Quantitative study on the blockage degree of pores due to asphaltene precipitation in low-permeability reservoirs with NMR technique

Wang, Chen; Li, Tiantai; Gao, Hui; Zhao, Jinsheng; Gao, Yuan

doi:10.1016/j.petrol.2017.11.021

Cited by 28 publications

(34 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When the pressure reaches a certain value in the CO2 injection process, changes in composition of the crude oil due to the dissolved CO2 lead to asphaltene precipitation. The asphaltene solid particles are captured or adsorbed on the pores' walls, resulting in blocked pores and pore throats [25][26][27][28] . Moreover, variations of ion concentration and the pH of the brine caused by CO2-brine-rock interactions lead to precipitation of metal carbonates.…”

Section: Introductionmentioning

confidence: 99%

“…However, the mutual relationship between oil recovery, residual oil and permeability decline has rarely been studied in multilayer reservoirs for different flooding methods. The combined effect and difference between asphaltene precipitation and CO2-brine-rock interactions on damage to pore structure have been ignored in most past studies [26,28,[38][39][40][41][42] . Unfortunately rock cores cannot be reused in multiple experiments under different conditions due to irreversible changes caused predominantly by CO2brine-rock interactions in rocks during flooding processes [43][44] .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Experimental Investigation of Oil Recovery Performance and Permeability Damage in Multilayer Reservoirs after CO₂ and Water–Alternating-CO₂ (CO₂–WAG) Flooding at Miscible Pressures

et al. 2019

View full text Add to dashboard Cite

Blockage in reservoirs caused by asphaltene deposits and inorganic interactions is a serious problem that may exacerbate the complexity of displacement characteristics in heterogeneous multilayer sandstone reservoirs and affect crude oil recovery performance during CO2 and CO2-WAG flooding. In this study, experiments of both CO2 and CO2-WAG flooding were carried out on the same multilayer systems under miscible conditions (70℃, 18 MPa). The two flooding methods were evaluated for oil production performance and reservoir damage. The experimental results indicate that, after CO2 flooding, the entire system has a low oil recovery factor (RF) of 27.6%, and oil is produced mainly from the high permeability layer (91.4%), whilst the residual oil remains predominantly in the medium and low permeability layers. The injection pressure of CO2-WAG flooding is high, but the timing of CO2 breakthrough (BT) is late, and the oil RF of the entire system reaches 44.5%. The contribution rate of oil production in medium and low permeability layers is improved to 3.8% and 17.1%, respectively. Furthermore, the permeability of the high permeability layer decreases by 16.8% after CO2 flooding, which is mainly due to asphaltene precipitation. However, after CO2-WAG flooding, the permeability of each layer is significantly reduced, namely by 29.4%, 16.8% and 6.9% respectively. Asphaltene precipitation is still the main factor, but permeability decline caused by CO2-brine-rock interactions cannot be ignored, especially in the high permeability layer (6.1%). Therefore, for multilayer reservoirs with high heterogeneity, CO2-WAG flooding provides the better oil displacement performance, but prevention and control measures for asphaltene precipitation are more necessary.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Oil Recovery Performance and Permeability Damage in Multilayer Reservoirs after CO₂ and Water–Alternating-CO₂ (CO₂–WAG) Flooding at Miscible Pressures

et al. 2019

View full text Add to dashboard Cite

show abstract

“…This is the theoretical basis for studying the pore structure and fluid distribution by NMR spectrum (T 2 spectrum). 28,29 The total relaxation time mainly depends on the relaxation time of the rock surface in tight sandstone. Surface relaxation is related to the surface area of the rock.…”

