Improved Fluids Characterization Model During Gas Huff-n-Puff EOR Processes in Unconventional Reservoirs

2021 ◽  
Author(s):  
Gang Yang ◽  
Xiaoli Li
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Fluid Model ◽  
Geometric Constraints ◽  
Confinement Effect ◽  
Recovery Factor ◽  
Unconventional Reservoirs ◽  
Compositional Simulation ◽  
Compositional Model ◽  
Characterization Model

Abstract Despite the great potential of unconventional hydrocarbons, the primary recovery factor from such reservoirs remain low. The gas-injection enhanced oil recovery (EOR) has been proved to be a promising approach by both laboratory and simulation studies. However, the fluid model for characterizing gas and oil in nanoscale pores has not been well understood and developed. Erroneous results can be generated if the bulk fluids model is applied, resulting in a large uncertainty for the numerical simulations. The objective of this work is to propose an improved fluids characterization model tailored for the compositional simulation of gas huff-n-puff in unconventional reservoirs. The Peng-Robinson equation of state (PR EOS) is used as the basic thermodynamic model in this work. Both the attraction parameter and the co-volume parameter in the PR EOS are simultaneously modified for the first time to reflect the effect of molecule-wall interaction and geometric constraints. The collected experimental data are used for validating the model. The newly generated PVT data are imported into the compositional model to numerically simulate the gas huff-n-puff process in the Middle Bakken formation to investigate the influence of modified fluid property on the production and ultimate recovery. The improved fluids characterization model is validated applicable to calculate the confined properties of reservoir fluids. It is demonstrated that the phase envelope of the confined reservoir fluids tends to shrink. At reservoir temperature, the bubble-point pressure of the Middle Bakken oil is reduced by 17.32% with consideration of the confinement effect. Such a significant suppression represents a late occurrence of the gas evaporation, which implies a potentially higher production of the shale oil reservoir. Compositional simulation predicts that the enhanced oil recovery efficiency of CO2 huff-n-puff is unsatisfactory for the specific well in this work, which is also demonstrated in the field pilot test. However, the confinement effect results in a 1.14% elevation of the oil recovery factor in 10 years production. This work not only deepens our understanding of the confinement effect on phase behavior characterization and also shed light on the computation of the thermodynamic properties of hydrocarbons in nanopores. The results also provide practical instructions for the EOR development of unconventional reservoirs.

scholarly journals Optimization of triple-alternating-gas (TAG) injection technique for enhanced oil recovery in tight oil reservoirs

2021 ◽  
Author(s):  
Mvomo Ndzinga Edouard ◽  
Pingchuan Dong ◽  
Chinedu J. Okere ◽  
Luc Y. Nkok ◽  
Abakar Y. Adoum ◽  
...  
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Gas Injection ◽  
Oil Reservoirs ◽  
Recovery Factor ◽  
Injection Technique ◽  
Tight Oil ◽  
Compositional Model ◽  
Injection Scheme ◽  
Tight Oil Reservoirs

AbstractAfter single-gas (SG) injection operations in tight oil reservoirs, a significant amount of oil is still unrecovered. To increase productivity, several sequencing gas injection techniques have been utilized. Given the scarcity of research on multiple-gas alternating injection schemes, this study propose an optimized triple-alternating-gas (TAG) injection for improved oil recovery. The performance of the TAG process was demonstrated through numerical simulations and comparative analysis. First, a reservoir compositional model is developed to establish the properties and composition of the tight oil reservoir; then, a suitable combination for the SG, double alternating gas (DAG), and TAG was selected via a comparative simulation process. Second, the TAG process was optimized and the best case parameters were derived. Finally, based on the oil recovery factors and sweep efficiencies, a comparative simulation for SG, DAG, and TAG was performed and the mechanisms explained. The following findings were made: (1) The DAG and TAG provided a higher recovery factor than the SG injection and based on recovery factor and economic advantages, CO2 + CH4 + H2S was the best choice for the TAG process. (2) The results of the sensitivity analysis showed that the critical optimization factors for a TAG injection scheme are the injection and the production pressures. (3) After optimization, the recovery factor and sweep efficiency of the TAG injection scheme were the best. This study promotes the understanding of multiple-gas injection enhanced oil recovery (EOR) and serves as a guide to field design of gas EOR techniques.

