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

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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Alkali Effect on Alkali-Surfactant-Polymer (ASP) Flooding Enhanced Oil Recovery Performance: Two Large-Scale Field Tests’ Evidence

Journal of Chemistry ◽

10.1155/2020/2829565 ◽

2020 ◽

Vol 2020 ◽

pp. 1-22 ◽

Cited By ~ 3

Author(s):

Chen Sun ◽

Hu Guo ◽

Yiqiang Li ◽

Guipu Jiang ◽

Ruicheng Ma

Keyword(s):

Enhanced Oil Recovery ◽

Field Test ◽

Oil Recovery ◽

Large Scale ◽

Field Tests ◽

Oil Prices ◽

Asp Flooding ◽

Scale Field ◽

Large Scale Field ◽

Better Than

Alkali-surfactant-polymer (ASP) flooding is very promising chemical enhanced oil recovery (EOR) technology which can make an incremental oil recovery factor (IORF) of 30% original oil in place (OOIP). How to choose alkali in ASP flooding remains a question for a long time. As the world’s only and largest ASP flooding application place, Daqing Oilfield has always adhered to the strategy of parallel development of strong alkali ASP flooding (SASP) and weak alkali ASP flooding (WASP), but SASP is in a dominant position, indicated by more investments and more project numbers. This leaves an impression that SASP is better than WASP. However, WASP is drawing more interest than SASP recently. Moreover, as the ASP flooding in Daqing went from field tests to commercial applications since 2014, how to comprehensively consider the benefit and cost of ASP flooding has become a new focus at low oil prices. This paper compares two typical large-scale field tests (B-1-D SASP and B-2-X WASP) completed in Daqing Oilfield and analyzes and discusses the causes of this difference. The injection viscosity and interfacial tension (IFT) for the two field test areas are substantially equivalent under the conditions of Daqing Oilfield, and WASP is better than SASP when reservoir geological conditions are considered. WASP exhibits the same IORF of 30% as SASP while having a much better economic performance. For the SASP field test, the injected strong alkali NaOH makes the test behave unlike a typical strong ASP flooding due to the presence of CO2 in the formation fluid, which well explains why IORF is much higher than all the other SASPs but scaling is less severe than others. This paper confirms that under Daqing Oilfield reservoir conditions, it is the alkali difference that caused the performance difference of these two tests, although some minor uncertainties exist. WASP is better than the SASP providing the same conditions . In addition, the detailed information of the two ASP field tests provided can give reference for the implementation of ASP flooding in other oilfields. After all, the study of ASP flooding enhanced oil recovery technology under low oil prices requires great foresight and determination.

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A Numerical Simulation Comparison of Five-Spot vs. Line Drive in Micellar/Polymer Flooding

Society of Petroleum Engineers Journal ◽

10.2118/9427-pa ◽

1982 ◽

Vol 22 (01) ◽

pp. 69-78

Author(s):

H. Kazemi ◽

D.J. MacMillan

Keyword(s):

