Base Number and Wetting Properties of Crude Oils

Dubey, Sheila; Doe, Peter H.

doi:10.2118/22598-pa

Cited by 203 publications

(119 citation statements)

References 19 publications

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“…The surface charge of the formation rock has a key role on the surfactant adsorption which is a strong function of the pH, so the adsorption of the most commonly used anionic surfactants typically decreases with an increase in pH. Dubey and Doe (1993) showed that at reservoir pH conditions, silica and clay surfaces as well as crude oil include negative electrical charge. At neutral pH, clays have a negative charge on the faces and a positive charge at the edges.…”

Section: Surfactant Mechanisms: Wettability Alterationmentioning

confidence: 99%

Evaluation of surfactant flooding using interwell tracer analysis

Khaledialidusti

Kleppe

Enayatpour

2016

J Petrol Explor Prod Technol

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Surfactant flooding is an important enhanced oil recovery (EOR) method, especially in carbonate oil reservoirs where water flooding may not have an effect on oil recovery as much as for sandstone reservoirs. This is because of the initial wettability of most carbonate reservoirs that is mixed-or oil-wet. Since surfactant flooding has a great impact on both fluid-fluid and rock-fluid interactions, it can be an efficient EOR method for these kinds of reservoirs. Surfactants affect fluid-fluid interactions by reducing interfacial tension (IFT) between water and oil phases and rock-fluid interactions by wettability alteration. The objective of this paper is the evaluation of these two surfactant mechanisms in non-fractured carbonate reservoirs using UTCHEM, the University of Texas chemical compositional simulator. In this paper, first, the laboratory data of two surfactant spontaneous imbibition tests for carbonate cores are successfully matched with modeled data to evaluate the mechanisms of surfactant flooding. Second, the field-scale surfactant flooding is simulated using the experimental data from spontaneous imbibition tests. Several cases are modeled in order to study the effect of surfactant flooding in terms of decreasing IFT and wettability alteration. Since the formation brine salinity in most reservoirs is more than the optimum salinity of surfactant phase behavior, the benefit of combining surfactant and low-salinity water is also investigated. Finally, tracer test simulation is performed to estimate the average oil saturation within the swept pore volume at the end of each recovery mode.

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Section: Surfactant Mechanisms: Wettability Alterationmentioning

confidence: 99%

Evaluation of surfactant flooding using interwell tracer analysis

Khaledialidusti

Kleppe

Enayatpour

2016

J Petrol Explor Prod Technol

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“…Asphaltenes as colloidal with various sizes or as individual molecules can be absorbed on solid surfaces by the virtue of their weak phenolic and carboxylic acid groups (Kokal et al 1995). These materials can also be strongly deposited on mineral surfaces and reservoir rocks, and hence cause formation damage, and hinder oil recovery from the reservoirs (Dubey and Doe 1993;Kord et al 2012;Zanganeh et al 2012). Furthermore, the absorption and deposition of asphaltenes on steel surfaces would restrict oil flow in transportation pipelines (Faus et al 1984;Mochida et al 1988).…”

Section: Introductionmentioning

confidence: 99%

Investigation of asphaltene deposition under dynamic flow conditions

Salimi

Abdollahifar

2016

Pet. Sci.

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Asphaltene deposition is one of the most serious problems, which usually occurs in oil wells, petroleum production, oil processing, and transportation facilities. Deposition of heavy organic components, especially asphaltene, can lead to wellbore blockage and impacts well economics due to reduction in oil production. Therefore, it is necessary to pay more attention to finding some solution to overcome this problem. In this study, a pipe-loop apparatus for investigation of oil stability was employed to measure deposition thickness using a thermal method. The effects of many factors such as oil type, oil temperature, oil velocity, inhibitors, and solvents on asphaltene deposition were investigated. The results showed that the deposition increased with the increasing value of the colloidal instability index. Besides, the deposition thickness increased with the decreasing velocity of oil, but did not change with oil temperature. In addition, n-heptane could result in more deposition; however, toluene had no effect on the deposition. Branched dodecyl benzene sulfonic acid (Branched DBSA) and Linear DBSA as inhibitors decreased the rate of asphaltene deposition.

