Advances in Oil and Water Saturation Measurements Using Low Field NMR

Bryan, J.; Thuy, An; Hum, Florence M.; Kantzas, Apostolos

doi:10.2118/97802-ms

Cited by 4 publications

(2 citation statements)

References 15 publications

(27 reference statements)

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“…The following equation showed how to calculate water saturation (S w ), as a weight fraction. It has been proven that the signals from bitumen and clay bound water may overlap in the NMR spectra 4,5 , and it is still under investigation on how to differentiate the two fluids from NMR spectra only. The combination algorithm developed in this work calculated water weight by using the results of both density and NMR experiments.…”

Section: Experimental Methodologymentioning

confidence: 99%

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Bituminous Ore Characterization by Integrating Low-Field NMR With Density and Particle Size Distribution Measurements

Niu

Kantzas

2007

Canadian International Petroleum Conference

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Low field NMR was demonstrated as a useful tool for a fast, non-destructive method to calculate the bitumen, water and solids content of oil sands ore. However, on occasion it was found that the presence of clay bound water ends up overlapping the bitumen NMR signals. Thus in such cases it is difficult to accurately determine fluid content from T 2 relaxation only. This paper proposes a somewhat more complex method for the determination of fluid and solids content of oil sands by integrating a density measurement to the NMR algorithm. By a fast measurement of both the weight and the volume of the sample and subsequently its bulk density, an independent solid content estimate is provided, which in turn helps in tightening up the fluid content estimates. Preliminary work to date indicates that the combined density-NMR method matches much better the results of Dean-Stark extraction than NMR alone. Particle size distribution analysis of the solids after Dean-Stark extraction is also shown to correlate with the fast relaxation components of the water spectra in both oil sands ore and in water saturated sand extracted from the ore. The latter is obtained through a vacuum saturation step of the extracted sand by brine, followed by a centrifugal desaturation of the sand to irreducible saturation. The methodology was tested using samples from four wells from Athabasca oil sands. Methodology and results are presented in the paper.

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Section: Experimental Methodologymentioning

confidence: 99%

“…Previous works 1,2,3,4,5 have shown that for water and bitumen content, there was a correlation between NMR-based algorithm and Dean-Stark extraction. For the time being, DeanStark method is an accepted industry standard for core analysis.…”

Section: Introductionmentioning

confidence: 93%

Bituminous Ore Characterization by Integrating Low-Field NMR With Density and Particle Size Distribution Measurements

Niu

Kantzas

2007

Canadian International Petroleum Conference

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Integrated Approach to Analyze the Compatibility and Performance of Electrokinetic Low-Concentration Acid IOR in Heterogeneous Abu Dhabi Carbonate Reservoirs

et al. 2016

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The increasing global demand for additional energy requirement forecasted upto 74% in 2030 has made Improved Oil recovery (IOR) at the forefront of oil and gas R&D for the past 4 decades as it helps in the improvement of the hydrocarbon sweep efficiency. In carbonate reservoirs, there is a challenge of having large fractions of unswept oil, mainly due to permeability damage, heterogeneous formation or unfavourable petrophysical properties. Conventional acidizing, though useful in increasing the effective permeability in the near well-bore region, has issues of limited depth of penetration, as acid is consumed and adsorbed early into the formation. However, the application of Electrokinetic Low-concentration acid IOR (EK LCA-IOR), where conventional low-concentration acidizing (LCA-IOR) is coupled with electrokinetic enhanced oil recovery (EK-EOR) , has resulted in targeting the previously immobile oil, significantly improving the capillary number while minimizing acid consumption and adsorption.This study demonstrates an integrated approach using Single Energy Computed-tomography (SECT) scan imaging and Nuclear Magnetic Resonance (NMR) to analyze the compatibility and effectiveness of EK LCA-IOR in carbonate reservoirs through an increase in depth of penetration. Core-flood experiments at Abu Dhabi reservoir conditions conducted on 1-foot core-plug, involved waterflooding followed by LCA-IOR, assisted by electrokinetics in both sequential and simultaneous fashion, identifying optimum conditions (1.2% HCl concentration, 1V/cm voltage gradient).The use of SECT images of core-plug before and after the experiments, confirmed wormhole orientation and propagation length across heterogeneous core-plugs. NMR was used to identify and confirm various reservoir rock types (RRTs)that were tested allowing us to expand the range of optimum current densities and acid concentration for the EK LCA-IOR process to meet the objectives of this study in maximizing displacement efficiency and permeability enhancement.Findings confirm EK LCA-IOR application resulted in additional 15-35% displacement efficiency beyond the waterflooding limit (60%). In addition, the maximum permeability enhancement of 53% was recorded and made possible using the simultaneous approach. SECT imaging confirmed that the maxi-mum penetration depth of the injected acid was achieved using the simultaneous approach as the enhancement of depth of penetration was 82% and 70% in simultaneous and sequential approach, respectively. Furthermore, NMR results indicate that EK LCA-IOR is promising across heterogeneous formations, which allows us to optimize the process for each unique formation, using the identified operating parameters increasing displacement efficiency by 35% and permeability enhancement by 28%.EK LCA-IOR may be developed as an environomic technology targeting the reduction of power consumption and acid/water requirement upto 70% as compared to conventional IOR processes. This study takes advantage of integrating imaging capability of SECT & NMR in orde...

