Measurement Of Minimum Miscibility Pressure Research Articles

Microfluidic Studies on Minimum Miscibility Pressure for n-Decane and CO2

Oil production is a complex process that can be made more efficient by applying gas enhanced oil recovery (EOR) methods. Thus, it is essential to know the minimum miscibility pressure (MMP) and minimum miscibility enrichment (MME) of gas in oil. Conventional slim-tube experiments for the measurement of MMP require hundreds of millilitres of real or recombined oil and last over 30 days. Advances in microfluidic technology allow the reduction of the amount of fluid and the time required in determining MMP (or MME), hence making the process rapid. In this study, we developed a microfluidic model with a stochastically distributed pore network, porosity of 74.6% and volume of 83.26 nanolitres. Although the volume was six orders of magnitude smaller than the slim tube, it retained the same proportions, guaranteeing a proper comparison between the tests. This microfluidic chip allowed the study of the MMP of n-decane with carbon dioxide at two different temperature conditions. The experimental results coincided with the results received both from conventional and microfluidic experiments. Furthermore, a numerical simulation of a section of the microfluidic model under the experimental conditions presented results within acceptable margins of the experimental ones. The results of the presented methodology indicate the potential to replace conventional technology for the measurement of MMP with microfluidic technology. Its promise lies in accelerating laboratory tests and increasing the reliability of experimental results and, subsequently, the quality of field gas EOR operations.

Prediction of minimum miscibility pressure (MMP) of the crude oil-CO2 systems within a unified and consistent machine learning framework

In this study, considering the differences of minimum miscibility pressure (MMP) measured with the slim-tube and rising bubble apparatus (RBA) methods and taking each individual compound and the parameter representing the source of MMP measurement as the input, a new machine learning model has been proposed and validated to determine MMPs of the crude oil-CO2 systems by use of the one-dimensional convolutional neural network (1D-CNN). Then, the differences of the aforementioned two MMP measurement methods and each individual factor on the predicted MMP are analyzed by using the SHapley Additive exPlanations (SHAP). Compared to the existing models that ignore the differences of MMPs obtained from different experiments and taking the pseudocomponents as the input, the newly proposed model not only has the lowest mean absolute percentage error (MAPE) of 7.29%, lowest mean square error (MSE) of 3.7916, and highest R2 of 0.9458 on the slim-tube test dataset, but also can be used to accurately reflect the relationship between the MMP and each of its influential factor. Furthermore, it is observed that there is a very good correlation between the MMP measured with the slim-tube and the RBA methods to capture the corresponding physics in such two experiments within a unified, consistent, and efficient framework.

Microscopic transport and phase behaviors of CO2 injection in heterogeneous formations using microfluidics

CO2 injection into the geological formations is a promising option to enhance oil recovery while simultaneously contributing to carbon storage. Conventional core tests provide critical insights but still leave ambiguous transport mechanisms due to the limitation of real-time visualization. This study aims to directly observe the multiphase flow behaviors and phase change in CO2 injection at pore-scale using microfluidics. Our all-in-one chip design provides a universal platform to reproduce various CO2 injection strategies in the formation with permeability contrast, including flooding and huff-n-puff processes, and integrated a rapid measurement of minimum miscibility pressure (MMP). Miscible injection eliminates the capillary force in immiscible scenario, and promotes stable film-wise displacement with a higher recovery rate and an attenuated heterogeneity impact. We find that effective huff-n-puff operations require a sufficient gas concentration to generate bubbles and an adequate pressure gradient to push the dissolved gas displacement, which supports the importance of high depressurization rate from both physical phenomenon and inherent mechanism. Huff-n-puff re-energizes the reservoir after immiscible flooding through deep gas-oil interactions and induces a considerable growth in cumulative recovery. These micromodel results can significantly improve our fundamental understanding on detailed multiphase transport phenomena in CO2 injection and help to optimize implementation schemes.

Direct Measurement of Minimum Miscibility Pressure of Decane and CO2 in Nanoconfined Channels.

