Effects of CH_(4)/CO_(2) multi-component gas on components and properties of tight oil during CO_(2) utilization and storage: Physical experiment and composition numerical simulation

An essential technology of carbon capture, utilization and storage-enhanced oil recovery (CCUS-EOR) for tight oil reservoirs is CO_(2) huff-puff followed by associated produced gas reinjection. In this paper, the effects of multi-component gas on the properties and components of tight oil are studied. First, the core displacement experiments using the CH_(4)/CO_(2) multi-component gas are conducted to determine the oil displacement efficiency under different CO_(2) and CH_(4) ratios. Then, a viscometer and a liquid density balance are used to investigate the change characteristics of oil viscosity and density after multi-component gas displacement with different CO_(2) and CH_(4) ratios. In addition, a laboratory scale numerical model is established to validate the experimental results. Finally, a composition model of multi-stage fractured horizontal well in tight oil reservoir considering nano-confinement effects is established to investigate the effects of multi-component gas on the components of produced dead oil and formation crude oil. The experimental results show that the oil displacement efficiency of multi-component gas displacement is greater than that of single-component gas displacement. The CH_(4) decreases the viscosity and density of light oil, while CO_(2) decreases the viscosity but increases the density. And the numerical simulation results show that CO_(2) extracts more heavy components from the liquid phase into the vapor phase, while CH_(4) extracts more light components from the liquid phase into the vapor phase during cyclic gas injection. The multi-component gas can extract both the light components and the heavy components from oil, and the balanced production of each component can be achieved by using multi-component gas huff-puff.

A review of interaction mechanisms and microscopic simulation methods for CO_(2)-water-rock system

This work systematically reviews the complex mechanisms of CO_(2)-water-rock interactions,microscopic simulations of reactive transport(dissolution,precipitation and precipitate migration)in porous media,and microscopic simulations of CO_(2)-water-rock system.The work points out the key issues in current research and provides suggestions for future research.After injection of CO_(2) into underground reservoirs,not only conventional pressure-driven flow and mass transfer processes occur,but also special physicochemical phenomena like dissolution,precipitation,and precipitate migration.The coupling of these processes causes complex changes in permeability and porosity parameters of the porous media.Pore-scale microscopic flow simulations can provide detailed information within the three-dimensional pore and throat space and explicitly observe changes in the fluid-solid interfaces of porous media during reactions.At present,the research has limitations in the decoupling of complex mechanisms,characterization of differential multi-mineral reactions,precipitation generation mechanisms and characterization(crystal nucleation and mineral detachment),simulation methods for precipitation-fluid interaction,and coupling mechanisms of multiple physicochemical processes.In future studies,it is essential to innovate experimental methods to decouple“dissolution-precipitation-precipitate migration”processes,improve the accuracy of experimental testing of minerals geochemical reaction-related parameters,build reliable characterization of various precipitation types,establish precipitation-fluid interaction simulation methods,coordinate the boundary conditions of different physicochemical processes,and,finally,achieve coupled flow simulation of“dissolution-precipitation-precipitate migration”within CO_(2)-water-rock systems.

An Integrated Framework for Geothermal Energy Storage with CO_(2)Sequestration and Utilization

