I hereby declare that I am responsible for the work submitted in this project, that the original work is mine except as specified in the references and acknowledgments, and that the original work contained herein was not performed or performed by anyone other than -specified sources or persons. . A high degree of accuracy is required for predicting the outcome of the gas injection process due to the high costs associated with the gas injection operation. The purpose of this study was to reduce the error of prediction due to correlation.
This study suggests the inclusion of a paraffin factor in the correlation to further characterize oil composition and reduce error. The paraffin factor was used to measure the limit of paraffin that could fit the correlations and to improve the correlation. In contrast, the Glas correlation was suitable for crude oil having a paraffin factor value greater than 11.6, while the Cronquist correlation was suitable for crude oil having a paraffin factor value greater than 11.74, as the error less important.
Glaso correlation can be further improved by including the paraffinicity factor and reducing the mean deviation error to 9.49% from 12.23%. Last but not least, to Universiti Teknologi PETRONAS for providing the laboratory facilities to carry out the experiments.
INTRODUCTION
- B ACKGROUND S TUDY
- P ROBLEM S TATEMENT
- O BJECTIVES
- S COPE OF THE S TUDY
- T HE R ELEVANCY OF THE P ROJECT
- F EASIBILITY OF THE P ROJECT
In addition, most correlation relies on the molecular weight distribution of the C7+ fraction to characterize the reservoir fluid. Improvement in correlations or development of a universal correlation that can adapt to any type of reservoir fluid and predict the minimum mixing pressure with less error is important as it can save a lot of time and cost. Accurate prediction of MMP also helps in developing reservoir management strategies that can maximize the efficiency of gas injection performance.
A total of 79 MMP measurements obtained from the literature and 4 points MMP of the experimental MMP from this current study were used as the dataset. Having research on the minimum miscibility pressure correlation will help to improve the estimation of MMP for the paraffinic and asphaltenic crude oil by reducing the uncertainty in the correlations. Based on the given time which is 7 months period (FYP 1 and FYP 2), this research is expected to be fully utilized within the scope and time frame of the study.
The first few weeks will be focused on studying the topic and the equipment that will be used. The time allotted for each experiment was designed to be able to achieve the objectives of the research.
LITERATURE REVIEW
- CO 2 M ISCIBLE I NJECTION F LOODING
- F ACTORS A FFECTING M INIMUM M ISCIBILITY P RESSURE
- CO 2 Purity
- Oil composition
- Reservoir Temperature
- P ARAFINICITY F ACTOR
- MMP C ORRELATIONS
- W. F. Yellig and R. S. Metcalfe (1980)
- Glaso (1985)
- Yuan (2004)
- L ABORATORY M ETHODS TO M EASURE MMP
- Slim Tube Method
- Vanishing Interfacial Tension Technique
On the other hand, ethane and higher molecular weight hydrocarbons in CO2 can reduce the required pressure. This is because a high molecular weight will reduce the solubility of the hydrocarbon in CO2. they were comparatively easy to extract. For heavy crude oil containing low C5 to C20 intermediates, extraction was inefficient under all conditions. 1987) who reported that the molecular weight distribution present in the oil is the most important factor affecting MMP.
In addition to molecular weight distribution, the development of CO2/oil miscibility also depends on the chemical type of the heavy hydrocarbons such as paraffins, naphthenes and aromatics. Although the effect of variations in the structure of the hydrocarbon molecules on the evolution of miscibility is minor, further characterization of heavier components was believed to be important to achieve accurate MMP prediction. Since the density of CO2 is proportional to the amount of hydrocarbon extracted, this will reduce the MMP.
To facilitate screening procedures and to gain insight into the mixed displacement process, many correlations have been proposed that relate the MMP to the physical properties of the displacing oil and gas. Given the same molecular weight of the C7+ fraction, some reservoir fluids may have different paraffinicity and aromaticity. However, these correlations do not further characterize the components within the C7+ fractions and as a result often produce inaccurate predictions of the minimum mixing pressure.
In addition, these correlations are using their regional reservoir fluid as the data set when developing the correlations. This correlation was used during preliminary screening due to the simplicity of the correlation that only needs the reservoir temperature parameter. Studies by Glaso (1985) show that for hydrocarbon systems, paraffinicity has an effect on MMP. the molecular weight of the oil is corrected to a K factor of 11.95, thus accounting for the different parafinity.
The determination of MMP using the interfacial tension technique is based on the measurement of the interfacial tension between injected gas and oil at constant temperature and varying pressure. The mixture of injected gas and oil is evaluated based on the IFT that disappears between the two phases. IFT values are determined from the static drop profile of the hanger for a given density change.
