Digital Oil Model Development and Verification

2021 ◽  
Author(s):  
Vai Yee Hon ◽  
Ismail Mohd Saaid ◽  
Ching Hsia Ivy Chai ◽  
Noor 'Aliaa M. Fauzi ◽  
Estelle Deguillard ◽  
...  

Abstract Advances in digital technologies have the potential to enhance model predictive capability and redefine its boundaries at various scale. Digital oil with accurate representation of atomistic components is a powerful tool to analyze both macroscopic properties and microscopic phenomena of crude oil under any thermodynamic conditions. Digital oil model presented in this paper is the key input in molecular chemistry modeling for designing chemical enhanced oil recovery formulation. Hence, it is constructed based on a fit-for purpose strategy focusing in oil components that have large contribution to microemulsion stability. Complete crude oil composition could comprise over 100,000 components. Lengthy simulation time is required to simulate all crude oil components which is impratical, despite the challenges to identify all crude oil components experimentally. Therefore, we established a practical experimental strategy to identify key crude oil components and constructed the digital oil model based on surrogate components. The surrogate components are representative molecules of the volatiles, saturates, aromatics and resins. Two-dimensional digital oil model, with aromaticity on one axis, and the size of the molecules on the other axis was constructed. We developed algorithm to integrate nuclear magnetic resonance response with architecture of the molecular structure. A group contribution method was implemented to ensure reliable representation of the molecular structure. We constructed the digital oil models for a field in Malaysia Basin. We validated the physical properties of the digital oil model with properties measured from experiment, predicted from molecular dynamics simulation and calculated from quantitative property-property relationship method. Good agreement was obtained from the validation, with less than 5% and 13% variance in crude density and Equivalent Alkane Carbon Number respectively, indicating that the molecular characteristic of the digital oil model was captured correctly. We adopted the digital oil model in molecular chemistry modeling to gain insights into microemulsion formation in chemical enhanced oil recovery formulation design. Digital oil is a robust tool to make predictions when information cannot be extracted from experimental data alone. It can be extended for engineering applications involving processing, safety, hazard, and environmental considerations.

RSC Advances ◽  
2015 ◽  
Vol 5 (18) ◽  
pp. 13993-14001 ◽  
Author(s):  
Jianhui Zhao ◽  
Caili Dai ◽  
Qinfang Ding ◽  
Mingyong Du ◽  
Haishun Feng ◽  
...  

The molecular structure has an important effect on the surface and interfacial properties of sulfobetaine surfactant at both air–water and crude oil–water interfaces.