Subsurface geothermal energy storage has greater potential than other energy storage strategies in terms of capacity scale and time duration.Carbon dioxide(CO_(2))is regarded as a potential medium for energy storage due to its superior thermal properties.Moreover,the use of CO_(2)plumes for geothermal energy storage mitigates the greenhouse effect by storing CO_(2)in geological bodies.In this work,an integrated framework is proposed for synergistic geothermal energy storage and CO_(2)sequestration and utilization.Within this framework,CO_(2)is first injected into geothermal layers for energy accumulation.The resultant high-energy CO_(2)is then introduced into a target oil reservoir for CO_(2)utilization and geothermal energy storage.As a result,CO_(2)is sequestrated in the geological oil reservoir body.The results show that,as high-energy CO_(2)is injected,the average temperature of the whole target reservoir is greatly increased.With the assistance of geothermal energy,the geological utilization efficiency of CO_(2)is higher,resulting in a 10.1%increase in oil displacement efficiency.According to a storage-potential assessment of the simulated CO_(2)site,110 years after the CO_(2)injection,the utilization efficiency of the geological body will be as high as 91.2%,and the final injection quantity of the CO_(2)in the site will be as high as 9.529×10^(8)t.After 1000 years sequestration,the supercritical phase dominates in CO_(2)sequestration,followed by the liquid phase and then the mineralized phase.In addition,CO_(2)sequestration accounting for dissolution trapping increases significantly due to the presence of residual oil.More importantly,CO_(2)exhibits excellent performance in storing geothermal energy on a large scale;for example,the total energy stored in the studied geological body can provide the yearly energy supply for over 3.5×10^(7) normal households.Application of this integrated approach holds great significance for large-scale geothermal energy storage and the achievement of carbon neutrality.

Preface to Special Issue: CO_2 capture storage and utilization

Reducing the anthropogenic COemissions from fossil resource combustion and human activities has become one of the major challenges we are facing today.Beyond those practical applications for the utilization of CO,such as the synthesis of salicylic acid,methanol,urea,NaHCO-NaCOchemicals and recently developed polycarbonate synthesis,scientists are still seeking new materials and technologies for efficient capture,

海洋CO_(2)地质封存研究进展与发展趋势

CO_(2)捕集、利用和封存是中国实现“双碳”目标的核心技术,也是全球研究的热点。CO_(2)地质封存是其中的关键环节,特别是海洋CO_(2)地质封存是今后的重点发展方向。以国内外海洋CO_(2)地质封存的发展历程为基础,结合典型CO_(2)海洋封存示范项目案例,系统梳理了国内外海洋CO_(2)地质封存理论研究进展,分析了CO_(2)在井筒流动、相变与传热、CO_(2)流体运移与储层物性参数展布规律、海洋地质封存机制及封存潜力、地质封存盖层完整性及安全性评估等方面的研究现状。认识到中国目前对海底地质结构中CO_(2)注入过程的多相态转化、溶解、捕获传质特征及动力学特性认识尚浅,对海洋封存机制及不同封存机制之间的相互作用机理尚不明确,未来应开展海洋CO_(2)动态地质封存空间重构机制研究,解决地质封存相态转化及流体动态迁移机理等关键科学问题,揭示海洋CO_(2)地质封存机制的相互作用机理,形成适用于中国海洋地质封存CO_(2)高效注入和增效封存方法。

Simultaneous CO_(2) capture and thermochemical heat storage by modified carbide slag in coupled calcium looping and CaO/Ca(OH)2 cycles

The simultaneous CO_(2) capture and heat storage performances of the modified carbide slag with byproduct of biodiesel were investigated in the process coupled calcium looping and CaO/Ca(OH)2 thermochemical heat storage using air as the heat transfer fluid.The modified carbide slag with by-product of biodiesel exhibits superior CO_(2) capture and heat storage capacities in the coupled calcium looping and heat storage cycles.The hydration conversion and heat storage density of the modified carbide slag after 30 heat storage cycles are 0.65 mol·mol^(-1) and 1.14 GJ·t^(-1),respectively,which are 1.6 times as high as those of calcined carbide slag.The negative effect of CO_(2) in air as the heat storage fluid on the heat storage capacity of the modified carbide slag is overcome by introducing CO_(2) capture cycles.In addition,the CO_(2) capture reactivity of the modified carbide slag after the multiple calcium looping cycles is enhanced by the introduction of heat storage cycles.By introducing 10 heat storage cycles after the 10th and 15th CO_(2) capture cycles,the CO_(2) capture capacities of the modified carbide slag are subsequently improved by 32%and 43%,respectively.The porous and loose structure of modified carbide slag reduces the diffusion resistances of CO_(2) and steam in the material in the coupled process.The formed CaCO_(3)in the modified carbide slag as a result of air as the heat transfer fluid in heat storage cycles decomposes to regenerate CaO in calcium looping cycles,which improves heat storage capacity.Therefore,the modified carbide slag with by-product of biodiesel seems promising in the coupled calcium looping and CaO/Ca(OH)_(2) heat storage cycles.