METHODOLOGY
- E XPERIMENT S AMPLES
- E XPERIMENT P ROCEDURE
- E QUIPMENT
- G ANTT C HART FOR P ROJECT A CTIVITIES
- K EY M ILESTONE
The interfacial tension between Dulang and Dubai crude oil with carbon dioxide was measured based on the workflow in Figure 7. The measurement is based on the proven oscillating U-tube principle that ensures very accurate density values. Knowledge of density Anton Paar DMA 4500M and IFT OPMAN 700 equipment Experiment design and initiation of the experiment.
RESULT AND DISSCUSION
- R ESULTS OF MMP BY V ANISHING I NTERFACIAL T ENSION
- R ESULTS OF THE C OMPARISON BETWEEN THE T RUE MMP WITH THE P REDICTED
- E FFECT OF P ARAFINICITY F ACTOR TOWARDS MMP
- I MPROVEMENT ON E MPIRICAL C ORRELATION
A data set of relevant information of experimentally measured MMP carbon dioxide/crude oil composition was constructed to evaluate the reliability of Yuan, Glaso, Cronquist and Yellig correlations. Oil with a K factor greater than 11.95 represents oil with high paraffin while oil with a K factor less than 11.95 represents oil with a high content of aromatic compounds. The Yuan and Yellig correlation seems to be unreliable in the K-factor value as the deviation of the predicted MMP from the true MMP is quite significant and does not show any significant trend.
In contrast, the Glaso and Cronquist correlation appears to be reliable in crude oil parafinity as the predicted deviation from the true MMP is small for this data set. Based on Table 11, the Glaso prediction had a good agreement with the true MMP until the K factor value was 11.6, where the error deviation starts to increase to 34.78%. Whereas, the Cronquist correlation had a good agreement with the true MMP until the value of the K factor was 11.74, where the error deviation starts to be significant.
Only C5+ molecular weight was used as one of the parameters for MMP determination. At a K factor of 11.74 and below, the Cronquist correlation begins to deviate significantly from the true MMP. It was also found that at low temperatures, especially below 120⁰F, the correlation prediction of Glas and Cronquist deviated significantly from the true MMP.
Based on Table 10 and Table 11, it was suspected that the insufficient description of heavier hydrocarbons causes the deviation error between the prediction and the true MMP. To verify the suggestion, this study included the parafinity factor in the Glaso correlation to reduce the error between the prediction and the true MMP. Parafinity factor greater than 11.95 represents oil with high paraffin while oil with parafinity factor less than 11.95 represents oil with high content of aromatic compounds.
The parafinity factor was included in the Glaso equation and the deviation error between the improved correlation and the true MMP was compared. By including the parafinity factor in the Glaso correlation, the error deviation between the prediction and the true MMP was reduced to 9.78 and 8.12 per. The data that was used to fit the enhanced correlation was collected from different parts of the world.
In addition, the improved correlation can be applied for a wide range of K-factor from 13.64 to 11.06. It was believed that the improved correlation could predict the MMP for the paraffinic and asphaltenic crude oil.
CONCLUSION AND RECOMMENDATION
C ONCLUSIONS
R ECOMMENDATIONS
Phase equilibria for enhanced oil recovery in an n-butane-enriched carbon dioxide + black oil system. Equilibrium phase compositions of CO2/crude oil mixtures-Part 2: Comparison of continuous multiple contact and slender tube displacement. An investigation of minimum miscibility pressure for CO2-rich injection gases with pentane-plus fraction.
Minimum miscibility pressure study for an EOR gas injection project in the Al Shaheen field, offshore Qatar. An investigation of the minimum miscibility pressure using impure C02 and 'West Texas Oil System: database, correlations and composition simulation. Effect of oil composition on minimum mixing pressure: part 1 Solubility of hydrocarbons in dense CO2.
Effects of impurities on minimum miscibility pressures and minimum enrichment levels for CO2 and rig gas displacements. A reliable correlation for predicting the change in minimum miscibility pressure when CO2 is diluted with other gases. 2012) An assessment of a CO2 flood for EOR and sequestration benefits in the Ordos Basin, Northwest China.
Evaluation of CO2 Gas Injection for Major Oil Production Fields in Malaysia - Case Study for Experimental Approach: Dulang Field.
C OMPOSITION OF D ULANG C RUDE AND D UBAI C RUDE
D ULANG AND D UBAI C RUDE P ARAMETERS FOR C ORRELATION
P ROPERTIES OF C RUDE F OUND I N THE L ITERATURE