Enhanced Oil Recovery ◽

Oil Recovery ◽

Large Scale ◽

Plug Flow ◽

Recovery Process ◽

Field Application ◽

Polymer Flooding ◽

Spot Pattern ◽

Injection Wells ◽

Production Wells

Abstract The work presented in this paper was undertaken to study the effect of pattern configuration on oil recovery by the Maraflood oil-recovery process. The patterns studied are the five-spot and the 4 × 1 line drive. These patterns are obtained by placing infill wells in an existing 10-acre (40 469-m2) waterflooded five-spot pattern to obtain the 2.5-acre (10 117-m2) patterns. The number of infill wells is the same for both the new five-spot and new line-drive configurations and is about three times the number of existing wells. Both patterns have been used successfully in field applications by Marathon before this study. For instance, a line-drive pattern was used in Project 119-R and a five-spot pattern was used in Project 219-R. This work shows that the line drive produces more tertiary oil than the five-spot under otherwise identical reservoir conditions. Breakthrough times and oil rates for line-drive production wells are nearly the same. Meanwhile, five-spot production wells have vastly differing oil breakthrough times and oil rates. Both of the latter effects result from a nonuniform distribution of waterflood residual oil saturation in the field. Our study also shows that if producing wells in each line-drive row are connected by a perfect vertical fracture and if the same is true of the injection wells, the line-drive efficiency will improve very little. Introduction The Maraflood oil-recovery process is a viable enhanced oil-recovery technique. An appraisal of this process and other surfactant-enhanced oil-recovery schemes was reported by Gogarty. Three significant field tests of the Maraflood process were reported by Earlougher et al. In addition, a large-scale field application of this process was presented recently by Howell et al. in field applications of the Maraflood process, both line-drive and five-spot configurations have been used. In our field experience, an existing five-spot waterflood pattern is convened to another five-spot or 4 × 1 line-drive configuration by adding infill wells. The new five-spot or line-drive pattern has an area-per-well spacing of one-fourth of the original waterflood spacing. In practice, the number of infill wells required for both cases is somewhat greater than three times the number of existing wells. As the total number of wells increases, this ratio approaches the theoretical limit of three. In addition to the preceding arrangements of infill wells, many others are possible. In some arrangements, fewer infill wells are required than in our five-spot and 4 × 1 line drive. In such cases, the area per well increases, which generally causes these problems:required injectivity per injection well increases and may not be attainable because of the high viscosity of the injected fluids andthe breakthrough time is delayed. As an example, consider the case where no infill wells are drilled. In addition to the two problems just listed, the micellar/polymer flooding scheme will sweep only those regions that already have been swept well by the waterflood. The regions left unswept by the waterflood also will be left essentially unswept by the micellar/polymer flood. This means that a substantial amount of oil is left in place. Therefore, these types of undesired patterns were not considered in this study. Patterns with more infill wells than those in this study were not considered because of current economic limitations. Because of the likelihood of economic and technical merits, we also considered the placement of long vertical fractures to connect existing waterflood wells in place of infill wells. The fractures were arranged to form a more effective line drive. We emphasize that the patterns studied in this paper are those usually used in micellar/polymer flooding applications. Muskat has reported breakthrough waterflood sweep efficiencies of 72% and 88% for five-spot and 4 × 1 line drive patterns when the mobility ratio is unity. Muskat's results are for ideal plug flow displacement of red water by blue water in a perfectly homogeneous reservoir. SPEJ P. 69^

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Cation Exchange Capacity in Mirador and Misoa Formation and the Effect in Enhanced Oil Recovery

Revista Fuentes El Reventón Energético ◽

10.18273/revfue.v18n1-2020004 ◽

2020 ◽

Vol 18 (1) ◽

pp. 31-40

Author(s):

Victoria Mousalli ◽

Johnny Bullón ◽

Franklin Franklin

Keyword(s):

Porous Media ◽

Cation Exchange ◽

Enhanced Oil Recovery ◽

Oil Recovery ◽

Cation Exchange Capacity ◽

Petroleum Industry ◽

Exchange Capacity ◽

Economic Feasibility ◽

Surfactant Adsorption ◽

Adsorption Mechanisms

In the Enhanced Oil Recovery (EOR) methods, particularly in surfactant flooding, many tests have been performed, many scientific papers have been written and many findings have been found; however, there are still a lot of questions without any answers. Some of them are the interactions between the different reservoir components and the chemical flooding that are used in the EOR process. Nowadays, the main problem in the petroleum industry is the economic feasibility. Some authors report that the surfactant lost by the adsorption in the porous media increases the amount of surfactant that is needed. Understanding and controlling the amount of surfactant adsorbed directly, affects the project economics. It is crucial to the economic success of an EOR project that adsorption is reduced in the project design; to do so it requires an understanding of surfactant adsorption mechanisms. One of the factors that affect the surfactant adsorption in porous media is the mineralogy of the reservoir by the Cation Exchange Capacity (CEC) due to clays minerals present in the mineral composition of the reservoir.