CO_(2) gas stripped off membranous residual oil from pore surfaces: Effects of temperature, pressure and wettability

The threshold values of CO_(2) gas stripped off membranous residual oil from the pore walls are not clear under different temperatures, pressures and wettability conditions. The extent to which temperature, pressure and wettability influence CO_(2) flooding for enhancing the recovery of residual oil in membranous formations also remains uncertain. Therefore, further quantitative characterization is entailed. In this study, the molecular dynamics method was employed to explore CO_(2) flooding under different temperatures, pressures and wettability conditions, aiming to enhance the production of membranous residual oil. The results reveal that the interaction energy between CO_(2), decane molecules and pore walls exhibits a decrease with increasing temperature and an increase with increasing pressure, respectively, in distinct wettability scenarios. When the temperature was at or below 363 K and the pressure was not lower than 40 MPa, CO_(2) gas could detach the membranous residual oil from the pore walls in the water-wet systems. When the temperature was equal to 363 K and the pressure remained under 40 MPa, or the temperature surpassed 363 K, CO_(2) gas failed to detach the membranous residual oil from the pore walls in the water-wet systems. For the mixed-wet and oil-wet systems, CO_(2) molecules could not detach the membranous residual oil from the pore walls. The hierarchy of influence regarding temperature, pressure and wettability on the competitive adsorption capacity of CO_(2) and decane molecules on the pore walls emerged as follows: wettability > temperature > pressure. The findings of this study offer valuable insights into the application of CO_(2) gas flooding for the exploitation of membranous residual oil on pore walls.

CO_(2)捕集、利用和封存在能源行业的应用:全球案例分析和启示

为了实现中国21世纪中叶达到碳中和,大规模应用CO_(2)捕获、利用和封存(CCUS)技术可以减少能源行业的温室气体排放。通过对国内外CCUS技术、项目的调研,得出了关于未来CCUS部署的3个见解,这些见解有助于能源行业实现转型。首先,碳源浓度较低导致碳捕集效率低,从而导致碳捕集的经济成本较高的问题是目前CCUS项目无法商业化的主要因素,在发展当前的碳捕集技术,提高捕集效率和降低捕集成本的同时也应大力研究空气捕集技术,尤其是在工艺设计和新型吸附材料研发方面,争取实现弯道超车;其次,CO_(2)在油气藏和咸水层的封存与利用应当作为CCUS技术研究的重点,逐步实现大规模推广,并在技术升级和体系完善的基础上推广CO_(2)增强地热、煤层气等其他耦合技术;最后,应当在当前国际上较成熟的碳政策的基础上研究适合中国的激励政策,建立有效的法律法规。论文总结了当前CCUS的关键挑战,并为未来的CCUS研究方向提供了指导方向。

天然CO_(2)沿井筒泄漏两相反应流动特征模拟

碳捕集利用与封存(CCUS)技术是实现大规模碳减排的重要途径,而CO_(2)注入储层后的泄漏风险是CCUS技术关注的重点之一。由于目前CCUS工程中还未有深部封存的CO_(2)泄漏事故发生,但天然CO_(2)泄漏事件并不少见,因此以天然CO_(2)井筒泄漏点为研究对象进行类比研究可为CCUS工程泄漏风险评估提供有价值的参考依据。以西宁盆地南部天然CO_(2)泄漏场地中的典型CO_(2)井筒泄漏点———ZK10井为研究对象,结合实测数据,采用数值模拟方法分析了该井间歇喷发过程的动力学机制及伴随的化学变化特征。结果表明:①ZK10井的水气间歇喷发过程受CO_(2)过饱和析出、气举效应及储层动态补给的协同控制;②受控于CO_(2)的过饱和析出及流体混合作用,井筒内CO_(2)闪蒸点以上位置地下水的pH值随深度减小而增大,并随喷发过程发生周期性的变化;③ZK10井间歇喷发过程中,井筒内形成方解石和石英矿物沉淀,受控于矿物的溶解特性,其沉淀特征各异。该研究结果可为类似的天然或CCUS工程中CO_(2)井筒泄漏点的泄漏机制及化学特征研究提供参考,进而为相关部门制定监测及预防措施提供依据。