Determining gas and oil minimum miscibility pressure (MMP) plays a vital role in the enhanced oil recovery. Injecting gases above the MMP into oil reservoirs leads to a relatively high oil recovery ratio. For conventional reservoirs, the fluid bulk MMP is measured by lab techniques such as the rising bubble approach. However, for the increasingly important tight and shale reservoirs, oil is confined in nanoscale pores. Nanoscopic MMP remains largely unknown from experiments and relies heavily on theoretical predictions. To close this gap, we developed a nanofluidic device to determine the MMP down to 50 nm by measuring the fluorescence intensity change in a nanoconfined channel. CO2 and decane are used as the working fluids, with 1% fluorescent dye for characterization. At the isothermal condition, the fluorescence intensity in decane reduces with the injecting CO2 pressure increasing, and the maximum fluorescence intensity reduction at certain CO2 pressure indicates the MMP being reached. We measured and compared CO2 and decane MMP at the bulk scale (5 μm) and nanoscale (50 nm). The experimental results align well with literature data and theoretical predictions. Importantly, our nanofluidic approach provides a promising strategy to determine the nanoscopic fluid MMP and is readily applicable in assisting the enhanced tight/shale oil recovery.

Experimental Investigation of Asphaltene Content Effect on Crude Oil/CO2 Minimum Miscibility Pressure

Minimum Miscibility Pressure (MMP) is regarded as one of the foremost parameters required to be measured in a CO2 injection process. Therefore, a reasonable approximation of the MMP can be useful for better development of injection conditions as well as planning surface facilities. In this study, the impact of asphaltene content ranging from 3.84 % to 16 % on CO2/heavy oil MMP is evaluated. In this respect, slim tube miscibility and Vanishing Interfacial Tension (VIT) tests are used. Regarding the VIT test, the Interfacial Tension (IFT) is measured by means of two methods including pendant drop and capillary apparatuses, and thereafter the MMP measurement error between slim tube and VIT methods are calculated. Based on the results, by increasing the asphaltene content, the measured MMP by slim tube method increases linearly while that by VIT follows no clear trend. The results also indicate that there is an asphaltene content range within which the MMP error between slim tube and VIT tests is minimized. IFT measurement by pendant drop and Capillary Glass Tube (CGT) methods show that by increasing asphaltene content up to 10.15 %, IFT declines, whereas for further increase in content, IFT increases because of the irregular dispersion of asphaltene in oil droplets.

CO2 miscible flooding for Aswad Oil Field

The current renewed interest on research and development of EOR processes and their oilfield implementation would allow targeting significant volumes of oil accumulations that have been left behind in mature reservoirs after primary and secondary oil recovery operations.During the life of a producing oil field, several production stages are encountered. Initially, when a field is brought into production, oil flows naturally to the surface due to existing reservoir pressure in the primary phase. As reservoir pressure drops, water is typically injected to boost the pressure to displace the oil in the secondary phase. Lastly, the remaining oil can be recovered by a variety of means such as CO2 injection, natural gas miscible injection, and steam recovery in the final tertiary or enhanced oil recovery (EOR) phase.The main parameter for determination of the possibilities to enhance oil recovery by e.g. CO2 injection into a specific oil field is the measurement of Minimum Miscibility Pressure (MMP). This pressure is the lowest pressure for which a gas can obtain miscibility through a multi contact process with a given oil reservoir at the reservoir temperature. The oil formation to which the process is applied must be operated at or above the MMP. And we obtained by using PVTi software.The objective of this paper is to check if the Aswad field is suited for the application of CO2 miscible flooding and to see how much the recovery factor will increase after applying this EOR technique and to obtain the best WAG ratio and injection rate.

Experimental Determination of Minimum Miscibility Pressure

Minimum miscibility pressure (MMP) plays a great role in determining the displacement efficiency of different gas injection processes. Experimental techniques for MMP determination include industrially recommended slim tube, vanishing interfacial tension (VIT) and rising bubble apparatus (RBA). In this paper, MMP measurement study using slim tube and VIT experimental techniques for two different crude oil samples (M and N) both in live and stock tank oil forms is being presented. VIT measured MMP values for both’M’ and’N’ live crude oils were close to slim tube determined MMP values with 6.4 and 5% deviation respectively. Whereas for both oil samples in stock tank oil form, VIT measured MMP showed a higher unacceptable deviation from slim tube determined MMP. This higher difference appears to be related to high stabilized crude oil heavier fraction and lack of multiple contacts miscibility. None of the different nine deployed crude oil – CO2 MMP computing correlations could result in reliable MMP, close to slim tube determined MMP. Since VIT determined MMP values for both considered live crude oils are in close match with slim tube determined MMP values, it confirms reliable, reproducible, rapid and cheap alternative for live crude oil MMP determination. Whereas VIT MMP determination for stock tank oil case needed further investigation about stabilization / destabilization mechanism of oil heavier ends and multiple contacts miscibility development issues.

Fast fluorescence-based microfluidic method for measuring minimum miscibility pressure of CO2 in crude oils.

