Asphaltene Inhibitor Evaluation in CO2 Floods: Laboratory Study and Field Testing

Yin, Yuebang; Yen, Andrew; Asomaning, Sam

doi:10.2118/59706-ms

Cited by 14 publications

(4 citation statements)

References 9 publications

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“…Early results were reported by Allenson et al The authors determined the critical CO 2 concentration for asphaltene precipitation high p and T for a reconditioned South American live crude oil by titration with CO 2 using the SDS and developed a chemical that, according to the authors, inhibited both asphaltene precipitation and deposition and sticking. Yin et al . developed and tested an inhibitor for continuous capillary injection to prevent asphaltene flocculation.…”

Section: Introductionmentioning

confidence: 99%

Alkanes Induced Asphaltene Precipitation Studies at High Pressure and Temperature in the Presence of Argon

et al. 2016

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The continuous increase of petroleum production under adverse subsea conditions and the preeminent need for adequate operational conditions and efficient use of additives to warrant flow assurance makes it interesting to set up experimental procedures to carry out n-alkane precipitation studies under high-pressure (p) and high-temperature (T) conditions. In this contribution, some preliminary experimental studies developed to characterize asphaltene precipitation in model systems consisting of asphaltene solutions in toluene or mixtures of hydrocarbons by the addition of propane, n-heptane, or other alkanes at various pressures and temperatures, using a commercial compact equipment, are reported. In general terms, it was established that these tests follow the same pattern described at ambient p and T conditions and the one single study reported in the literature for a stock tank oil sample at 3000 psi and room T. Four crude oils of different characteristics were tested, using diluted or undiluted samples, and it was possible to detect the asphaltene precipitation onset. However, these results cannot be used to infer the stability of the crude oils because results correlating onset and stability at high p and T are not yet available. The effect of pressure at high pressures was not entirely resolved because argon, used as an assumed inert gas to pressurize the system, dissolves in the hydrocarbons and displaces the precipitation onset toward lower values. The need to develop compact equipment to assess the effect of solvents, inhibitors, and other additives on the phase behavior of crude oil at high pressure and temperature and in the presence of CO2 and other gases, representing a valuable contribution to the petroleum industry in the area of flow assurance, still persists.

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Section: Introductionmentioning

confidence: 99%

Alkanes Induced Asphaltene Precipitation Studies at High Pressure and Temperature in the Presence of Argon

et al. 2016

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“…The application of downhole asphaltene inhibitor squeezing − , was attempted to delay asphaltene deposition in the tubing and to reduce the frequency of removal operations; however, this treatment was suspended because of insufficient response caused by inadequate adsorption of the squeezed inhibitor on the carbonate rock surface, which reduces the retention time of the effectiveness of the inhibitor to below expectation. The more conventional remedy of continuous downhole inhibitor injection ,,, was not considered a viable option because the large capital investment required workover to introduce macaroni injection lines into dual completed wells. Despite a long history of tackling the asphaltene problem, it has not yet been remedied.…”

Section: Case Studymentioning

confidence: 99%

“…As a result of this increasing CO 2 supply estimation, the growth of CO 2 EOR oil production is predicted to be sustainable during the period from 2012 to 2018, as shown in Figure . The increase in asphaltene risks by gas injection has been widely recognized. − It is therefore expected that future requirements to evaluate asphaltene flow assurance for gas injection projects will increase.…”

Section: Introductionmentioning

confidence: 99%

Contribution from Laboratory to Field: Case Studies of Asphaltene Precipitation Risk Evaluation

