“eating carbon” and “spitting oil”: visiting ccus in shengli oilfield
2024-09-15
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students from the national college students journalism practice camp are learning about the ccus project on site. photo by yu chengyan
"injecting carbon dioxide into underground oil reservoirs can effectively improve the fluidity of crude oil, thereby increasing oil production. moreover, carbon dioxide can be permanently retained underground to achieve carbon reduction and carbon fixation." zhang dong, manager of the gas drive laboratory at sinopec shengli oilfield exploration and development research institute, said that compared with previous water drives, using carbon dioxide to drive oil is more efficient and less costly.
the scientific name of this oil recovery technology is carbon dioxide capture, utilization and storage (ccus) technology. it refers to the collection of carbon dioxide produced by emission sources such as fertilizer plants, power plants, steel mills, cement plants, and smelters, and then transporting it to designated places through pipelines and other means, separating, compressing, and utilizing the carbon dioxide. it is an emerging technology for low-carbon and efficient development of fossil energy.
carbon emissions used to be the biggest headache for the oil industry, but now they have become a hot topic to promote oil production and green and low-carbon energy transformation.
"this is a gas storage tank dedicated to our ccus project, which can store 100 tons of carbon dioxide." according to liu tong, a staff member of the shengli oilfield steam injection technical service center, the shengli oilfield lai 113 block carbon dioxide station 1 is one of the gas injection stations in my country's first million-ton ccus project - the "qilu petrochemical-shengli oilfield million-ton ccus project."
it is understood that sinopec relies on its upstream and downstream integration advantages, utilizes the high-quality, low-cost carbon dioxide resources of its refining and chemical companies, and combines them with the existing blocks of its oilfield companies to open up the entire industrial chain of carbon dioxide capture, utilization, and storage, thus realizing a closed loop from carbon dioxide extraction to use.
according to zhang yong, party secretary of the carbon dioxide project department of the steam injection technology service center of block 113 of laiwu, the carbon dioxide here mainly comes from the second fertilizer plant of qilu petrochemical in zibo city, and the carbon dioxide tail gas emitted by its coal gasification unit has stable performance and a purity of up to 95%. a popular science display board in the control room of block 113 of laiwu introduced that the "carbon consumption" ability of ccus technology is "equivalent to planting nearly 9 million trees and stopping the operation of nearly 600,000 economy cars for one year."
for the land of lai 113 block, carbon dioxide can be drilled into the ground here to "cover the quilt". the so-called "covering the quilt" refers to the injection of liquid carbon dioxide into underground rock formations in a pressurized manner. because the underground oil reservoirs are dense and have few gaps, it is difficult for carbon dioxide to escape after entering the rock formation, just like covering it with a thick quilt, so that greenhouse gas emissions can be reduced. in addition, this technology can also increase the fluidity and recovery rate of crude oil by increasing formation pressure. so the technology of ccus can be summarized in one sentence that it can both "eat carbon" and "spit out oil." the most important thing is that this technology will recycle the carbon dioxide vaporized during the injection process into the storage tank to ensure net zero emissions during the injection process, and achieve true carbon reduction, oil increase, and green development.
li xuesong, an expert at the ccus laboratory of the exploration and development research institute, said that if we want to fully achieve the goal of "eating carbon", "oil displacement" alone is not enough. carbon sequestration is also a very important part of ccus, that is, to seal carbon dioxide underground. li xuesong explained that there are three ways for carbon dioxide to enter the ground: displacement, dissolution and mineralization. these three ways can make carbon dioxide be sealed underground.
so far, including lai 113 block, shengli oilfield has applied ccus technology in 13 blocks, injecting and storing more than 1.5 million tons of carbon dioxide, and increasing the average single well production by 36.8%. it reduces carbon dioxide emissions by about 1 million tons per year. after the project is completed, it is expected that more than 10 million tons will be injected in 15 years, increasing oil production by nearly 3 million tons, and increasing the recovery rate by more than 12 percentage points.
the achievement of these results is inseparable from the technical research and technological innovation of several generations of scientific researchers in shengli oilfield.
"underground oil does not flow freely like a river. some low-permeability reservoirs are stored in rock cracks thousands of meters underground, making them difficult to exploit." cheng ziyan, manager of the reservoir evaluation research office of shengli oilfield exploration and development research institute, said that low-permeability reservoirs are a "hard bone" that must be gnawed in oilfield development, and are of great significance to securing energy security. cheng ziyan introduced that supercritical carbon dioxide has a small molecular structure and low viscosity, making it easier to enter the pores of low-permeability rocks, allowing the crude oil originally hidden in the pores to "appear."
theoretically, co2 flooding is effective, but in practice, it is difficult to overcome each hurdle. shengli oilfield researchers started to tackle this problem in 1967. after several generations of efforts, they finally achieved the goal of “no oil on the ground, no water discharged, and no gas going up into the sky”.
it is understood that sinopec will study the establishment of a carbon capture, utilization and storage technology research and development center, focus on the deployment of cutting-edge and reserve technology research and development such as ccus+wind and solar power, ccus+hydrogen energy, ccus+biomass energy, and build a "technology development-engineering demonstration-industrialization" carbon dioxide utilization technology innovation system, extend the clean carbon fixation industry chain, create a source of carbon emission reduction technology innovation, promote the industrialization development of ccus, and open up broader prospects for my country to achieve its "dual carbon" goals.
zhang rang, nie zizhuo, huang ao, li ming, xia lei, xiangyao, zhang chenhao source: china youth daily
(source: china youth daily)