CO_(2)与绿氢合成甲醇的过程模拟及储能性能分析

文章模拟了CO_(2)与绿氢合成甲醇的过程,提出了CO_(2)储能密度指标,研究了多个参数对甲醇储能性能的影响。研究结果表明:系统能效和甲醇能量产率随着电解水效率、单程CO_(2)转化率、电解水压力和CO_(2)初始压力的升高而升高,随着甲醇合成压力的升高而降低;CO_(2)储能密度随以上参数的变化趋势与系统能效和甲醇能量产率相反;电解水效率和单程CO_(2)转化率是敏感关键的参数;在最优组合工况下,基于甲醇高位和低位热值的系统能效分别为68.0%和59.6%,CO_(2)储能密度为6.07 k W·h/kg,能量产率为0.108 kg/(k W·h),表明以CO_(2)为原料的电制甲醇的系统能效不够理想,但储能密度优势显著。

CO_(2)地质利用与封存中碳迁移及其相态分布规律

CO_(2)地质利用与封存技术是“双碳”战略下重要的碳减排手段,前人的研究多集中于地质利用方面,而对地层的碳封存潜力尤其是CO_(2)矿化潜力的定量评价存在不足。为此,通过程序开发手段,将闪蒸计算加入开源的反应溶质运移模拟软件中,利用改进后的软件建立了松辽盆地大情字井油田H59区块的三维地质模型,通过历史拟合注采过程校正模型地层参数,最后采用校正后模型量化表征了不同注入阶段及注采结束后CO_(2)迁移与相态转化的时空演化过程。研究结果表明:①在油藏CO_(2)混相驱条件下,CO_(2)在注入井端的小范围内呈现气相,在接触到油相前缘后,CO_(2)受浮力影响减弱,在垂向上逐渐趋于均匀分布,并向开采井端均匀推进;②气水同注阶段与注气阶段均有超过70%注入的CO_(2)溶解于油相,但气水同注阶段溶解于水相的CO_(2)含量明显增加;③注采结束后的相态演化特征表现为溶解水相CO_(2)逐渐转变为矿物相,而溶解油相CO_(2)存在转变为游离态气相的趋势;④注采结束后,主要矿化过程为绿泥石及铁白云石溶解产生铁、钙离子,与碳酸根离子结合构成方解石和菱铁矿等沉淀矿物(固碳矿物),而主要溶解矿物有钾长石、钙蒙脱石、铁白云石及绿泥石。结论认为,基于现场实测数据,利用嵌入闪蒸计算的CO_(2)地质利用与封存组分模拟软件,提高了对CO_(2)迁移及分布相态规律的进一步认识,研究结果对实现注CO_(2)高效提高采收率与封存具有重要指导意义。

CO_(2)storage with enhanced gas recovery(CSEGR):A review of experimental and numerical studies

CO_(2)emission mitigation is one of the most critical research frontiers.As a promising option of carbon capture,utilization and storage(CCUS),CO_(2)storage with enhanced gas recovery(CSEGR)can reduce CO_(2)emission by sequestrating it into gas reservoirs and simultaneously enhance natural gas production.Over the past decades,the displacement behaviour of CO_(2)—natural gas has been extensively studied and demonstrated to play a key role on both CO_(2)geologic storage and gas recovery performance.This work thoroughly and critically reviews the experimental and numerical simulation studies of CO_(2)displacing natural gas,along with both CSEGR research and demonstration projects at various scales.The physical property difference between CO_(2)and natural gas,especially density and viscosity,lays the foundation of CSEGR.Previous experiments on displacement behaviour and dispersion characteristics of CO_(2)/natural gas revealed the fundamental mixing characteristics in porous media,which is one key factor of gas recovery efficiency and warrants further study.Preliminary numerical simulations demonstrated that it is technically and economically feasible to apply CSEGR in depleted gas reservoirs.However,CO_(2)preferential flow pathways are easy to form(due to reservoir heterogeneity)and thus adversely compromise CSEGR performance.This preferential flow can be slowed down by connate or injected water.Additionally,the optimization of CO_(2)injection strategies is essential for improving gas recovery and CO_(2)storage,which needs further study.The successful K12—B pilot project provides insightful field-scale knowledge and experience,which paves a good foundation for commercial application.More experiments,simulations,research and demonstration projects are needed to facilitate the maturation of the CSEGR technology.

