Reducing the Uncertainty on Residual Oil Saturation in a Gas Injection Pilot Project

2002 ◽  
Author(s):  
Asbjorn Gyllensten ◽  
Mario J.C. Petricola
Keyword(s):  
Gas Injection ◽  
Pilot Project ◽  
Residual Oil ◽  
Oil Saturation ◽  
Residual Oil Saturation

Correlation and Prediction of Residual Oil Saturation for Gas Injection EOR Processes

1998 ◽  
Vol 1 (02) ◽  
pp. 127-133 ◽  
Author(s):  
E.A. Lange
Keyword(s):  
Interfacial Tension ◽  
Crude Oil ◽  
Gas Injection ◽  
Solubility Parameters ◽  
Residual Oil ◽  
Displacement Efficiency ◽  
Hydrocarbon Gases ◽  
Oil Saturation ◽  
Residual Oil Saturation ◽  
Eor Processes

Abstract A promising correlation has been developed that can be used to predict miscible or near-miscible residual oil saturation, Sorm, for a wide range of injected gases, crude oils, temperature, and pressure conditions. The correlation is based on representation of the chemical and physical properties of the crude oil and the injected gas through Hildebrand solubility parameters. This approach has the advantage that characteristics of both the injected gas and crude oil are included in the correlation, in contrast to correlations based solely on properties of the injected gas. The correlation was developed using available experimental data for tertiary recovery of eight crude oils in carbonate and sandstone cores with common EOR gases (CO2, N2, CH4, CH4 + liquefied petroleum gas). Results for 45 coreflood tests at reservoir conditions collapsed along a band when Sorm was plotted as a function of the difference in solubility parameter between the injected gas and the crude oil. Results for a pure oil, decane, with CO2 lay along the same band. The success of this correlation scheme may be due to the basic characterization of the fluids and to a relationship between solubility parameters and interfacial tension. Use of the correlation requires knowledge of only injected gas composition, injected gas density, oil average molecular weight, and temperature. This empirical correlation should have utility in screening studies or in process simulation as a simple means to forecast residual oil saturations as measured in coreflood tests. The correlation can be used to predict roughly the effects of changes in pressure, temperature, or injected gas composition on residual oil saturation. A new method to predict minimum miscibility pressure based on the solubility parameter concept is also described. Introduction The miscible residual oil saturation, Sorm, is a key property for simulation and screening studies of gas injection EOR processes. This property represents the oil saturation remaining in a porous media after injection of a large bank of a high pressure gas, such as CO2, N2, or CH4, after a waterflood. The miscible residual oil saturation thus represents the local displacement efficiency of oil by the injected gas in a ternary system of oil, gas, and water. Injected gases are frequently supercritical fluids, and proposed mechanisms of oil recovery include low interfacial tension displacement, extraction, and oil swelling. Within the industry, a common parameter used in design of these processes is the minimum miscibility pressure (MMP) or minimum miscibility enrichment (MME) level for hydrocarbon gases as determined from sandpack slim-tube tests. Recent work has suggested use of reservoir-condition coreflood data in design of gas injection EOR processes instead of MMP or MME levels. Miscible recovery processes have been studied extensively, and a variety of schemes have been developed to predict MMP. In contrast to the large number of predictive schemes for MMP, few methods have been proposed to predict Sorm. Use of a capillary number correlation has been suggested, but this approach requires knowledge of interfacial tension between equilibrated phases. A correlation of residual oil saturation with pore structure in carbonates has been suggested as well as correlations of Sorm with reduced density of the injected gas for one crude oil with several hydrocarbon gases. Although interesting, these approaches do not meet the need for a general method to predict Sorm for any injected gas and any crude oil, and laboratory coreflood tests at reservoir conditions are usually recommended to determine this important measure of local displacement efficiency.

Relationship between Residual Saturations and Wettability using Pore-Network Modeling

2021 ◽  
Author(s):  
Prakash Purswani ◽  
Russell T. Johns ◽  
Zuleima T. Karpyn
Keyword(s):  
Contact Angle ◽  
Oil Recovery ◽  
Network Modeling ◽  
Pore Network ◽  
Residual Oil ◽  
Residual Saturation ◽  
Oil Saturation ◽  
Pore Network Modeling ◽  
Residual Oil Saturation ◽  
Eor Processes

Abstract The relationship between residual saturation and wettability is critical for modeling enhanced oil recovery (EOR) processes. The wetting state of a core is often quantified through Amott indices, which are estimated from the ratio of the saturation fraction that flows spontaneously to the total saturation change that occurs due to spontaneous flow and forced injection. Coreflooding experiments have shown that residual oil saturation trends against wettability indices typically show a minimum around mixed-wet conditions. Amott indices, however, provides an average measure of wettability (contact angle), which are intrinsically dependent on a variety of factors such as the initial oil saturation, aging conditions, etc. Thus, the use of Amott indices could potentially cloud the observed trends of residual saturation with wettability. Using pore network modeling (PNM), we show that residual oil saturation varies monotonically with the contact angle, which is a direct measure of wettability. That is, for fixed initial oil saturation, the residual oil saturation decreases monotonically as the reservoir becomes more water-wet (decreasing contact angle). Further, calculation of Amott indices for the PNM data sets show that a plot of the residual oil saturation versus Amott indices also shows this monotonic trend, but only if the initial oil saturation is kept fixed. Thus, for the cases presented here, we show that there is no minimum residual saturation at mixed-wet conditions as wettability changes. This can have important implications for low salinity waterflooding or other EOR processes where wettability is altered.

scholarly journals SURFACTANT-POLYMER FLOODING PERFORMANCE IN HETEROGENEOUS TWO-LAYERED POROUS MEDIA

2011 ◽  
Vol 12 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Muhammad Taufiq Fathaddin ◽  
Asri Nugrahanti ◽  
Putri Nurizatulshira Buang ◽  
Khaled Abdalla Elraies
Keyword(s):  
Porous Media ◽  
Oil Recovery ◽  
Polymer Flooding ◽  
Water Flooding ◽  
Residual Oil ◽  
Oil Saturation ◽  
Reservoir Heterogeneity ◽  
Residual Oil Saturation ◽  
Layered Porous Media ◽  
Multiple Porosity

In this paper, simulation study was conducted to investigate the effect of spatial heterogeneity of multiple porosity fields on oil recovery, residual oil and microemulsion saturation. The generated porosity fields were applied into UTCHEM for simulating surfactant-polymer flooding in heterogeneous two-layered porous media. From the analysis, surfactant-polymer flooding was more sensitive than water flooding to the spatial distribution of multiple porosity fields. Residual oil saturation in upper and lower layers after water and polymer flooding was about the same with the reservoir heterogeneity. On the other hand, residual oil saturation in the two layers after surfactant-polymer flooding became more unequal as surfactant concentration increased. Surfactant-polymer flooding had higher oil recovery than water and polymer flooding within the range studied. The variation of oil recovery due to the reservoir heterogeneity was under 9.2%.

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