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Frontier Enhanced Oil Recovery (EOR) Research on the Application of Imbibition Techniques in High-Pressure Forced Soaking of Hydraulically Fractured Shale Oil Reservoirs

Geofluids ◽

10.1155/2021/6634357 ◽

2021 ◽

Vol 2021 ◽

pp. 1-17

Author(s):

Guanqun Li ◽

Yuliang Su ◽

Yingchun Guo ◽

Yongmao Hao ◽

Lei Li

Keyword(s):

High Pressure ◽

Crude Oil ◽

Enhanced Oil Recovery ◽

Oil Recovery ◽

Large Scale ◽

Fluid Transport ◽

Field Tests ◽

Shale Oil ◽

Oil Composition ◽

Fracturing Fluid

Shale reservoirs are characterized by low porosity and low permeability, and volume fracturing of horizontal wells is a key technology for the benefits development of shale oil resources. The results from laboratory and field tests show that the backflow rate of fracturing fluid is less than 50%, and the storage amount of fracturing fluid after large-scale hydraulic fracturing is positively correlated with the output of single well. The recovery of crude oil is greatly improved by means of shut-in and imbibition, therefore attracting increasing attention from researchers. In this review, we summarize the recent advances in the migration mechanisms and stimulation mechanisms of horizontal well high pressure forced soaking technology in the reservoirs. However, due to the diversity of shale mineral composition and the complexity of crude oil composition, the stimulation mechanism and effect of this technology are not clear in shale reservoir. Therefore, the mechanism of enhanced oil recovery by imbibition and the movable lower limit of imbibition cannot be characterized quantitatively. It is necessary to solve fragmentation research in the full-period fluid transport mechanisms in the follow-up research.

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Recent Advance of Microbial Enhanced Oil Recovery (MEOR) in China

Geofluids ◽

10.1155/2019/1871392 ◽

2019 ◽

Vol 2019 ◽

pp. 1-16 ◽

Cited By ~ 10

Author(s):

Haicheng She ◽

Debin Kong ◽

Yiqiang Li ◽

Zaiqiang Hu ◽

Hu Guo

Keyword(s):

Enhanced Oil Recovery ◽

Oil Recovery ◽

Molecular Level ◽

Field Tests ◽

Commercial Application ◽

Fluid Temperature ◽

High Resolution Mass Spectrum ◽

Microbial Enhanced Oil Recovery ◽

Indigenous Microorganism ◽

Microbial Flooding

Compared with other enhanced oil recovery (EOR) techniques like gas flooding, chemical flooding, and thermal production, the prominent advantages of microbial enhanced oil recovery (MEOR) include environment-friendliness and lowest cost. Recent progress of MEOR in laboratory studies and microbial flooding recovery (MFR) field tests in China are reviewed. High biotechnology is being used to investigate MFR mechanisms on the molecular level. Emulsification and wettability alternation due to microbial effects are the main interests at present. Application of a high-resolution mass spectrum (HRMS) on MEOR mechanism has revealed the change of polar compound structures before and after oil degradation by the microbial on the molecular level. MEOR could be divided into indigenous microorganism and exogenous microorganism flooding. The key of exogenous microorganism flooding was to develop effective production strains, and difficulty lies in the compatibility of the microorganism, performance degradation, and high cost. Indigenous microorganism flooding has good adaptation but no follow-up process on production strain development; thus, it represents the main development direction of MEOR in China. More than 4600 wells have been conducted for MEOR field tests in China, and about 500 wells are involved in MFR. 47 MFR field tests have been carried out in China, and 12 field tests are conducted in Daqing Oilfield. MFR field test’s incremental oil recovery is as high as 4.95% OOIP, with a typical slug size less than 0.1 PV. The input-output ratio can be 1 : 6. All field tests have shown positive results in oil production increase and water cut reduction. MEOR screening criteria for reservoirs in China need to be improved. Reservoir fluid, temperature, and salinity were the most important three parameters. Microbial flooding technology is mature in reservoirs with temperature lower than 80°C, salinity less than 100,000 ppm, and permeability above 5 mD. MFR in China is very close to commercial application, while MFR as quaternary recovery like those in post-polymer flooding reservoirs needs further study.

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