1977 ◽  
Vol 17 (03) ◽  
pp. 193-200 ◽  
Author(s):  
M.C. Puerto ◽  
W.W. Gale

Abstract Economic constraints are such that it is unlikely a pure surfactant will be used for major enhanced oil recovery projects. However, it is possible to manufacture at competitive prices classes of syntheic and natural petroleum sulfonates that have fairly narrow molecular-weight distributions. Under some reservoir conditions, one of these narrow-distribution sulfonates may serve quite well as the basic component of a surfactant flood, however, in many instances a mixture of two or more of these may be required. Since evaluation of a significant subset of "all possible combinations" is a formidable undertaking screening techniques must be established that can reduce the number of laboratory core floods required. It is well known that interfacial tension plays a dominant role in surfactant flooding. It has recently been shown that minimal interfacial tensions occur at optimal salinity, Cphi, where the solubilization parameters VO/Vs and Vw/Vs are equal. Additionally, it has been shown that interracial tensions are inversely proportional to the magnitude of the solubilization parameters. This paper demonstrates that optimal salinity and solubilization parameters for any mixture of orthoxylene sulfonates can be estimated by summation of mole-fraction-weighted component properties. Those properties, which could not be properties. Those properties, which could not be measured directly, were obtained by least-squares regression on mixture data. Moreover, for surfactants of known carbon number distributions, equations that are linear in mole fractions of components and logarithmic in alkyl carbon number were found to be excellent estimators of both Cphi and solubilization parameters evaluated at Cphi. parameters evaluated at Cphi. Optimal salinity and associated solubilization parameters were measured using constant weight parameters were measured using constant weight fractions of alcohol cosolvents and mixtures of seven products with narrow molecular weight distributions. The average alkyl carbon number of these products varied from about 8 to 19. Alkyl chain lengths of individual surfactant chemical species ranged from 6 to 24 carbon atoms. Introduction Optimal salinity and the amounts of oil and water contained in a microemulsion have been shown to play important roles in obtaining low interfacial tensions and high oil recoveries. Since economics of enhanced oil recovery projects demand use of inexpensive surfactants, broad-distribution products likely will be chosen. Knowledge of how to estimate optimal salinity and oil-water contents of microemulsions prepared from such products would reduce time involved in laboratory screening procedures. This paper presents a method for procedures. This paper presents a method for obtaining such estimates that should prove useful for all types of surfactant mixtures that involve homologous series. The basic concept used is that a given property of a mixture of components (Yi) is related to the sum of products of mole fraction of components in the mixture (Xij) and the "mixing value" of the property in question for that component (Y'j). In property in question for that component (Y'j). In other words, (1) This approach is similar, for example, to the pseudocritical method used by Kay to calculate pseudocritical method used by Kay to calculate gas deviation factors at high pressures. The properties of interest in this paper are optimal properties of interest in this paper are optimal salinity and solubilization parameters, Vo/Vs, and Vw/Vs, at optimal salinity. Two separate approaches were developed that depended on the degree of detail of the available surfactant-composition data. In the first approach, only average molecular weights of several surfactant products were assumed known. Optimal salinity and products were assumed known. Optimal salinity and solubilization parameters could be measured for some, but not all, of the products. Regression on mixture data was used to estimate these quantities for the remainder of the products. Those properties, either measured experimentally or estimated from mixture data, are referred to as surfactant product contributions since they can be used as mixing values of the property in question in Eq. 1 or Eq. 2. SPEJ P. 193


SPE Journal ◽  
2018 ◽  
Vol 23 (03) ◽  
pp. 803-818 ◽  
Author(s):  
Mehrnoosh Moradi Bidhendi ◽  
Griselda Garcia-Olvera ◽  
Brendon Morin ◽  
John S. Oakey ◽  
Vladimir Alvarado

Summary Injection of water with a designed chemistry has been proposed as a novel enhanced-oil-recovery (EOR) method, commonly referred to as low-salinity (LS) or smart waterflooding, among other labels. The multiple names encompass a family of EOR methods that rely on modifying injection-water chemistry to increase oil recovery. Despite successful laboratory experiments and field trials, underlying EOR mechanisms remain controversial and poorly understood. At present, the vast majority of the proposed mechanisms rely on rock/fluid interactions. In this work, we propose an alternative fluid/fluid interaction mechanism (i.e., an increase in crude-oil/water interfacial viscoelasticity upon injection of designed brine as a suppressor of oil trapping by snap-off). A crude oil from Wyoming was selected for its known interfacial responsiveness to water chemistry. Brines were prepared with analytic-grade salts to test the effect of specific anions and cations. The brines’ ionic strengths were modified by dilution with deionized water to the desired salinity. A battery of experiments was performed to show a link between dynamic interfacial viscoelasticity and recovery. Experiments include double-wall ring interfacial rheometry, direct visualization on microfluidic devices, and coreflooding experiments in Berea sandstone cores. Interfacial rheological results show that interfacial viscoelasticity generally increases as brine salinity is decreased, regardless of which cations and anions are present in brine. However, the rate of elasticity buildup and the plateau value depend on specific ions available in solution. Snap-off analysis in a microfluidic device, consisting of a flow-focusing geometry, demonstrates that increased viscoelasticity suppresses interfacial pinch-off, and sustains a more continuous oil phase. This effect was examined in coreflooding experiments with sodium sulfate brines. Corefloods were designed to limit wettability alteration by maintaining a low temperature (25°C) and short aging times. Geochemical analysis provided information on in-situ water chemistry. Oil-recovery and pressure responses were shown to directly correlate with interfacial elasticity [i.e., recovery factor (RF) is consistently greater the larger the induced interfacial viscoelasticity for the system examined in this paper]. Our results demonstrate that a largely overlooked interfacial effect of engineered waterflooding can serve as an alternative and more complete explanation of LS or engineered waterflooding recovery. This new mechanism offers a direction to design water chemistry for optimized waterflooding recovery in engineered water-chemistry processes, and opens a new route to design EOR methods.


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