Effect of Pore-Throat Microstructures on Formation Damage during Miscible CO<sub>2</sub>Flooding of Tight Sandstone Reservoirs

Wang, Qian; Yang, Shenglai; Glover, Paul; Lorinczi, Piroska; Qian, Kun; Wang, Lu

doi:10.1021/acs.energyfuels.0c00158

Cited by 35 publications

(45 citation statements)

References 57 publications

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“…The pore-throat structure of these four cores was quantitatively evaluated by fractal theory based on the mercury injection capillary pressure (MICP) curve measured by constant-rate mercury injection (CRMI) tests [13] . These tests were carried out using an APSE-730 mercury porosimeter (American Coretest Systems, Inc.) with a quasi-static constant speed of 50 nL/min and a maximum injection pressure of 6.2 MPa).…”

Section: Methodsmentioning

confidence: 99%

“…Moreover, the distributions of pore-throat ratio also imply that H1 and H4 have strong heterogeneity in pore-throat microstructure. [13] . , 15000 mg/dm 3 ), and CO2 were contained separately in four high pressure cylinders (Hongda, China; P=80 MPa; T=130°C).…”

Section: Methodsmentioning

confidence: 99%

“…The effects of all of these factors have been considered with regard to the relative heterogeneity of the pore microstructure. All of the results have been compared to the results of a similar study on the process of continuous miscible CO2 flooding (Wang et al, 2020 ) [13] in order to understand the advantages and disadvantages of each. This comparison was possible because both sets of results were made on the same 4 cores, each of which shared the similar permeability but exhibited a different pore-throat structure and different degrees of heterogeneity of the pore-throat microstructure.…”

Section: Introductionmentioning

confidence: 99%

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Effect of a Pore Throat Microstructure on Miscible CO₂ Soaking Alternating Gas Flooding of Tight Sandstone Reservoirs

Wang

Glover

et al. 2020

Energy Fuels

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Miscible CO2-SAG flooding is an improved version of CO2 flooding, which compensates for the insufficient interaction of CO2 and crude oil in the reservoir by adding a CO2 soaking process after the CO2 breakthrough (BT). The transmission of CO2 in the reservoir during the soaking process is controlled by the pore-throat structure of the formation, which in turn affects the displacement efficiency of the subsequent secondary CO2 flooding. In this work, CO2-SAG flooding experiments at reservoir conditions (up to 70℃, 18 MPa) have been carried out on four samples with very similar permeabilities, but significantly different pore size distributions and pore-throat structures. The results have been compared with the results of CO2 flooding on the same samples. It was found that the oil recovery factors (RFs) when using CO2-SAG flooding are higher than when using CO2 flooding by 8-14%. In addition, we find greater improvements in RF for rocks with greater heterogeneity of their porethroat microstructure compared with CO2 flooding. The CO2 soaking process compensates effectively for the insufficient interaction between CO2 and crude oil due to premature CO2 BT in heterogeneous cores. Moreover, rocks with a more homogeneous pore-throat microstructure exhibit a higher pressure decay rate in the CO2 soaking process. The initial rapid pressure decay stage lasts 80-135 minutes (in our experimental cores), accounting for over 80% of the total decay pressure. Rocks with the larger and more homogeneous pore-throat microstructure exhibit smaller permeability decreases due to asphaltene precipitation after CO2-SAG flooding, possibly because the permeability of rocks with more heterogeneous and smaller pore-throat microstructure is more susceptible to damage from asphaltene precipitation. However, the overall permeability decline is 0.6-3.6% higher than that of normal CO2 flooding due to the increased time for asphaltene precipitation. Nevertheless, the corresponding permeability average decline per 1% oil RF is 0.11-0.34%, which is lower than that for CO2 flooding, making the process worthwhile. We have shown that CO2-SAG flooding has the potential to improve oil RFs with relatively little damage to cores, especially for cores with small and heterogeneous porethroat microstructures, but for which severe wettability changes due to the CO2 soaking process can become significant.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of a Pore Throat Microstructure on Miscible CO₂ Soaking Alternating Gas Flooding of Tight Sandstone Reservoirs

Wang

Glover

et al. 2020

Energy Fuels

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“…However, the reactor is a closed system, which cannot reflect the structural characteristics of porous media. Experiments have also been carried out with artificial cores [28][29][30]. Although there is no water-rock reaction in the artificial tight sandstone core, the pore structure of the artificial low-permeability cores is relatively simple, which cannot simulate the complexity of the pore structure of the tight sandstone cores.…”

Section: Effects Of Comentioning

confidence: 99%

Effect of Fluid/Rock Interactions on Physical Character of Tight Sandstone Reservoirs during CO2 Flooding

