Study on distribution characteristics of microscopic residual oil in low permeability reservoirs

Fang, Yujia; Yang, Erlong; Yin, Daiyin; Gan, Yifan

doi:10.1080/01932691.2019.1594886

Cited by 17 publications

(6 citation statements)

References 20 publications

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“…The polymer effect on displacement efficiency due to the viscoelasticity effect is drawing more and more attention [19][20][21][22][23][24][25], while its mechanism explanation is not satisfactory or even contradictory [19]. Some researchers investigate microscopic residual oil remobilization mechanisms [26][27][28][29][30]. However, the claimed displacement improvement due to polymer viscoelasticity and normal stress difference [25,31] is not inconsistent with other researchers' observation [19].…”

Section: Eor Mechanismsmentioning

confidence: 99%

Recent Advances of Surfactant-Polymer (SP) Flooding Enhanced Oil Recovery Field Tests in China

Sun

Guo

et al. 2020

Geofluids

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Recently, there are increasing interests in chemical enhanced oil recovery (EOR) especially surfactant-polymer (SP) flooding. Although alkali-surfactant-polymer (ASP) flooding can make an incremental oil recovery factor (IORF) of 18% original oil in place (OOIP) according to large-scale field tests in Daqing, the complex antiscaling and emulsion breaking technology as well as potential environment influence makes some people turn to alkali-free SP flooding. With the benefit of high IORF in laboratory and no scaling issue to worry, SP flooding is theoretically better than ASP flooding when high quality surfactant is available. Many SP flooding field tests have been conducted in China, where the largest chemical flooding application is reported. 10 typical large-scale SP flooding field tests were critically reviewed to help understand the benefit and challenge of SP flooding in low oil price era. Among these 10 field tests, only one is conducted in Daqing Oilfield, although ASP flooding has entered the commercial application stage since 2014. 2 SP tests are conducted in Shengli Oilfield. Both technical and economic parameters are used to evaluate these tests. 2 of these ten tests are very successful; the others were either technically or economically unsuccessful. Although laboratory tests showed that SP flooding can attain IORF of more than 15%, the average predicted IORF for these 10 field tests was 12% OOIP. Only two SP flooding tests in (SP 1 in Liaohe and SP 7 in Shengli) were reported actual IORF higher than 15% OOIP. The field test in Shengli was so successful that many enlarged field tests and industrial applications were carried out, which finally lead to a commercial application of SP flooding in 2008. However, other SP projects are not documented except two (SP7 and SP8). SP flooding tests in low permeability reservoirs were not successful due to high surfactant adsorption. It seems that SP flooding is not cost competitive as polymer flooding and ASP flooding if judged by utility factor (UF) and EOR cost. Even the most technically and economically successful SP1 has a much higher cost than polymer flooding and ASP flooding, SP flooding is thus not cost competitive as previously expected. The cost of SP flooding can be as high as ASP flooding, which indicates the importance of alkali. How to reduce surfactant adsorption in SP flooding is very important to cost reduction. It is high time to reevaluate the potential and suitable reservoir conditions for SP flooding. The necessity of surfactant to get ultra-low interfacial tension for EOR remains further investigation. This paper provides the petroleum industry with hard-to-get valuable information.

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Section: Eor Mechanismsmentioning

confidence: 99%

Recent Advances of Surfactant-Polymer (SP) Flooding Enhanced Oil Recovery Field Tests in China

Sun

Guo

et al. 2020

Geofluids

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“…The cores were obtained from the Daqing Oilfield; planar heterogeneous photolithographic glass models were made with different permeability ratios of 1, 6, and 9, where permeability ratio is defined as the ratio of the maximum permeability to the minimum permeability of the model. The average permeability of the models is 25 × 10 −3 μm 2 , which is measured by the method of Fang et al [27], and the dimensions are 40 mm × 40 mm. The pore structure photos of a natural core casting thin section were taken with a permeability ratio of 1.…”

Section: Experimental Designmentioning

confidence: 99%

“…Through the video recording system, the distribution characteristics of microscopic residual oil can be photographed in real time. Residual oil can be divided into 5 types according to its cause of formation and distribution in pores including cluster, columnar, oil drop, blind end, and oil film [26,27]. Taking polymeric surfactant flooding as an example, the distribution of residual oil under polymeric surfactant flooding with different permeability ratios can be obtained as shown in Figures 4-6.…”

