Heavy-Oil Fluid Testing With Conventional and Novel Techniques

Goodarzi, N.N.; Bryan, J.; Mai, An; Kantzas, Apostolos

doi:10.2523/97803-ms

Cited by 3 publications

(4 citation statements)

References 6 publications

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“…Figures 4a and 4b show the oil formation volume factor and GOR behavior that differs from a conventional test. These results are consistent with observations by other researchers 9,17,18 . A capillary-flow viscometer was used to measure the oil viscosity although it was noted 9 that the effect of dispersed gas micro-bubbles (below the bubble point) on the oil viscosity may not be captured during viscosity measurements by capillary flow.…”

Section: Expansionsupporting

confidence: 94%

“…PVT Modeling: PVT data interpretation and modeling for heavy oils require a robust method for defining pseudocomponents that represent the C 7+ fraction of the oil. Since equilibrium EOS models do not capture 18,19 the oil properties with dispersed gas bubbles, these models were deliberately tuned with unconventional data obtained without agitation of the sample in the PVT cell after 48 hours at each pressure depletion step. Although this may not provide the accurate description of non-equilibrium behavior exhibited by these heavy "foamy" oils, it was assumed that this approach will provide a closer description of the oil behavior than the one predicted by the equilibrium EOS model.…”

Section: Expansionmentioning

confidence: 99%

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Challenges of Heavy Oil Fluid Sampling and Characterization

et al. 2012

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A significant portion of the world's hydrocarbon reserves is found in heavy oil reservoirs. Heavy oils are often found in shallow and highly unconsolidated reservoirs, or sometimes in deep, tight formations. Often the high asphaltic content of these oils results in relatively higher oil density and viscosity; hence, their lower reservoir mobility poses significant challenges to both sampling and PVT data measurements. Furthermore, modeling these fluids for reservoir evaluation requires special techniques to capture their unique phase behavior.The challenges of representative down-hole or surface fluid sample acquisition demand customized sampling methods to deal with:• low oil mobility • sand production from unconsolidated formations • high asphaltene content and resulting high gradients • formation of water-in-oil emulsion during co-production of water or gas lift operations or addition of diluents In addition, the prerequisite for laboratory measurement is special sample preparation to remove emulsified water. These high viscosity oils exhibit slower gas liberation below the bubble point and hence delayed gas-phase formation, thus making "true" oil property measurements a challenge. Difficulties associated with fluid modeling include characterizing apparent bubble point behavior, large viscosity changes with pressure and temperature, and asphaltene dropout.In this paper, we present a comprehensive methodology for heavy oil sampling and characterization in unconsolidated sands as well as in low permeability reservoirs. We present field examples to highlight the challenges and illustrate the methodology for fluid sampling, down-hole fluid analysis, laboratory PVT data acquisition, and modeling. Sampling methods for heavy and asphaltic oils were custom designed with special tools and sensors to obtain representative samples and precise down-hole fluid analysis data. New laboratory techniques were developed to prepare the samples for analysis and to distinguish between the "true" and "apparent" bubble point behavior exhibited by the heavy oil due to its non-equilibrium behavior. Fluid models based on a special equations of state (EoS) were employed for accurate description of heavy oil fluid phase behavior. In particular, we successfully applied the industry's first EoS for asphaltene gradients in heavy oil reservoirs that match down-hole fluid data.

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Section: Expansionsupporting

confidence: 94%

Section: Expansionmentioning

confidence: 99%

Challenges of Heavy Oil Fluid Sampling and Characterization

et al. 2012

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“…NMR can be used to assess the oil saturations at different times, help in monitoring the remaining oil saturation for different EOR techniques in the reservoir (using NMR logging) and in the laboratory (Allsopp et al 2001;Bryan et al 2006a, b;Bryan et al 2006a, b;Goodarzi et al 2005). Low-field NMR measurements can be used in the laboratory measurements to evaluate the EOR treatments for various types of conventional reservoirs (such as light and heavy oils) and unconventional reservoirs (such as shale oils) (Dong et al, 2020;Markovic et al 2020).…”

