Recent Progress and Effects Analysis of Foam Flooding Field Tests in China

Zhu, Youyi; Hou, Qingfeng; Weng, Rui; Jian, Guoqing; Luo, Yousong; Li, Jianguo

doi:10.2118/165211-ms

Cited by 20 publications

(8 citation statements)

References 1 publication

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“…Foam increases sweep efficiency during gas injection in enhanced oil recovery applications (Holm 1968;Schramm 1994;Patzek 1996;Skauge et al 2002;Blaker et al 2002;Zhu et al 2013;Lake et al 2014). It is also used in aquifer remediation and in acid diversion in well-stimulation treatments (Thompson and Gdanski 1993;Behenna 1995;Hirasaki et al 1997a, b;Talabani et al 2001;Cheng et al 2002;Maire et al 2015;Portois et al 2018).…”

Section: Foam In Porous Mediamentioning

confidence: 99%

Fractional-Flow Theory for Non-Newtonian Surfactant-Alternating-Gas Foam Processes

et al. 2019

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Foam can improve sweep efficiency in gas-injection-enhanced oil recovery. Surfactantalternating-gas (SAG) is a favored method of foam injection. Laboratory data indicate that foam can be non-Newtonian at low water fractional flow f w , and therefore during gas injection in a SAG process. We investigate the implications of this finding for mobility control and injectivity, by extending fractional-flow theory to gas injection in a non-Newtonian SAG process in radial flow. We make most of the standard assumptions of fractional-flow theory (incompressible phases, one-dimensional displacement through a homogeneous reservoir, instantaneous attainment of local equilibrium), excluding Newtonian mobilities. For this initial study, we ignore the effect of changing or non-uniform oil saturation on foam. Non-Newtonian behavior at low f w implies that the limiting water saturation for foam stability varies as superficial velocity decreases with radial distance from the well. We discretize the domain radially and perform Buckley-Leverett analysis on each narrow increment in radius. Solution characteristics move outward with fixed f w. We base the foam model parameters and non-Newtonian behavior on laboratory data in the absence of oil. We compare results to mobility and injectivity determined by conventional simulation, where grid resolution is usually limited. For shear-thinning foam, mobility control improves as the foam front propagates from the well, but injectivity declines somewhat with time. This change in mobility ratio is not that at steady state at fixed water fractional flow in the laboratory, however, because the shock front in a non-Newtonian SAG process does not propagate at fixed fractional flow (though individual characteristics do). Moreover, the shock front is not governed by the conventional condition of tangency to the fractionalflow curve, though it continually approaches this condition. Injectivity benefits from the increased mobility of shear-thinning foam near the well. The foam front, which maintains a constant dimensionless velocity for Newtonian foam, decelerates somewhat with time for shear-thinning foam. For shear-thickening foam, mobility control deteriorates as the foam front advances, though injectivity improves somewhat with time. Overall, however, injectivity suffers from reduced foam mobility at high superficial velocity near the well. The foam front accelerates somewhat with time. Conventional simulators cannot adequately represent these effects, or estimate injectivity accurately, in the absence of extraordinarily fine grid resolution near the injection well.

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Section: Foam In Porous Mediamentioning

confidence: 99%

Fractional-Flow Theory for Non-Newtonian Surfactant-Alternating-Gas Foam Processes

et al. 2019

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“…Among them, four production Wells originally used for first polymer flooding wells locate in the main streamline of polymer flooding well pattern and the water cut rises from 92.6% before the field test to 95.7%, another 12 wells originally used for water flooding wells locate in the distributary streamline of polymer flooding well pattern and the water cut of four central wells decreases from 96.5% before the field test to 90.5% and the water cut of another 8 edge wells decreases from 95.5% before the field test to 92.4% (Seen in Fig.13). A better development effect has been seen in the production wells located at distributary streamline, its average single well accumulative oil increase is 1788t more than that of production wells located at main streamline, so remaining oil distribution are the main factor influencing on the development effect after polymer flooding [25][26][27][28][29] .…”

Section: Remaining Oil Distribution After Polymer Flooding Is a Majormentioning

confidence: 99%

High Concentration Polymer Flooding Field Test With Well Infilling to Change Fluid Flowing Direction After Polymer Flooding

Gao

Jiang

Zhang

et al. 2016

Day 2 Tue, March 22, 2016

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There are about half reserves remaining underground after polymer flooding, which are huge reserves for further tapping. So how to enhance oil recovery greatly after polymer flooding has been a major technical challenge in china or abroad. According to the data of 20 pressure coring wells after polymer flooding, the places where remaining oil locate are precisely described in this paper and on the basis of laboratory research and numerical simulation and geological study, a new method has been developed that combines well pattern restructuring for changing fluid flowing direction and high concentration polymer flooding so as to tap remaining oil which scatters highly and enriches relatively in distributary streamline after polymer flooding. Field test which used this new method has been carried out at B2D block in Daqing oilfield after polymer flooding. In order to get optimum mobility control, a reasonable formula of high concentration polymer system is optimized and the molecular weight and concentration of polymer are respectively 25 million and 2500 mg/L. Some good responses have been obtained in this field test. The injection pressure has increased by 4.3 MPa and the fluid absorption thickness ratio has increased by 26.3% and water cut drop maximum of central well has reached 16% and its incremental oil recovery is 5%. Based on this field test, it can be concluded that whether a field test after polymer flooding can get a good development effect, well pattern infilling is a premise and remaining oil distribution is a major influential factor and reasonable mobility ratio and injection-production ratio are important safeguards. High concentration polymer flooding with well infilling to change fluid flowing direction is a very effective technology to enhance oil recovery after polymer flooding. This technology has gain very good technological and economic effect, its final incremental oil recovery is 6.77% predicted by numerical simulation and its internal rate of return is 21.9%. This technology has wide application prospects and can be widely applied in blocks of Daqing oilfield after polymer flooding.

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“…Typical SP flooding can increase oil recovery by more than 15% OOIP [15]. SP flooding is believed the development trend of chemical flooding in China [13,16], and five large-scale field tests have been carried out by China National Petroleum Company (CNPC) since 2011 [13]. Although a successful single-well SP field test was reported in Hungary [17], large-scale SP flooding field tests were only reported in China.…”

Section: Introductionmentioning

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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Recent Progress and Effects Analysis of Foam Flooding Field Tests in China

Cited by 20 publications

References 1 publication

Fractional-Flow Theory for Non-Newtonian Surfactant-Alternating-Gas Foam Processes

Fractional-Flow Theory for Non-Newtonian Surfactant-Alternating-Gas Foam Processes

High Concentration Polymer Flooding Field Test With Well Infilling to Change Fluid Flowing Direction After Polymer Flooding

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

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