2016

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Three case studies pertaining to the precipitation risk of asphaltene, which comprise comprehensive evaluation from laboratory measurement to practical feedback into the field, are described. Two cases included aspects of gas injection, and the third corresponds to formation damage at a naturally depleted field. Asphaltene onset pressure (AOP) is a fundamental characteristic that represents in situ asphaltene behavior from a single-phase fluid sample; therefore, all evaluations were performed on the basis of laboratory-measured AOP data. The evaluations reported reveal how practical interpretation of laboratory-measured AOPs links appropriately to actual on-site phenomena. In the first two case studies, numerical asphaltene fluid models, calibrated using measured AOPs, were generated to evaluate asphaltene precipitation envelopes (APEs) by applying the cubic plus association equation of state. In the first case, a sensitivity analysis based on a numerical model of the original reservoir fluid was performed for several injection gases to investigate the impact of gas injection on APE behavior from the subsurface and surface points of view. In the second study, the variation of asphaltene deposits, actually observed at the gas injection pilot area, was explained by considering the vaporizing gas drive (VGD) process in terms of APE behavior. A sensitivity study was conducted to estimate how enriching the injection gas by this effect could expand the APE. An expanded APE could cause the variation of asphaltene deposits observed in the field: deposits were observed at certain times when enriched injection gas was accumulated but not when lean injection gas accumulated. Control of pressure depletion is considered an effective countermeasure to mitigate asphaltene precipitation in a naturally depleted field. For a field with a potential asphaltene deposition problem in the reservoir, it is recommended to maintain the reservoir pressure above the AOP. Such mitigation needs reliable AOP data. Once destabilized, solid particles of asphaltene grow continuously from the nanoscale (precipitation) to the microscale by aggregation. Our AOP measurements adopted the latest laboratory techniques. Three data sets were acquired using filtration, high-pressure microscopy analysis, and laser light scattering techniques. Despite using the same single-fluid sample, the AOP results were not identical because each measuring technique had different detection limits for the minimum asphaltene particle size. This paper demonstrates how we assessed the AOP data to determine the cause of asphaltene-induced formation damage by comparison to actual flowing bottomhole pressure behavior. This practical AOP measurement could suggest a more optimum pressure control target that would allow for maximum oil production while mitigating production potential loss as a result of shutdown for cleanup or removal jobs.

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“…On the other hands, the lower reservoir has not encountered any remarkable asphaltene related problems so far. The increase of asphaltene risks by gas injection has been worldwidely recognized as general rule 3,14,[16][17][18][19][20][21][22][23][24] , and a preparatory evaluation of asphaltene behavior under gas mixing condition is important to minimize its risks and to optimize gas injection project. Among available various remedies in each technology which have been widely applied in the world 1-7 , the most conventional ways have been applied in our target field.…”

Section: Introductionmentioning

confidence: 99%

Ready for Gas Injection: Asphaltene Risk Evaluation by Mathematical Modeling of Asphaltene Precipitation Envelope (APE) With Integration of all Laboratory Deliverables

Yonebayashi

Masuzawa²,

Dabbouk³

et al. 2009

All Days

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An offshore carbonate oil field in the Arabian Gulf is exhibiting asphaltene deposition problem mainly inside tubing of production wells completed in one of two main producible limestone reservoirs. This problem significantly reduces well profitability due to production loss and frequent asphaltene removal job (solvent soaking). Furthermore, future full-field EOR development, namely gas injection, is now planned and might have a risk to enhance the asphaltene problem. Therefore, comprehensive study has been carried out not only to establish less frequent and more effective remedy than the current action but also to evaluate a future risk of gas injection.The study was initiated with careful review of the fundamental measurements, collected during the 20 years production history, of asphaltene properties, i.e. SARA (saturates, aromatics, resins and asphaltenes) analysis, asphaltene contents, AOP (asphaltene onset pressure) measurement, etc. Subsequently, the mathematical modeling analysis using those properties was incorporated into the study in order to develop APE (asphaltene precipitation envelope) for better understanding/predicting of asphaltene precipitation behavior. Therefore, this paper describes the integration/optimization of the APE modeling based on all available laboratory data, and consequently suggests representative APE. The APE model validity was evaluated by comparison with actual observation data in the problematic reservoir.Based on the mathematical models once established, several sensitivities, namely mixing with injection gas and blending oils produced from two main producible reservoirs, were investigated in order to assess impacts of the future EOR on asphaltene risk from sub-surface and surface point of views. Several types of injection gas were examined, and their risks were compared and identified. Consequently, the surface facility design was adequately modified and optimized in order to minimize asphaltene risk assisted by gas injection.

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Asphaltene Inhibitor Evaluation in CO2 Floods: Laboratory Study and Field Testing

Cited by 14 publications

References 9 publications

Alkanes Induced Asphaltene Precipitation Studies at High Pressure and Temperature in the Presence of Argon

Alkanes Induced Asphaltene Precipitation Studies at High Pressure and Temperature in the Presence of Argon

Contribution from Laboratory to Field: Case Studies of Asphaltene Precipitation Risk Evaluation

Ready for Gas Injection: Asphaltene Risk Evaluation by Mathematical Modeling of Asphaltene Precipitation Envelope (APE) With Integration of all Laboratory Deliverables

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