Evaluation of CO2 enhanced oil recovery in unconventional reservoirs: Experimental parametric study in the Bakken

Fuel ◽  
2022 ◽  
Vol 312 ◽  
pp. 122941
Author(s):  
Nidhal Badrouchi ◽  
Hui Pu ◽  
Steven Smith ◽  
Foued Badrouchi
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Parametric Study ◽  
Unconventional Reservoirs

Application of CFD to evaluate the pore morphology effect on nanofluid flooding for enhanced oil recovery

RSC Advances ◽  
2015 ◽  
Vol 5 (37) ◽  
pp. 28938-28949 ◽  
Author(s):  
Reza Gharibshahi ◽  
Arezou Jafari ◽  
Ali Haghtalab ◽  
Mohammad Saber Karambeigi
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Recovery Factor ◽  
Pore Morphology ◽  
Morphology Effect ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

In this study a computational fluid dynamics (CFD) method has been developed to simulate the effect of pore morphology and its distribution in a 2D micromodel on the enhanced oil recovery factor of nanofluid flooding.

scholarly journals The efficiency of gas injection into low-permeability multilayer hydrocarbon reservoirs

2021 ◽  
Vol 3 (10) ◽  
pp. 100-108
Author(s):  
Sudad H AL-Obaidi ◽  
Miel Hofmann ◽  
Falah H. Khalaf ◽  
Hiba H. Alwan
Keyword(s):  
Hydraulic Fracturing ◽  
Oil Recovery ◽  
Gas Injection ◽  
Oil Production ◽  
Recovery Factor ◽  
Low Permeability ◽  
Compositional Model ◽  
Multistage Hydraulic Fracturing ◽  
Low Permeability Reservoirs ◽  
Working Agent

The efficiency of gas injection for developing terrigenous deposits within a multilayer producing object is investigated in this article. According to the results of measurements of the 3D hydrodynamic compositional model, an assessment of the oil recovery factor was made. In the studied conditions, re-injection of the associated gas was found to be the most technologically efficient working agent. The factors contributing to the inefficacy of traditional methods of stimulating oil production such as multistage hydraulic fracturing when used to develop low-permeability reservoirs have been analyzed. The factors contributing to the inefficiency of traditional oil-production stimulation methods, such as multistage hydraulic fracturing, have been analysed when they are applied to low-permeability reservoirs. The use of a gas of various compositions is found to be more effective as a working agent for reservoirs with permeability less than 0.005 µm2. Ultimately, the selection of an agent for injection into the reservoir should be driven by the criteria that allow assessing the applicability of the method under specific geological and physical conditions. In multilayer production objects, gas injection efficiency is influenced by a number of factors, in addition to displacement, including the ratio of gas volumes, the degree to which pressure is maintained in each reservoir, as well as how the well is operated. With the increase in production rate from 60 to 90 m3 / day during the re-injection of produced hydrocarbon gas, this study found that the oil recovery factor increased from 0.190 to 0.229. The further increase in flow rate to 150 m3 / day, however, led to a faster gas breakthrough, a decrease in the amount of oil produced, and a decrease in the oil recovery factor to 0.19 Based on the results of the research, methods for stimulating the formation of low-permeability reservoirs were ranked based on their efficacy.

CO2-Based Enhanced Oil Recovery from Unconventional Reservoirs: A Case Study of the Bakken Formation

2014 ◽  
Author(s):  
G. Liu ◽  
J.A. Sorensen ◽  
J.R. Braunberger ◽  
R. Klenner ◽  
J. Ge ◽  
...  
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Unconventional Reservoirs ◽  
Bakken Formation

A Literature Review of CO2, Natural Gas, and Water-Based Fluids for Enhanced Oil Recovery in Unconventional Reservoirs