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Dynamic Immiscible Flood Monitoring in Sand Packs Via Frequency Domain Reflectometry

Kuznetcov

Kantzas

Bryant

2020

Day 3 Thu, December 03, 2020

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Dynamic saturation distribution of fluids in oil reservoirs is arguably the most important piece of information petroleum engineers and geophysicists need. It allows them to better characterize oil fields, choose right enhanced oil recovery techniques and make accurate recovery forecasts. The main objective of the present paper is to develop and test a novel non-intrusive technology that enables real time in-situ monitoring of fluid saturations in porous media during immiscible floods. To achieve this goal we designed, constructed and commissioned a high pressure (up to 25MPa) and temperature (up to 200°C) core-holder with an antenna that allows for low power electromagnetic sweeps in the radio frequency range. A novel inversion algorithm was created and incorporated with our core-holder-pump system that enables dynamic acquisition of the oil and water saturations. Experiments were conducted through sand packs saturated with water and then displaced with oils of varying viscosity (drainage) followed by water flooding (imbibition). Reflection and transmission coefficients in the frequency domain were measured while flooding using a commercial vector network analyzer connected to the core holder. Recorded frequency data was processed with the novel high-resolution inversion technique to obtain impulse reflection and transmission responses in the time domain. These responses were further normalized to dynamically track the water-oil volumetric saturations within the porous media. Every displacement experiment has been performed in both vertical and horizontal positions to emulate water-oil override and underride scenarios. Material balance calculations were performed to validate fluid saturation profiles for all imbibition and drainage experiments every 5 % of the pore volume of the fluids injected. Frequency domain reflection and transmission electromagnetic responses were measured every 1 % of the fluid injected. Material balance was used to validate the measured saturation profiles. The goodness of fit was calculated between these two independent measurements for every flood experiment performed. The mean-square error was calculated to be around 1.26% of the total pore volume on average. Late breakthroughs and piston-like displacement were observed in the floods with favorable mobility ratios. In contrast, much earlier breakthroughs have been registered in all the experiments with unfavorable mobility ratios due to fingering. All our observations are in agreement with the current theory of immiscible displacement in porous media. The novel automated system paired with the inversion algorithm were developed to allow for virtually real time monitoring of the fluid saturations during imbibition and drainage displacement cycles. Our technology is shown to be a promising candidate to compliment resistive logging measurements in the field.

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Advances in Oil and Water Saturation Measurements Using Low Field NMR

Cited by 4 publications

References 15 publications

Bituminous Ore Characterization by Integrating Low-Field NMR With Density and Particle Size Distribution Measurements

Bituminous Ore Characterization by Integrating Low-Field NMR With Density and Particle Size Distribution Measurements

Integrated Approach to Analyze the Compatibility and Performance of Electrokinetic Low-Concentration Acid IOR in Heterogeneous Abu Dhabi Carbonate Reservoirs

Dynamic Immiscible Flood Monitoring in Sand Packs Via Frequency Domain Reflectometry

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