电化学反应性捕集CO_(2)研究进展与挑战

CO_(2)捕集是控制温室气体排放的关键技术之一,电化学CO_(2)还原是关闭人工碳循环的有效途径,但CO_(2)捕集和电化学CO_(2)还原过程均为能源密集型过程。过去的研究将两者视为相互独立的技术和科学领域进行发展。通过直接电解捕集介质(如胺基富液和碳酸氢盐),将上游的碳捕集和下游的电化学还原过程进行集成耦合,可以避免高能耗的捕获介质再生和CO_(2)释放环节,避免CO_(2)的运输和存储操作,降低整体工艺的运行成本,提升整个碳循环的能量效率和经济效益,为节约能源和经济高效地捕集利用CO_(2)提供了一个潜在的解决方案。总结了目前电化学反应性捕集CO_(2)的研究进展,论述了在电极和电解质方面取得的成果,讨论了影响集成电解效率的限制因素,并分析了各类因素的潜在影响机制和可能的反应路径。最后,强调了直接电化学还原捕集介质领域的主要挑战和机遇,并对未来耦合碳捕集与电化学利用过程的发展进行展望。

Carbon dioxide capture, enhanced-oil recovery and storage technology and engineering practice in Jilin Oilfield, NE China

This paper systematically presents the established technologies and field applications with respect to research and engineering practice of CO_(2) capture,enhanced oil recovery(EOR),and storage technology in Jilin Oilfield,NE China,and depicts the available series of supporting technologies across the industry chain.Through simulation calculation+pilot test+field application,the adaptability of the technology for capturing CO_(2) with different concentrations in oilfields was confirmed.The low energy-consumption,activated N-methyl diethanolamine(MDEA)decarburization technology based on a new activator was developed,and the operation mode of CO_(2) gas-phase transportation through trunk pipeline network,supercritical injection at wellhead,and produced gas-liquid separated transportation was established.According to different gas source conditions,liquid,supercritical phase,high-pressure dense phase pressurization technologies and facilities were applied to form the downhole injection processes(e.g.gas-tight tubing and coiled tubing)and supporting anti-corrosion and anti-blocking techniques.In the practice of oil displacement,the oil recovery technologies(e.g.conical water-alternating-gas injection,CO_(2) foam flooding,and high gas-oil ratio CO_(2) flooding)and produced fluid processing technologies were developed.Through numerical simulation and field tests,three kinds of CO_(2) cyclic injection technologies(i.e.direct injection,injection after separation and purification,and hybrid injection)were formed,and a 10×10^(4) m^(3)/d cyclic injection station was constructed to achieve"zero emission"of associated gas.The CO_(2) storage safety monitoring technology of carbon flux,fluid composition and carbon isotopic composition was formed.The whole-process anti-corrosion technology with anticorrosive agents supplemented by anticorrosive materials was established.An integrated demonstration area of CO_(2) capture,flooding and storage with high efficiency and low energy-consumption has been built,with a cumulative oil increment of 32×10^(4) t and a CO_(2) storage volume of 250×10^(4) t.