2020 ◽  
Vol 34 (5) ◽  
pp. 5331-5380 ◽  
Author(s):  
Lauren C. Burrows ◽  
Foad Haeri ◽  
Patricia Cvetic ◽  
Sean Sanguinito ◽  
Fan Shi ◽  
...  
Keyword(s):  
Natural Gas ◽  
Literature Review ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Unconventional Reservoirs ◽  
Water Based

scholarly journals Effect of Emulsification on Enhanced Oil Recovery during Surfactant/Polymer Flooding in the Homogeneous and Heterogeneous Porous Media

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Xiaoyan Wang ◽  
Jie Zhang ◽  
Guangyu Yuan ◽  
Wei Wang ◽  
Yanbin Liang ◽  
...  
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
High Water ◽  
Heterogeneous Porous Media ◽  
Recovery Factor ◽  
Water Flooding ◽  
Core Flooding ◽  
Positive Role ◽  
High Water Cut ◽  
Water Cut

Surfactant polymer (SP) flooding has become an important enhanced oil recovery (EOR) technique for the high-water cut mature oilfield. Emulsification in the SP flooding process is regarded as a powerful mark for the successful application of SP flooding in the filed scale. People believe emulsification plays a positive role in EOR. This paper uses one-dimensional homogenous core flooding experiments and parallel core flooding experiments to examine the effect of emulsification on the oil recoveries in the SP flooding process. 0.3 pore volume (PV) of emulsions which are prepared using ultralow interface intension (IFT) SP solution and crude oil with stirring method was injected into core models to mimic the emulsification process in SP flooding, followed by 0.35 PV of SP flooding to flood emulsions and remaining oil. The other experiment was preformed 0.65 PV of SP flooding as a contrast. We found SP flooding can obviously enhance oil recovery factor by 25% after water flooding in both homogeneous and heterogeneous cores. Compared to SP flooding, emulsification can contribute an additional recovery factor of 3.8% in parallel core flooding experiments. But there is no difference on recoveries in homogenous core flooding experiments. It indicates that the role of emulsification during SP flooding will be more significant for oil recoveries in a heterogeneous reservoir rather than a homogeneous reservoir.

scholarly journals How Ultrasonic-Assisted CO2 EOR to Unlock Oils From Unconventional Reservoirs?

2021 ◽  
Author(s):  
Hengli Wang ◽  
Leng Tian ◽  
Kaiqiang Zhang ◽  
Zongke Liu ◽  
Can Huang ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Carbon Number ◽  
Recovery Process ◽  
Recovery Factor ◽  
Unconventional Reservoirs ◽  
Geological Storage ◽  
Tube Test ◽  
Ultrasonic Assisted ◽  
Actual Field ◽  
Oil Gas

CO2 enhanced oil recovery (EOR) has been proven its capability to explore the unconventional tight oil reservoirs and potential for geological carbon storage. Meanwhile, the extremely low permeability pores exaggerate the difficulty CO2 EOR and geological storage processing in the actual field. This paper initiates the ultrasonic-assisted approach to facilitate the oil-gas miscibility development and finally contribute to unlock more tight oils. First, the physical properties of crude oil with and without ultrasonic treatments were experimentally analysed through gas chromatography (GC), Fourier-transform infrared spectroscopy (FTIR) and viscometer. Second, the oil-gas minimum miscibility pressures (MMPs) were measured from the slim-tube test and the miscibility developments with and without ultrasonic treatments were interpreted from the mixing-cell method. Third, the nuclear-magnetic resonance (NMR) assisted coreflood tests were conducted to physically model the recovery process in porous media and directly obtain the recovery factor. Basically, the ultrasonic treatment (40KHz and 200W for 8 hours) was found to substantially change the oil properties, with viscosity (at 60°C) reduced from 4.1 to 2.8mPa·s, contents of resin and asphaltene decreased from 27.94% and 6.03% to 14.2% and 3.79%, respectively. The FTIR spectrum shows the unsaturated C-H bond, C-O bond and C≡C bond in macromolecules were broken from ultrasonic, which caused the macromolecules (e.g., resin and asphaltenes) to be decomposed into smaller carbon-number molecules. Accordingly, the MMP was determined to be reduced from 15.8 to 14.9MPa from the slim-tube test and the oil recovery factor increased by over 10%. This study reveals the mechanisms of ultrasonic-assisted CO2 miscible EOR in producing tight oils.

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