Section: Methodsmentioning

confidence: 99%

Influence of Pressure on Spontaneous Imbibition in Tight Sandstone Reservoirs

Wang

Gao

et al. 2020

Energy Fuels

Self Cite

View full text Add to dashboard Cite

Reservoir pressure is a key factor affecting the degree of spontaneous imbibition. In this work, the oil distribution characteristics in core samples were simulated before and after spontaneous imbibition using nuclear magnetic resonance (NMR) technology. Specifically, four core samples were selected and subjected to spontaneous imbibition experiments at 0.1, 5, 10, and 15 MPa, respectively. Furthermore, the imbibition efficiency and imbibition rate at different pressures can be quantitatively calculated using the NMR T 2 spectrum. The results indicate that the imbibition efficiency of smaller and larger pores has no obvious trend in the initial stage of spontaneous imbibition (0−72 h). After 72 h of spontaneous imbibition, there was a significant positive correlation between the imbibition efficiency and experimental pressure. Moreover, the imbibition rate of smaller pores increased monotonically with the increase in experimental pressure at 72−216 h in the four core samples. The imbibition rate of the smaller pores in core sample #4 at an experimental pressure of 15 MPa reached a maximum of 0.245%/h. However, the imbibition rate of larger pores in the four core samples has no significant correlation with pressure. In the overall analysis, the imbibition efficiency and imbibition rate of the four core samples have a positive correlation with the experimental pressure. At the same time, it was found that because of the greater number of smaller pores in tight sandstone, the degree of influence of experimental pressure on the spontaneous imbibition effect in smaller pores determines its influence on the overall spontaneous imbibition in the tight sandstone reservoir.

show abstract

“…Extensive core-flooding experiments have been conducted in order to investigate permeability decline and wettability alteration caused by asphaltene precipitation during CO2 flooding processes [32][33][34] , including the effects of permeability, displacement pressure, displacement methods, crude oil properties and other factors on asphaltene precipitation and reservoir damage [35][36][37][38][39] . In addition, the distributions of blockage by asphaltene precipitation in the pores and throats of sandstone have been evaluated quantitatively using nuclear magnetic resonance (NMR) measurements [14,40] . Nevertheless, the effects of the rock pore-throat structure on the damage to pore-throat structure itself during asphaltene precipitation have been rarely studied directly [35,41] .…”

Section: Introductionmentioning

confidence: 99%

“…Unfortunately, these prerequisites have not been satisfied in most core-flooding experiments [32,42] . In addition, while the distributions of pore-throat blockage have been studied qualitatively through the distributions of oil and water re-saturation after flooding in previous studies, the influences of wettability alteration have been ignored [14,40] .…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2020

View full text Add to dashboard Cite

including the URL of the record and the reason for the withdrawal request.This document is confidential and is proprietary to the American Chemical Society and its authors. Do not copy or disclose without written permission. If you have received this item in error, notify the sender and delete all copies.Effect of pore-throat microstructures on formation damage in tight sandstone reservoirs during miscible CO2 flooding

show abstract

Quantitative study on the blockage degree of pores due to asphaltene precipitation in low-permeability reservoirs with NMR technique

Cited by 28 publications

References 16 publications

Experimental Investigation of Oil Recovery Performance and Permeability Damage in Multilayer Reservoirs after CO₂ and Water–Alternating-CO₂ (CO₂–WAG) Flooding at Miscible Pressures

Experimental Investigation of Oil Recovery Performance and Permeability Damage in Multilayer Reservoirs after CO₂ and Water–Alternating-CO₂ (CO₂–WAG) Flooding at Miscible Pressures

Influence of Pressure on Spontaneous Imbibition in Tight Sandstone Reservoirs

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

Contact Info

Product

Resources

About

Quantitative study on the blockage degree of pores due to asphaltene precipitation in low-permeability reservoirs with NMR technique

Cited by 28 publications

References 16 publications

Experimental Investigation of Oil Recovery Performance and Permeability Damage in Multilayer Reservoirs after CO2 and Water–Alternating-CO2 (CO2–WAG) Flooding at Miscible Pressures

Experimental Investigation of Oil Recovery Performance and Permeability Damage in Multilayer Reservoirs after CO2 and Water–Alternating-CO2 (CO2–WAG) Flooding at Miscible Pressures

Influence of Pressure on Spontaneous Imbibition in Tight Sandstone Reservoirs

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

Contact Info

Product

Resources

About

Experimental Investigation of Oil Recovery Performance and Permeability Damage in Multilayer Reservoirs after CO₂ and Water–Alternating-CO₂ (CO₂–WAG) Flooding at Miscible Pressures

Experimental Investigation of Oil Recovery Performance and Permeability Damage in Multilayer Reservoirs after CO₂ and Water–Alternating-CO₂ (CO₂–WAG) Flooding at Miscible Pressures

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