Advances in subsea carbon dioxide utilization and storage

Decisive steps in innovation and competitiveness are needed to meet global greenhouse gas emissions and climate goals.As an effective method for reducing carbon emissions,carbon dioxide(CO_(2))storage and utilization on the seabed enable the transport of captured CO_(2)via pipelines or ships to permanent storage sites,such as saline aquifers or depleted oil and gas reservoirs in subsea sediments,or by injecting CO_(2)for the replacement and displacement of subsea resources(oil,gas,gas hydrates,etc.).Subsea CO_(2)utilization and storage(SCUS)involves several research hotspots worldwide,including international and local laws and regulations,security,economics,environmental impact,and public acceptance.Its current research and engineering progress are also of great interest.In addition,the vigorous implementation of the energy transition and the rapid development of renewable energy sources globally have resulted in significant advancements in SCUS.This paper provides an overview of carbon dioxide storage and utilization mechanism in the seabed,analyzes key technical and economic issues,and summarizes existing research on safety risks,monitoring technologies,and investment and operating cost control to identify remaining knowledge gaps.This is followed by an overview of global engineering practice to update on current progress.Finally,combined with the actualities of China,the potential and trend of China's seabed carbon storage and utilization are summarized.This review demonstrates the enormous development prospects for seabed carbon storage and utilization,although some risks remain including leakage and contamination,with which innovation in monitoring technologies and the self-sealing effect of gas hydrate,safe subsea utilization and storage of CO_(2)can be achieved.Additionally,considering the development of renewable energy and the demand for large-scale energy storage,hydrogen,ammonia,or other energy carriers and carbon dioxide storage and utilization can be coupled into an industrial chain to form an economically competitive carbon geological storage mode.

Conversion Carbon Capture and Storage Factors in Temperate Human Controlled Wetland

This paper provides guidance for the quantification and reporting of blue carbon removals in the temperate coastal ecosystems,“Italian valli da pesca”or H.C.W.(Human Controlled Wetland,Lat.45°Lon.12°),where some pools as seagrasses,and salt marshes,are highly efficient at capturing and storing carbon dioxide(CO_(2))from the atmosphere.Halophyte salt marsh plants were found to have a%C on Dry Weight(D.W.)of 32.26±3.91(mean±standard deviation),macrophytes 33.65±7.99,seagrasses 29.23±2.23,tamarisk 48.42±2.80,while the first 5 centimetres of wetland mud,on average,had a%C of 8.56±0.94.Like the ISO(International Organization for Standardization)14064 guideline to quantify the GHG(Greenhouse Gas)emission,we have studied the different conversion factors to be used as a practical tool for measurement the CO_(2)sink activity.These factors are essential to calculate the overall carbon reduction in a project located in temperate wetland using a method as the ISO 14064.2,UNI-BNeutral,VCS VERRA or other that will come.

咸水层CO_(2)地质封存典型案例分析及对比

咸水层封存是CO_(2)地质封存方式中潜力最大的。目前全球比较成功的典型咸水层CO_(2)地质封存示范工程有挪威的Sleipner和Snøhvit、阿尔及利亚的In Salah、中国鄂尔多斯盆地神华,这些工程提供了长期CCS的经验,对于未来CO_(2)地质封存项目实施具有借鉴意义。从构造、储层、盖层等地质特征出发,结合各示范工程的注入方案和监测方案将各案例进行了剖析,提取了地质及工程参数,分析了各地质特征对CO_(2)地质封存的影响,明确了背斜、断块、裂缝等不同构造特征CO_(2)地质封存的可行性,对比了咸水层CO_(2)地质封存注入方案和监测方案。Sleipner CO_(2)地质封存项目成功的原因在于构造简单、面积大、储层物性好,盖层厚度大且稳定;Snøhvit发育的断层和In Salah的裂缝也验证了不同构造特征CO_(2)地质封存的可能性,CO_(2)羽流分布受地质特征的控制。咸水层CO_(2)地质封存注入井相对比较少,但是注入量比较大,多以水平井为主。高质量的监测数据可有效降低潜在泄漏风险,多种监测组合有助于CO_(2)长期安全地质封存。

