中国CO_(2)-EOR油田生产碳强度多技术情景建模与核算研究

Multi-scenario modeling and estimating of carbon intensity in China’s CO_(2)-EOR oilfields

碳中和目标开启了能源系统深度脱碳之路,而国内油气资源勘探开发的力度仍持续增加,因此油气资源开发利用全过程将成为能源系统脱碳的重点领域。CO_(2)-EOR技术用于提高油气采收率的同时可实现CO_(2)地质封存的巨大潜力备受关注,国内陆续在松辽盆地、渤海湾盆地、鄂尔多斯盆地、准格尔盆地等主要含油气盆地内开展了多个CO_(2)-EOR项目。本研究以大庆油田、长庆油田、新疆油田、吉林油田、胜利油田、中原油田、江苏油田和延长石油开展CO_(2)-EOR的8个生产区块为研究对象,基于自底向上的工程视角碳排放分析方法,包括勘探、钻完井、开采、处理及油田集输五个阶段建模分析油田生产区块从2000年到2021年的生产碳排放变化趋势,并在CO_(2)连续注入与水气交替注入两种开发方式下分析CO_(2)驱完全替代水驱开发油田的碳强度变化。结果表明:(1)由于资源衰竭致使开采用能需求上升,大部分油田区块2000年以后的生产碳强度呈缓慢上升趋势,从2000开始到2014生产碳排放总量随着石油产量的上升一直在增加,2021年8个油田区块的生产碳排放总量为308.85万吨CO_(2)eq;(2)无论是在CO_(2)连续注入技术情景,还是在水气交替注入情景下,当注入CO_(2)封存比例大于30%以后,生产碳强度逐渐由正值变为负值,成为生产过程中CO_(2)净负排放的油田。CO_(2)驱提高采收率技术作为CCUS技术的重要组成部份,将在未来油气能源系统脱碳中发挥至关重要的作用,未来应进一步扩大CO_(2)-EOR项目的试验、生产及应用规模。

The goal of carbon neutrality opens the way for the deep decarbonization of the energy system.However,the exploration and development of domestic oil and gas resources continue to increase,so the development of oil and gas resources will become one of the key directions for the decarbonization of the energy system.The huge potential of CO_(2)-EOR to enhance oil and gas recovery and realize CO_(2) geological storage has attracted much attention.The CO_(2)-EOR projects have been carried out in China's Songliao,Bohai Bay,Ordos,and Jungeer Basins,etc.In this study,eight blocks of CO_(2)-EOR in the Daqing,Changqing,Xinjiang,Jilin,Shengli,Zhongyuan and Jiangsu Oilfields and Yanchang Petroleum were selected.Based on the carbon emission analysis framework from the bottom-up engineering perspective,modeling stages including exploration,drilling and completion,extraction,treatment and transportation were included to analyze the trend of production carbon emissions from 2000 to 2021 in the oilfields,further to analyze the change of carbon intensity of CO_(2) flooding completely replacing water flooding under two technical scenarios:continuous CO_(2) injection and alternating water and gas injection.The results show that:(1)Due to the increase of energy demand caused by resource exhaustion,the carbon intensity of production in most oil fields showed a slow upward trend after 2000,and the total upstream carbon emission increased with increments of oil production from 2000 to 2014.In 2021,the total upstream carbon emission in 8 oil fields was 3,088,500 tonnes CO_(2)eq.(2)Regardless of the scenario of either continuous CO_(2) injection or alternate water and gas injection,when the proportion of CO_(2) injection and sequestration is greater than 30%,the carbon intensity of production gradually changes from positive to negative,and it becomes an oilfield with net negative CO_(2) emission in the production process.As an important part of carbon capture,usage and storage(CCUS)technology,CO_(2)-EOR technology will play a crucial role in the future decarbonization of oil and gas energy systems.The scale of trial,production and promotion of CO_(2)-EOR projects should be further expanded in the future.