Zhao

Yin

2021

Geofluids

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Structures of pore-throat and permeability alteration caused by precipitation and the dissolution of rock matrix are serious problems during CO2 flooding into reservoirs for enhanced oil recovery (EOR). Experiments were conducted under pressure boost and reduction conditions, which simulate CO2-brine scaling in different parts of the reservoir during CO2 flooding. And experiments on the dissolution and scaling of CO2-brine-rock were carried out. The results show that the pH of brine with CO2 under high pressure is small, and no precipitation is formed, so there is no precipitation generated near the gas injection well. Pressure drops sharply near the production well, CO2 dissolved in the formation fluid escapes in large quantities, pH increases, carbonate precipitates are generated, so inorganic scale is formed near the production well. The increase of permeability of core saturated high scale-forming ions is smaller than that of saturated no scale-forming ions brine after CO2 flooding. The accumulation and attachment of salt crystals were found in some large pores of the core with scale-forming ions water after CO2 flooding. The ratio of medium size pores decreased, while that of large and small pores increases, and the pore radius distribution differentiates toward polarization.

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“…Since the 1960s, numerous scholars mainly studied the flow characteristic of the fluid in naturally fractured reservoirs by the method of the pressure transient analysis (Warren and Root, 1963;Pruess and Narasimhan, 1985;Kuchuk and Biryukov, 2014;Kui et al, 2017;Tan et al, 2018;Yin, 2018;Song et al, 2019;Pang et al, 2020;Tontiwachwuthikul et al, 2020;Wang et al, 2020). Since a large number of the fractured-vuggy carbonate hydrocarbon reservoirs (FVCHRs) were found around the world, most of scholars have focused on studies of FVCHRs to understand flow characteristic of the fluid in the FVCHRs (Abadassah and Ershaghi, 1986;Liu et al, 2003;Sun et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Transient Pressure Analysis of Inclined Well in Continuous Triple-Porosity Reservoirs With Dual-Permeability Behavior

Tan

et al. 2020

Front. Energy Res.

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Inclined wells has recently been adopted to develop fractured-vuggy carbonate hydrocarbon reservoirs (FVCHRs) composed by matrix, fracture and vug system. Therefore, it is significant for us to describe pressure transient of inclined well for FVCHRs. In this paper, it is assumed that vug and fracture system connect with wellbore, and inter-porosity flow from vug to fracture system appears. Therefore, the pressure transient responses model of inclined well with triple-porosity dual-permeability behavior was built. The model is solved by employing Laplace integral transform and finite cosine Fourier transform. Real-domain solution of the model is obtained by Stehfest inversion algorithm. On the basis model of the published paper, the solution of the simplified model of this paper was validated with horizontal and vertical well of FVCHRs with triple-porosity dual-permeability behavior, and results reach a good agreement. Type curve, according to pressure derivative curve characteristic, can be divided into eight flow regimes, which includes wellbore storage, skin reflect, early vertical radial flow, top and bottom boundary reflection, linear flow, inter-porosity flow from vug to fracture, inter-porosity from matrix to vug and fracture and pseudo-radial flow regimes. The influence of some vital parameters (inclination angle, inter-porosity flow coefficient, well length and permeability ratio etc.) on dimensionless pressure and its derivative curves are discussed in detail. The presented model can be used to understand pressure transient response characteristic of inclined wells in FVCHRs with dual-permeability behavior.

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Effect of Pore-Throat Microstructures on Formation Damage during Miscible CO₂Flooding of Tight Sandstone Reservoirs

Cited by 35 publications

References 57 publications

Effect of a Pore Throat Microstructure on Miscible CO₂ Soaking Alternating Gas Flooding of Tight Sandstone Reservoirs

Effect of a Pore Throat Microstructure on Miscible CO₂ Soaking Alternating Gas Flooding of Tight Sandstone Reservoirs

Effect of Fluid/Rock Interactions on Physical Character of Tight Sandstone Reservoirs during CO2 Flooding

Transient Pressure Analysis of Inclined Well in Continuous Triple-Porosity Reservoirs With Dual-Permeability Behavior

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Effect of Pore-Throat Microstructures on Formation Damage during Miscible CO2Flooding of Tight Sandstone Reservoirs

Cited by 35 publications

References 57 publications

Effect of a Pore Throat Microstructure on Miscible CO2 Soaking Alternating Gas Flooding of Tight Sandstone Reservoirs

Effect of a Pore Throat Microstructure on Miscible CO2 Soaking Alternating Gas Flooding of Tight Sandstone Reservoirs

Effect of Fluid/Rock Interactions on Physical Character of Tight Sandstone Reservoirs during CO2 Flooding

Transient Pressure Analysis of Inclined Well in Continuous Triple-Porosity Reservoirs With Dual-Permeability Behavior

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Effect of Pore-Throat Microstructures on Formation Damage during Miscible CO₂Flooding of Tight Sandstone Reservoirs

Effect of a Pore Throat Microstructure on Miscible CO₂ Soaking Alternating Gas Flooding of Tight Sandstone Reservoirs

Effect of a Pore Throat Microstructure on Miscible CO₂ Soaking Alternating Gas Flooding of Tight Sandstone Reservoirs