The Effect of Partial Molar Volume on Water-shielded Oil Recovery Time by Miscible Gas Injection

Author(s):  
S. Mirazimi ◽  
B. Rostami ◽  
M. Ghazanfari
2021 ◽  
Author(s):  
Gang Yang ◽  
Xiaoli Li

Abstract Minimum miscibility pressure (MMP), as a key parameter for the miscible gas injection enhanced oil recovery (EOR) in unconventional reservoirs, is affected by the dominance of nanoscale pores. The objective of this work is to investigate the impact of nanoscale confinement on MMP of CO2/hydrocarbon systems and to compare the accuracy of different theoretical approaches in calculating MMP of confined fluid systems. A modified PR EOS applicable for confined fluid characterization is applied to perform the EOS simulation of the vanishing interfacial tension (VIT) experiments. The MMP of multiple CO2/hydrocarbon systems at different pore sizes are obtained via the VIT simulations. Meanwhile, the multiple mixing cell (MMC) algorithm coupled with the same modified PR EOS is applied to compute the MMP for the same fluid systems. Comparison of these results to the experimental values recognize that the MMC approach has higher accuracy in determining the MMP of confined fluid systems. Moreover, nanoscale confinement results in the drastic suppression of MMP and the suppression rate increases with decreasing pore size. The drastic suppression of MMP is highly favorable for the miscible gas injection EOR in unconventional reservoirs.


2021 ◽  
Author(s):  
Sergey Anatolevich Vershinin ◽  
Alexander Nikolaevich Blyablyas ◽  
Dmitriy Aleksandrovich Golovanov ◽  
Artem Vitalievich Penigin ◽  
Nikolay Grigorievich Glavnov

Abstract The problem of associated petroleum gas utilization is especially urgent for fields located far from infrastructure facilities for raw gas transportation and treatment. For such fields, alternative methods of gas utilization, especially gas re-injection, are becoming relevant. The re-injection options include: injection into underground reservoir for storage (if there are reservoirs suitable for injection near the field), injection into a gas cap, if any, or injection into a productive reservoir. The latter method allows, along with solving the problem of gas disposal, to increase oil recovery. This study describes an example of miscible gas injection into the reservoir at the Chatylkinskoye field, the infrastructure assumptions which make this option a better one versus a selling option, and the features of a gas treatment and injection process.


Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Dangke Ge ◽  
Haiying Cheng ◽  
Mingjun Cai ◽  
Yang Zhang ◽  
Peng Dong

Gas injection processes are among the effective methods for enhanced oil recovery. Miscible and/or near miscible gas injection processes are among the most widely used enhanced oil recovery techniques. The successful design and implementation of a miscible gas injection project are dependent upon the accurate determination of minimum miscibility pressure (MMP), the pressure above which the displacement process becomes multiple-contact miscible. This paper presents a method to get the characteristic curve of multiple-contact. The curve can illustrate the character in the miscible and/or near miscible gas injection processes. Based on the curve, we suggest a new model to make an accurate prediction for CO2-oil MMP. Unlike the method of characteristic (MOC) theory and the mixing-cell method, which have to find the key tie lines, our method removes the need to locate the key tie lines that in many cases is hard to find a unique set. Moreover, unlike the traditional correlation, our method considers the influence of multiple-contact. The new model combines the multiple-contact process with the main factors (reservoir temperature, oil composition) affecting CO2-oil MMP. This makes it is more practical than the MOC and mixing-cell method, and more accurate than traditional correlation. The method proposed in this paper is used to predict CO2-oil MMP of 5 samples of crude oil in China. The samples come from different oil fields, and the injected gas is pure CO2. The prediction results show that, compared with the slim-tube experiment method, the prediction error of this method for CO2-oil MMP is within 2%.


2011 ◽  
Vol 361-363 ◽  
pp. 516-519
Author(s):  
Ju Li ◽  
Xin Wei Liao ◽  
Su Kun

Miscible and/or near miscible gas injection processes are among the most widely used enhanced oil recovery techniques. The successful design and implementation of a miscible gas injection project is dependent upon the accurate determination of minimum miscible pressure (MMP), the pressure above which the displacement process becomes multi-contact miscible. Analytical methods, which are inexpensive and quick to use, have been developed to estimate MMP for complex fluid characterizations. However, many problems still existed in the analytical calculation, which will lead to the failure of calculation, or wrong result. This paper shows how the initial tie line could be calculated when the component of injection gas doesn’t included in the crude oil. And moreover, how to get a complete set of initial value for the equations of crossover tie lines, and the influence of EOS for the result of key tie lines is analyzed simultaneously.


SPE Journal ◽  
2018 ◽  
Vol 23 (06) ◽  
pp. 2376-2393 ◽  
Author(s):  
Olav Møyner ◽  
Hamdi A. Tchelepi

Summary Compositional simulation is necessary for a wide variety of reservoir-simulation applications, and it is especially valuable for accurate modeling of near-miscible gas injection for enhanced oil recovery. Because the nonlinear behavior of gas injection is sensitive to the resolution of the simulation grid used, it is important to use a fine grid to accurately resolve the compositional and saturation gradients. Compositional simulation of highly detailed reservoir models entails the use of small timesteps and large, poorly conditioned linear systems. The high computational cost of solving such systems renders field-scale simulations practically unfeasible. The coupling of the flow and transport to the phase-equilibrium calculations adds to the challenge. This is especially the case for near-miscible gas injection, in which the phase state and the phase compositions are very strong functions of space and time. We present a multiscale solver for compositional displacements with three-phase fluid flow. The thermodynamic phase behavior is described by general nonlinear cubic equations of state (EOS). The fully implicit (FI) natural-variables formulation is used as the basis to derive a sequential implicit (SI) solution strategy, whereby the pressure field is decoupled from the multicomponent transport. The SI scheme is mass conservative without the need to iterate between the pressure and transport equations during the timestep. This conservation property allows the errors caused by fixing the total-velocity field between the pressure- and transport-updating steps to be represented as a volume error. The method computes approximate pressure solutions—within a prescribed residual tolerance—that yield conservative fluxes on the computational grid of interest (fine, coarse, or intermediate). We use basis functions computed using restricted smoothing to allow for generally unstructured grids. The new method is verified against existing research and commercial compositional simulators using a simple conceptual test case and also using more-complex cases represented on both unstructured and corner-point grids with strong heterogeneity, faults, and pinched-out and eroded cells. The SI method and the implementation described here represent the first demonstrated multiscale method applicable to general compositional problems with complexity relevant for industrial-reservoir simulation.


2007 ◽  
Vol 72 (3) ◽  
pp. 351-367 ◽  
Author(s):  
Mehran Sohrabi ◽  
Ali Danesh ◽  
Dabir H. Tehrani ◽  
Mahmoud Jamiolahmady

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