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“…Dubey and Doe (1993) showed a high degree of non-water-wetness of silicates could be attributed to a high base number, assuming the base number was measured accurately. Although acids are more likely to interact with carbonate surfaces, neglecting the presence of basic components that may compete for interactions with crude oil acids may help to account for some of the discrepancies in the literature.…”

Section: Brinementioning

confidence: 96%

Wettability and Oil Recovery by Imbibition and Viscous Displacement from Fractured and Heterogeneous Carbonates

Morrow¹,

Buckley²

2006

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About one-half of U.S. oil reserves are held in carbonate formations. The remaining oil in carbonate reservoirs is regarded as the major domestic target for improved oil recovery. Carbonate reservoirs are often fractured and have great complexity even at the core scale. Formation evaluation and prediction is often subject to great uncertainty. This study addresses quantification of crude oil/brine/rock interactions and the impact of reservoir heterogeneity on oil recovery by spontaneous imbibition and viscous displacement from pore to field scale.Wettability-alteration characteristics of crude oils were measured at calcite and dolomite surfaces and related to the properties of the crude oils through asphaltene content, acid and base numbers, and refractive index. Oil recovery was investigated for a selection of limestones and dolomites that cover over three orders of magnitude in permeability and a factor of four variation in porosity. Wettability control was achieved by adsorption from crude oils obtained from producing carbonate reservoirs. The induced wettability states were compared with those measured for reservoir cores. The prepared cores were used to investigate oil recovery by spontaneous imbibition and viscous displacement. The results of imbibition tests were used in wettability characterization and to develop mass transfer functions for application in reservoir simulation of fractured carbonates. Studies of viscous displacement in carbonates focused on the unexpected but repeatedly observed sensitivity of oil recovery to injection rate. The main variables were pore structure, mobility ratio, and wettability. The potential for improved oil recovery from rate-sensitive carbonate reservoirs by increased injection pressure, increased injectivity, decreased well spacing or reduction of interfacial tension was evaluated. Table A2. Contact angles on cleaved calcite after aging in crude oil (initially dry or wet with the same aqueous phase as that used to float off bulk oil)…………………………53 Table 2.1 Synthetic brine composition…………………………………………………..87 Table 2.2 Selected properties of crude oil samples………………………………………87 Table 2.3 Gambier and Edwards (GC) cores tested for the effect of initial water saturation. Table 2.4 Edwards (GC) cores tested for the effect of aging time for Cottonwood crude oil………………………………………………………………………………………...88 Table 2.5 Gambier and Edwards (GC) MXW-F cores tested for wetting stability and the effect of oil phase viscosity …………………………………………………………89 Table 3.1 Synthetic brine composition…………………………………………………104 Table 3.2 Edwards (GC) cores tested with different mineral oil viscosities…………...105 Table 3.3 Edwards (GC) cores tested for the effect of variation in core length (µ o = 3.8cP). Fig. 1.10 AFM image of calcite exposed first to (0.1M NaCl) brine then aged for 2 days and 21 days in E-1XD-00 crude oil (deflection image in water)………………………..37 Fig. 1.11 AFM image of calcite exposed first to (0.1M NaCl) brine then aged for 2 days and 21 days in Tensleep crude oil (deflection image...

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Base Number and Wetting Properties of Crude Oils

Cited by 203 publications

References 19 publications

Evaluation of surfactant flooding using interwell tracer analysis

Evaluation of surfactant flooding using interwell tracer analysis

Investigation of asphaltene deposition under dynamic flow conditions

Wettability and Oil Recovery by Imbibition and Viscous Displacement from Fractured and Heterogeneous Carbonates

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