,标志着我国初步形成了海上二氧化碳注入、封存和监测的全套钻完井技术和装备体系,填补了我国海上二氧化碳封存技术的空白。

CCS(Carbon Capture and Storage)is a technology that captures and stores carbon dioxide(CO_(2))as one option in a portfolio of mitigation actions to stabilize atmospheric greenhouse gas concentrations.CNOOC CCS demonstration project uses an ultra-shallow extended reach well to dispose of high-content carbon dioxide in situ during oilfield development and re-inject it into geological structures similar to"dome",which has achieved the purpose of carbon dioxide storage.This well is an ultra-shallow extended horizontal well with a depth of 3709 m,vertical depth of only 894.31 m,horizontal section extension length of 3212.96 m,and water-sag ratio of 3.59.The cementing specialty faces technical problems such as low temperature mud cake not easy to wash,medium poor connection and insertion difficulty of long tail section,easy corrosion and repair of cement ring,and easy leakage of shallow loose formation.Cosl has made full use of its technical advantages to solve technical problems one by one and ensure the successful implementation of demonstration projects.In June 2023,with the reinjection system reinjecting carbon dioxide to the formation at a rate of 9 tons per hour,CNOOC CCS demonstration project was officially put into operation.As the first re-injection well independently designed by CNOOC,it marks the initial formation of a full set of drilling and completion technology and equipment system for offshore carbon dioxide injection,storage and monitoring in China.It fills the gap of carbon dioxide storage technology at sea in China.