Carbon capture, storage, and utilization has emerged as an essential technology for near-term CO2 emission control. The largest CO2 projects globally combine storage and oil recovery. The efficiency of this process relies critically on the miscibility of CO2 in crude oils at reservoir conditions. We present a microfluidic approach to quantify the minimum miscibility pressure (MMP) that leverages the inherent fluorescence of crude oils, is faster than conventional technologies, and provides quantitative, operator-independent measurements. To validate the approach, synthetic oil mixtures of known composition (pentane, hexadecane) are tested and MMP values are compared to reported values. Results differ by less than 0.5 MPa on average, in contrast to comparison between conventional methods with variations on the order of 1-2 MPa. In terms of speed, a pressure scan for a single MMP measurement required less than 30 min (with potential to be sub-10 min), in stark contrast to days or weeks with existing approaches. The method is applied to determine the MMP for Pennsylvania, West Texas, and Saudi crudes. Importantly, our fluorescence-based approach enables rapid, automated, operator-independent measurement of MMP as needed to inform the world's largest CO2 projects.

A new correlation for calculating carbon dioxide minimum miscibility pressure based on multi-gene genetic programming

Miscible gas injection is one of the most efficient enhanced oil recovery (EOR) methods in petroleum industry. Minimum miscibility pressure (MMP) is a key parameter in any gas injection design project. Experimental Measurement of MMP is a costly and time-consuming method; so searching for a quick, not expensive and reliable method to determine gas-oil MMP is inevitable. This paper Present a fast and vigorous method using a new approach based on multi-gene genetic programming (MGGP) to determine carbon dioxide minimum miscibility pressure (CO2 MMP) for carbon dioxide injection processes. Then, new correlations for MMP calculation of both pure and impure CO2 streams using the MGGP, have been developed. Consequently, the MGGP models have been validated and compared with the other conventional model results, to evaluate different techniques. It was founded that the new developed correlations predict accurate values of CO2 MMP compare with the experimental slim-tube CO2 MMP test results, with the lowest average relative and absolute error and also higher correlation coefficient among all evaluated CO2 MMP correlation results.

Effect of CO2 Concentration in Injecting Gas on Minimum Miscibility Pressure: Compositional Model and Experimental Study

For technical and economic success of miscible gas injection projects, an accurate laboratory measurement of Minimum Miscibility Pressure (MMP) at reservoir conditions is essential. On the other hand, compositional reservoir simulator is a useful tool in gas injection studies and prediction of MMP. The main goal of this paper is to describe a procedure to generate a three phase sequential type of compositional reservoir simulator. The solution method is completely addressed. A compositional thermodynamic program for equilibrium calculation, and pseudo-component determination was developed. Another purpose of this study is to prepare an experimental setup for investigating the effect of CO2 concentration in injecting gas on oil recovery and MMP.Some displacement tests using slim tube apparatus were performed and recoveries and MMPs were measured. Finally, experimental results were compared with the model predictions. A good agreement was achieved between the experimental data and model predictions.

Laboratory Investigation of Weyburn CO2 Miscible Flooding

Abstract Weyburn reservoir, located in southeast Saskatchewan and operated by PanCanadian Petroleum Ltd., has reached its economic limit of production by waterflooding. The reservoir is a target for tertiary CO2 miscible flooding to enhance oil recovery and extend its production life. A comprehensive study has been conducted by the Saskatchewan Research Council and PanCanadian to assess the suitability of the process for Weyburn. This paper presents a technical evaluation of CO2 near-miscible injection for Weyburn reservoir. This is based on laboratory studies conducted with three Weyburn oils collected from different regions of the reservoir. These studies included:measurement of minimum miscibility pressure for the reconstituted reservoir fluids for pure and impure CO2,determination of PVT properties for reservoir fluid-CO2 mixtures, andassessment of recovery behavior from uniquely designed laboratory core-flood tests representing the permeability contrast of the reservoir. The studies indicated that the CO2 minimum miscibility pressure for the Weyburn reservoir oils varied from about 11.5 to 14.5 MPa, indicating suitability for CO2 miscible flooding. PVT data generated for the three Weyburn reservoir fluid-CO2 mixtures showed that viscosity reduction and oil swelling by CO2 also contributed to oil recovery. A slight manipulation of the measured PVT properties of the mixtures made it possible to obtain single property curves for the three Weyburn oils. This feature can be used to estimate the PVT behavior for any Weyburn oil from the reservoir. Core-flood studies showed that CO2 injected into the Vuggy zone could rise to the upper Marly zone and help enhance oil recovery. A separate simulation and modelling study conducted by PanCanadian Petroleum Ltd. satisfactorily matched the experimental PVT properties, MMP values and recovery mechanism suggested by the core-flood behaviour. Introduction The total oil reserves of Saskatchewan are estimated at over 3 billion m3 of initial oil-in-place (IOIP). The light and medium oil reserves contribute approximately 1.6 billion m3 IOIP(1). Over 10﹪ of the light and medium reserves, or 178 million m3 IOIP, are held in Weyburn reservoir. The Weyburn field is located approximately 130 km southeast of Regina in Saskatchewan and covers over 180 km2 of production area. The field was discovered in 1955 and PanCanadian Petroleum (PCP) Ltd. is the major operator. It has over 627 producing wells and 162 water injection wells on approximately 24 ha spacing(2). The oil production from the Weyburn field comes from Midale beds of the Mississippian Charles Formation in the Williston Basin at a depth of 1,310 to 1,500 m. The field was produced by primary depletion for about nine years until 1964. Waterflood was started thereafter using a nine-spot pattern. In 1985, to optimize the waterflood performance, both horizontal and vertical infill drilling programs were initiated. The combined oil recovery by primary and secondary production was approximately 28﹪ IOIP by 1994. Waterflooding has almost reached its economic limit for the Weyburn reservoir. The ultimate conventional recovery is expected to be 31﹪ IOIP, leaving a large target for tertiary recovery techniques(3). A similar situation exists for the majority of Saskatchewan's light and medium reservoirs(1,4).