CO_(2)地质封存潜力与能源资源协同的技术基础研究进展

规模化集群化部署是CCUS技术发展方向和化石能源低碳化利用的国家重大需求,CO_(2)地质封存潜力与能源资源协同关系及机制是实现CCUS技术规模化、集群化部署的理论基础。系统梳理评述了国内外CO_(2)地质封存潜力及其评价方法、CCUS源汇匹配与管网设计模型、CO_(2)地质封存潜力与能源资源协同关系、CCUS集群部署技术基础与模式等领域的主要进展,讨论展望了我国CO_(2)地质封存潜力与能源资源协同理论方法体系的研究思路。研究工作取得以下认识:CO_(2)地质封存潜力制约着CCUS技术的发展潜力与应用规模,适宜性评价方法、封存容量评估方法和封存选址方法所构成的CO_(2)地质封存潜力评价方法体系已初步建立,但亟待完善发展;源汇匹配是CO_(2)运输管网设计与CCUS技术集群化部署的重要直接依据,完善建立CCUS源汇匹配规划优化模型与CCUS集群管网设计模型是技术关键,从单阶段静态规划模型向多阶段动态规划模型发展是方向;CO_(2)地质封存潜力与能源资源协同关系构成了CCUS技术的约束条件,CCUS技术与可再生能源、氢能、储能等新能源技术的协同有望形成实现能源系统脱碳的新路径、新模式和新方向,CO_(2)地质封存潜力与生物质、水资源协同关系约束了CCUS技术规模化部署地域和BECCS技术发展应用潜力,基于CCUS源汇匹配模型的能源资源系统优化模型研究也成为新的技术需求;CO_(2)地质封存潜力、能源系统约束的CCUS源汇匹配优化方案和CCUS全流程技术体系构成CCUS集群化部署的重要技术基础,近源输送陆上封存CCUS集群部署模式应是我国优先考虑发展方向,远源输送陆上封存CCUS集群部署模式和离岸封存CCUS集群部署模式在我国长三角、大湾区等区域也有发展前景。

海上CO_(2)地质封存监测现状及建议

海上二氧化碳(CO_(2))地质封存是中国应对滨海地区温室气体排放的重要举措,是实现“碳达峰、碳中和”目标不可或缺的关键技术。中国沿海地区工业发达、碳源丰富,近海盆地具有良好的储盖层物性和圈闭特征,封存潜力巨大,目前中国首个海上CO_(2)地质封存示范工程已在南海珠江口盆地正式启动。CO_(2)监测作为CCUS技术的重要组成部分,贯穿CO_(2)地质封存的全生命周期,是确保封存工程安全性和合理性的必要手段。然而,中国海上CO_(2)地质封存技术处于起步阶段,海上监测任务颇具挑战。文章回顾了国际上海上CO_(2)地质封存的相关代表性研究工作以及示范项目案例,对监测指标、技术、监测方案等进行分析,提出海上CO_(2)地质封存监测技术筛选优化方法和监测建议,旨在为中国海上CO_(2)地质封存示范项目的开展提供参考依据。

CO_(2)混相驱注气速率对重力超覆的影响规律

CO_(2)驱可以改善低渗透油藏的开发效果,并通过置换油气等方式实现CO_(2)地质埋存,但由于油气密度差的存在,会形成CO_(2)重力超覆而影响驱油效果。为明确油层厚度较大的低渗油藏中CO_(2)混相驱条件下注气速率对重力超覆程度的影响规律,分别采用室内物理模拟实验和数值模拟等方法进行研究,并通过建立的数值模型和超覆程度表征方法,系统评价注气速率的影响规律,从而对注入量等参数进行优化。结果表明,混相驱条件下仍存在一定程度的重力分异,且随注气速率的增加,重力超覆程度减弱,混相驱采收率提高,但相比非混相条件,超覆程度较低,通过注气速率优化减弱其影响的效果更为明显。针对给定模型的模拟计算结果表明,当注入量大于10 t/d后超覆程度影响减弱,因此,为保证厚油层CO_(2)混相驱油效果,在不发生气窜的前提下应适当采用较大的注气速率以减弱重力超覆的影响。研究结果对于CO_(2)驱油现场试验方案设计和注气参数优化具有一定的指导意义。