Section: The Distribution Of Micro Residual Oil After Differentmentioning

confidence: 99%

Study on Distribution Characteristics and Displacement Mechanism of Microscopic Residual Oil in Heterogeneous Low Permeability Reservoirs

2019

Self Cite

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In order to explore the development methods suitable for heterogeneous low permeability reservoirs and study the distribution characteristics of residual oil, photoetched glass and artificial core models with three permeability ratios of 1, 6, and 9 were prepared in this research. Three displacement schemes including polymeric surfactant flooding, polymeric surfactant with binary flooding, and binary flooding were designed at the same expenses to obtain the displacement mechanism of various residual oil saturations. The results show that the best displacement efficiency can be achieved by polymeric surfactant flooding, followed by polymeric surfactant with binary flooding, and binary flooding for the models with the same permeability ratio. Binary flooding mainly activates cluster and oil drop residual oils, polymeric surfactant with binary flooding mainly activates cluster, oil film, and column residual oils, whereas polymeric surfactant flooding mainly activates cluster, oil drop, and column residual oils. In addition, with the increase of the model permeability ratio, the recovery ratio of water flooding decreases, whereas the enhanced oil recovery and the variations in residual oil saturation gradually increase after carrying out different displacement measures. The viscoelastic and shearing effects of the polymeric surfactant flooding system can better displace the residual oil, assisting in the further development of heterogeneous low permeability reservoirs.

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“…At present, research on enriched remaining oil mainly focuses on the distribution characteristics and influencing factors of enriched remaining oil after displacement (Xia et al, 2010, 2021; Tang et al, 2012; Fang et al, 2019; Wang et al, 2020; Zhao, 2021; Jiang et al, 2022), the recovery method of enriched remaining oil (Chen et al, 2013; Liu et al, 2022), and the remaining oil storage mechanism (Dai and Lin, 2020; Song et al, 2020; Wolf et al, 2020). Wang and Ye (2013) studied the distribution law of remaining oil after polymer flooding and proposed five remaining oil enrichment areas after polymer flooding.…”

Section: Introductionmentioning

confidence: 99%

Simulation analysis of the mechanism and influencing factors of remaining oil secondary enrichment in ultra-high water cut fault block reservoirs

Cui

et al. 2023

Energy Exploration & Exploitation

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After the near-abandoned production wells in the high part of the fault block reservoir are closed for a period of time, the remaining oil in the low part will accumulate at the fault in the high part to produce secondary enrichment. At present, research on the secondary enrichment of the remaining oil mainly focuses on the remigration method of the remaining oil, and there is less research on the mechanism of the secondary enrichment of the remaining oil. In view of the above problems, a planar numerical model is established to analyse the remaining oil secondary enrichment law, combined with the longitudinal numerical model to analyse the mechanism of the remaining oil secondary enrichment, and nine factors are selected to study their influence on the remaining oil secondary enrichment law, further determining the main control factors through sensitivity analysis. Based on the numerical simulation results, the reservoir conditions conducive to the secondary enrichment of the remaining oil are determined. The research shows that the remaining oil secondary enrichment mechanism includes pressure redistribution after well shut-in and the comprehensive effect of the micro force. The increase in the formation dip angle, permeability and water injection intensity before well shut-in is beneficial to accelerate the secondary enrichment of the remaining oil. Permeability and formation dip angle are the main controlling factors of positive correlation parameters, and the shut-in water cut is the main controlling factor of negative correlation parameters and the most sensitive. In addition, when the permeability is greater than 200 mD, the formation dip angle is greater than 9°, and the shut-in water cut is less than 95%, which is conducive to the secondary enrichment of the remaining oil. This study has reference significance for the field to understand the mechanism and influencing factors of the secondary enrichment of the remaining oil.

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Study on distribution characteristics of microscopic residual oil in low permeability reservoirs

Cited by 17 publications

References 20 publications

Recent Advances of Surfactant-Polymer (SP) Flooding Enhanced Oil Recovery Field Tests in China

Recent Advances of Surfactant-Polymer (SP) Flooding Enhanced Oil Recovery Field Tests in China

Study on Distribution Characteristics and Displacement Mechanism of Microscopic Residual Oil in Heterogeneous Low Permeability Reservoirs

Simulation analysis of the mechanism and influencing factors of remaining oil secondary enrichment in ultra-high water cut fault block reservoirs

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