A Comparative Investigation of Minimum Miscibility Pressure Correlations For Enhanced Oil Recovery

Abstract Multiple contact miscible floods involving the injection of relatively inexpensive gases into oil reservoirs represent one of the most cost effective enhanced oil recovery processes currently available. The experimental displacement procedures available for determining the optimal flood pressure, referred to as the minimum miscibility pressure (MMP), are both costly and time consuming. Hence, the use of a correlation proven reliable over a large range of conditions would likely be considered acceptable for the purposes of preliminary screening studies. This paper presents an evaluation of 15 rich gas, lean gas, and nitrogen MMP correlations published in the literature. Each method was developed using experimental data, equation-of-state (EOS) predictions, or a combination of the two. The accuracy of each correlation was evaluated by comparing predicted versus measured MMP's using a data base consisting predominantly of experimental results published in the literature. The most reliable MMP correlations were all found to have a common EOS developmental basis. These results support the applicability of EOS-based methods for accurate MMP predictions. Introduction The injection gases most commonly used for enhanced oil recovery processes are generally not miscible upon first contact with the reservoir fluids that they are displacing. However, under suitable reservoir pressure and temperature conditions, miscibility may gradually be developed between some injection-gas/reservoir-oil combinations by a mass transfer of components between the gaseous and liquid phases. Miscibility generated in such a manner is commonly referred to as multiple contact (dynamic) miscibility, and has been well described in the literature(1). The vaporizing gas drive (VGD) and the condensing gas drive (CGD) are the mechanisms through which dynamic miscibility is generally explained. Miscibility develops at the flood front during VGD processes, which are commonly referred to as lean gas (LG) drives. Dynamic miscibility in nitrogen (N2) floods similarly occurs through the VGD mechanism. During CGD processes, generally referred to as rich gas (RG) drives, miscibility develops at the injection point. Recent research has indicated, however, that miscibility in some RG drives may actually develop through a liquid extraction drive (LED) process(2,3). Similar to VGD's, miscibility develops at the flood front during a LED. An optimum displacement pressure exists for a dynamic miscible flood, commonly referred to as the minimum miscibility pressure (MMP). The object of this study is to evaluate available RG, LG, and N2 MMP correlations using a data base consisting predominantly of experimental MMP results published in the literature. Measurement and Prediction of MMP's The MMP for gas/oil mixtures has traditionally been measured by performing slim tube displacement experiments(1). These experiments involve constant temperature displacement of a live oil from the slim tube by an injection gas. The MMP has typically been accepted as the pressure at which a practical maximum recovery efficiency is observed following a series of displacements. MMP values have also been measured for many gas/oil pairs using the Rising Bubble Apparatus (RBA)(4), where a small bubble of gas is injected at the base of a column of live oil.

Rapid Measurement of Minimum Miscibility Pressure With the Rising-Bubble Apparatus

Summary The minimum miscibility pressure (MMP) for a gas/oil pair can be measured within 1 hour with the rising-bubble apparatus (RBA). Development of miscibility between a gas bubble and an oil can be observed visually. The measurements of the MMP with the RBA compare favorably with those based on slim-tube experiments and predictions from phase-behavior studies.