Section: Enhanced Oil Recovery Applicationsmentioning

confidence: 99%

A review on the applications of nuclear magnetic resonance (NMR) in the oil and gas industry: laboratory and field-scale measurements

Elsayed

Isah

Hiba

et al. 2022

J Petrol Explor Prod Technol

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This review presents the latest update, applications, techniques of the NMR tools in both laboratory and field scales in the oil and gas upstream industry. The applications of NMR in the laboratory scale were thoroughly reviewed and summarized such as porosity, pores size distribution, permeability, saturations, capillary pressure, and wettability. NMR is an emerging tool to evaluate the improved oil recovery techniques, and it was found to be better than the current techniques used for screening, evaluation, and assessment. For example, NMR can define the recovery of oil/gas from the different pore systems in the rocks compared to other macroscopic techniques that only assess the bulk recovery. This manuscript included different applications for the NMR in enhanced oil recovery research. Also, NMR can be used to evaluate the damage potential of drilling, completion, and production fluids laboratory and field scales. Currently, NMR is used to evaluate the emulsion droplet size and its behavior in the pore space in different applications such as enhanced oil recovery, drilling, completion, etc. NMR tools in the laboratory and field scales can be used to assess the unconventional gas resources and NMR showed a very good potential for exploration and production advancement in unconventional gas fields compared to other tools. Field applications of NMR during exploration and drilling such as logging while drilling, geosteering, etc., were reviewed as well. Finally, the future and potential research directions of NMR tools were introduced which include the application of multi-dimensional NMR and the enhancement of the signal-to-noise ratio of the collected data during the logging while drilling operations.

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“…For instance, a theory suggests that asphaltenes migrate to the surface of bubbles, which has been confirmed later in a toluene + asphaltene/methane interface, and the resulted impoverishment of the matrix in asphaltenes decreases the foamy oil viscosity . However, different experimental studies on foamy oil viscosity predict either an increase − or a decrease , in the live oil viscosity with the presence of bubbles. The influence of bubbles on the heavy oil flow properties is thus still debated.…”

Section: Introductionmentioning

confidence: 99%

Rheological Behavior of Foamy Oils

et al. 2008

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When a reservoir is depleted, the lightest components (methane, ethane, etc.) can exsolve from the crude oil and create a gaseous phase. In conventional oils, the bubbles grow and coalesce quickly and the gas usually separates from the oil (slug flow). On the contrary, in heavy oils, bubbles are small, remain dispersed, and flow within the oil for a long time. This "foamy oil" phenomenon can drastically change the flow properties of the crude oil. This paper is devoted to the characterization of the heavy oil foaming behavior through a rheological study. Our objectives are to study the kinetics of bubble evolution in heavy oil and to measure the influence of the bubbles on the heavy oil viscosity. A new experimental method was developed on the basis of rheological measurements under pressure. Several heavy oils containing dissolved gas have been depleted inside the pressure cells of controlled stress rheometers to create foamy oils. Viscosity and viscoelastic properties have been continuously measured using respectively continuous and oscillatory tests from the nucleation to the disengagement of bubbles from oil. Results reveal that, under low shear rates, the presence of bubbles leads to an increase in heavy oil viscosity, as predicted by the hard sphere model or Taylor. A theoretical model describing the viscosity of foamy oil was then established. It takes into account both first-order kinetics of the appearance and release of bubbles in oil and a classic suspension model. Good agreement was obtained between experimental data and model predictions. Several tests reveal the strong influence of the shear rate on the foamy oil behavior and point out the major role of bubble deformation on the viscosity of foamy oils, as shown previously in other viscous materials, such as magmas and polymers. Under high shear rates, we suggest that the stabilization of the elongated bubbles in oil leads to the establishment of an anisotropic material, which can be seen as a sandwich-like structure. As a result, the viscosity appears lower in the direction of the flow.

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Heavy-Oil Fluid Testing With Conventional and Novel Techniques

Cited by 3 publications

References 6 publications

Challenges of Heavy Oil Fluid Sampling and Characterization

Challenges of Heavy Oil Fluid Sampling and Characterization

A review on the applications of nuclear magnetic resonance (NMR) in the oil and gas industry: laboratory and field-scale measurements

Rheological Behavior of Foamy Oils

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