breakthrough pressure
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Energies ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 344
Author(s):  
Ping Yue ◽  
Rujie Zhang ◽  
James J. Sheng ◽  
Gaoming Yu ◽  
Feng Liu

As the demands of tight-oil Enhanced Oil Recovery (EOR) and the controlling of anthropogenic carbon emission have become global challenges, Carbon Capture Utilization and Sequestration (CCUS) has been recognized as an effective solution to resolve both needs. However, the influential factors of carbon dioxide (CO2) geological storage in low permeability reservoirs have not been fully studied. Based on core samples from the Huang-3 area of the Ordos Basin, the feasibility and influential factors of geological CO2 sequestration in the Huang-3 area are analyzed through caprock breakthrough tests and a CO2 storage factor experiment. The results indicate that capillary trapping is the key mechanism of the sealing effect by the caprock. With the increase of caprock permeability, the breakthrough pressure and pressure difference decreased rapidly. A good exponential relationship between caprock breakthrough pressure and permeability can be summarized. The minimum breakthrough pressure of CO2 in the caprock of the Huang-3 area is 22 MPa, and the breakthrough pressure gradient is greater than 100 MPa/m. Huang-3 area is suitable for the geological sequestration of CO2, and the risk of CO2 breakthrough in the caprock is small. At the same storage percentage, the recovery factor of crude oil in larger permeability core is higher, and the storage percentage decreases with the increase of recovery factor. It turned out that a low permeability reservoir is easier to store CO2, and the storage percentage of carbon dioxide in the miscible phase is greater than that in the immiscible phase. This study can provide empirical reference for caprock selection and safety evaluation of CO2 geological storage in low permeability reservoirs within Ordos Basin.


Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Shuren Hao ◽  
Jixiang Cao ◽  
Hua Zhang ◽  
Yulian Liu ◽  
Haian Liang ◽  
...  

The increasing carbon dioxide content is identified as the main cause of global warming. Capturing carbon dioxide in the atmosphere and transporting it to deep salt layer for storage have been proven and practiced in many aspects, which considered to be an effective way to reduce the content of carbon dioxide in the atmosphere. The sealing property of cap rocks is one of the key factors to determine whether CO2 can be effectively stored for a long time. In view of the disadvantages of tedious and time-consuming laboratory test methods for breakthrough pressure of cap rock, this paper explores the relationship between breakthrough pressure and other parameters such as porosity, permeability, density, specific surface area, maximum throat radius, and total organic carbon. The results show that the rock breakthrough pressure is closely related to the maximum throat radius and permeability determined by the mercury injection method, followed by the porosity and specific surface area, and less related to the density, depth, and TOC content of the rock itself. Then, with the selected parameters, a neural network model is established to predict the breakthrough pressure of cap rock, which can achieve good prediction results.


2021 ◽  
pp. 105433
Author(s):  
Jingwei Cui ◽  
Zhongyi Zhang ◽  
Guanglin Liu ◽  
Yan Zhang ◽  
Yalin Qi

SPE Journal ◽  
2020 ◽  
Author(s):  
Xindi Sun ◽  
Baojun Bai ◽  
Ali Khayoon Alhuraishawy ◽  
Daoyi Zhu

Summary With the demand for conformance control in carbon dioxide (CO2) flooding fields, hydrolyzed polyacrylamide-chromium [HPAM-Cr (III)] polymer gel has been applied in fields for CO2 conformance control. However, the field application results are mixed with success and failure. This paper is intended to understand the HPAM-Cr (III) polymer gel plugging performance in CO2 flooding reservoirs through laboratory experiments and numerical analysis. We conducted core flooding tests to understand how the cycles of CO2 and water affect the HPAM-Cr (III) polymer gel plugging efficiency to CO2 and water during a water-alternating-gas (WAG) process. Berea Sandstone cores with the permeability range of 107 to 1225 md were used to evaluate the plugging performance in terms of residual resistance factor and breakthrough pressure, which is the minimum pressure required for CO2 to enter the gel-treated cores.We compared the pressure gradient from the near-wellbore to far-field with the gel breakthrough pressure, from which we analyzed under which conditions the gel treatment could be more successful. Results show that HPAM-Cr (III) polymer gel has higher breakthrough pressure in the low-permeability cores. The polymer gel can reduce the permeability to water much more than that to CO2. The disproportionate permeability reduction performance was more prominent in low-permeability cores than in high-permeability cores. The gel resistance to both CO2 and brine significantly decreased in later cycles. In high-permeability cores, the gel resistance to CO2 became negligible only after two cycles of water and CO2 injection. Because of the significant reduction of pressure gradient from near-wellbore to far-field in a radial flow condition and the dependence of breakthrough pressure on permeability and polymer concentration, we examined hypothetical reservoirs with no fractures, in which impermeable barriers separated high- and low-permeability zones and in which the gel was only placed in the high-permeability zone. We considered two scenarios: CO2 breaking through the gel and no CO2 breakthrough. No breakthrough represents the best condition in which the gel has no direct contact and can be stable in reservoirs for long. In contrast, the breakthrough scenario will result in the gel’s significant degradation and dehydration resulting from CO2 flowing through the gel, which will cause the gel treatment to fail.


2020 ◽  
Vol 81 ◽  
pp. 103408 ◽  
Author(s):  
Tong Wu ◽  
Zhejun Pan ◽  
Luke D. Connell ◽  
Bo Liu ◽  
Xiaofei Fu ◽  
...  

SPE Journal ◽  
2020 ◽  
Vol 25 (04) ◽  
pp. 1745-1760
Author(s):  
Xindi Sun ◽  
Yifu Long ◽  
Baojun Bai ◽  
Mingzhen Wei ◽  
Sujay Suresh

Summary Traditional polyacrylamide (PAM)-based superabsorbent polymer has been applied to control excess carbon dioxide (CO2) production in CO2-flooding fields. Nevertheless, the application results are mixed because the polyacrylamide-based superabsorbent polymer dehydrates significantly when exposed to supercritical CO2; therefore, we evaluated a novel CO2-resistant gel (CRG) with reliable stability and CO2-responsive properties. Particularly, the CRG swelling ratio (SR) and gel-volume increase after CO2 stimulation if additional water is available. Swollen CRG was placed in high-pressure vessels to examine the weight loss and the property changes before and after exposure to CO2. The breakthrough pressure and CRG-plugging efficiency to CO2 were measured using partially open fractured-sandstone cores. Two water/alternating/gas (WAG) cycles were conducted to test the CRG-plugging performance after CRG injection. The high-pressure vessel-test results show that the CRG is very stable under the supercritical-CO2 condition and no free water is released from the samples. The scanning-electron-microscope (SEM) images confirm that no structural damage was observed in CRG after exposure to CO2. The breakthrough pressure increases with the matrix permeability, which is mainly induced by the internal and external gel cake formed on the rock surface. CRG can reduce the water permeability more than CO2 permeability. CRG-plugging efficiency to CO2 decreases with the increase of WAG cycles. However, in the 0.5-mm fracture model and the 390-md model, CRG-plugging efficiency to water increases with WAG cycles. This phenomenon further indicates that CRG can be stimulated by CO2, which allows CRG to absorb additional water during post-waterflooding. In general, this study reports the concept of the novel CRG and a systematical evaluation of CRG stability under supercritical-CO2 conditions and CRG-plugging efficiency using a partially open fractured-sandstone model.


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