Development of Depleted Oil Reservoirs for Simultaneous Gas Injection for Underground Natural Gas Storage and Enhanced Oil Recovery in Nigeria

2016 ◽  
Author(s):  
C. I. C. Anyadiegwu
Keyword(s):  
Natural Gas ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Gas Injection ◽  
Gas Storage ◽  
Oil Reservoirs ◽  
Natural Gas Storage

Risk Assessment and Enhanced Oil Recovery Effect of Gravity Assisted Oxygen-Reduced Air Flooding

2021 ◽  
Author(s):  
Lijuan Huang ◽  
Zongfa Li ◽  
Shaoran Ren ◽  
Yanming Liu
Keyword(s):  
Natural Gas ◽  
Oil Recovery ◽  
Gas Injection ◽  
Oil Production ◽  
Air Injection ◽  
Oil Reservoirs ◽  
Displacement Efficiency ◽  
Risk Area ◽  
Recovery Method ◽  
High Risk Area

Abstract The technology of air injection has been widely used in the second and tertiary recovery in oilfields. However, due to the injected air and natural gas will explode, the safety of the gas injection technology has attracted much attention. Gravity assisted oxygen-reduced air flooding is a new method that eliminates explosion risks and improves oil recovery in large-dip oil reservoirs or thick oil layers. The explosion limit data of different components of natural gas under high pressure were obtained through explosion experiments, which verified the suppression effect of oxygen-reduced air on explosions. The influence of natural gas composition and concentration on explosion limits was also investigated. In addition, a rotatable displacement device was used to study the feasibility of gravity assisted oxygen-reduced air injection for improving the heavy oil reservoirs recovery. Under pressure and temperature conditions of 20MPa and 371K, the sand-filled gravity flooding experiments with different dip angles were carried out using oxygen-reduced air with an oxygen content of 8%. The results show that with the increase of the reservoir dip, the pore volume of the injected fluid at the gas channeling point, the efficient development time of gas injection, and the final displacement efficiency of gas injection development all increase through gravity stabilization caused by gravity differentiation. In the presence of a dip angle, the cumulative oil production before the gas breakthrough point exceeded 80% of the oil production during the entire production process, indicating that gravity assisted oxygen-reduced air flooding is an effective and safe improving oil recovery method. Finally, the explosion risk of each link of the air injection process is analyzed, and the high-risk area and the low-risk area are determined.

Unsteady-State Distributions of Fluid Compositions in Two-Phase Oil Reservoirs Undergoing Gas Injection

1967 ◽  
Vol 7 (01) ◽  
pp. 61-74 ◽  
Author(s):  
Robert C. McFarlane ◽  
T.D. Mueller ◽  
F.G. Miller
Keyword(s):  
Oil Recovery ◽  
High Speed ◽  
Gas Injection ◽  
Gas Storage ◽  
Oil Reservoirs ◽  
Oil Reservoir ◽  
Two Phase ◽  
Secondary Recovery ◽  
Compositional Effects ◽  
Gas Cycling

Abstract During the process of gas storage in pressure-depleted oil reservoirs, it has been observed that in some instances additional liquid oil is recovered and that the composition of the storage gas is materially altered. A mathematical study was made of the dynamic behavior of such a depleted oil reservoir undergoing gas injection. The important variable considered in this study, not included in previously published work, was that of compositional effects on the phase behavior of two-phase flow. Pressure, saturation and component composition profiles were developed for a linear, horizontal and homogeneous porous medium containing oil and gas but undergoing dry gas injection. Special new techniques were developed to overcome the problems of numerical smoothing which arise in the solution of the equations representing such systems. The method of solution includes the development of partial differential equations describing the behavior of the system, representing these equations by finite difference approximations, making certain simplifying assumptions and, finally, applying methods of numerical analysis with the aid of a high-speed digital computer. In an example calculation, results using the mathematical model are compared with field observations made on a gas storage project in Clay County, Tex. This field project involved a depleted oil reservoir used' for gas storage and gas cycling purposes. As a result of these processes, the reservoir yielded substantial amounts of secondary oil, both in the form of stock tank oil and as vaporized products in the produced gas. The methods derived in this study may be applied to a variety of oil reservoir problems which are dependent on compositional effects. INTRODUCTION In recent years the number of oil reservoirs being used for gas storage purposes has increased greatly, and there has been at least one published account of additional oil recovery resulting from gas cycling a depleted oil reservoir after repressuring with dry gas for storage purposes. Additional oil recovery from oil reservoirs resulting from gas storage operations could become an important secondary recovery process. This is especially true since the use of natural gas in large metropolitan areas continues to increase and more gas storage volume near these areas is needed. These facts provided the motivation for the work reported here. This paper reports on a study of the inter-relations of composition, saturation and pressure changes which occur when hydrocarbon gas is injected into an oil reservoir system. From an understanding of the process, prediction methods may be developed for use in forecasting the secondary recovery products from gas storage operations in oil reservoirs and, consequently, .the economics of such projects can be developed.

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.

scholarly journals Gas Turbine Driven Reciprocating Compressors for a Natural Gas Storage Plant

1988 ◽  
Author(s):  
Martin Urban ◽  
Hubert Andrée
Keyword(s):  
Natural Gas ◽  
Gas Injection ◽  
Gas Storage ◽  
West Germany ◽  
Storage Facility ◽  
Working Capacity ◽  
Natural Gas Storage ◽  
Flow Rates ◽  
Expansion Phase ◽  
Wide Range

A major expansion phase is underway at the Ruhrgas natural gas storage plant at Epe on the border between West Germany and the Netherlands. The plant already has 8 caverns with a total working capacity of approx. 350 × 106 m3 (n). 28 caverns are to be added, to bring the total to approx. 1.0 × 109 m3 (n). In view of the increase in capacity, it was necessary to raise the power installed for driving gas compressors from the existing figure of approx. 3,000 kW to a total of 12,000 kW in phase II. A minimum of 2 units were required for this figure of 9,000 kW. Epe is already the second largest natural gas storage facility in West Germany and is designed to store both low BTU and high BTU natural gas. The facilities are operated at a wide range of pressures and flow rates. The new compressor units will be used only for gas injection at well head pressures of up to 200 bar.

scholarly journals Experimental Studies of Immiscible High-Nitrogen Natural Gas WAG Injection Efficiency in Mixed-Wet Carbonate Reservoir

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2346
Author(s):  
Mirosław Wojnicki ◽  
Jan Lubaś ◽  
Marcin Warnecki ◽  
Jerzy Kuśnierczyk ◽  
Sławomir Szuflita
Keyword(s):  
Natural Gas ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Gas Injection ◽  
Water Injection ◽  
Experimental Studies ◽  
Carbonate Reservoir ◽  
High Nitrogen ◽  
The Impact ◽  
Wag Injection

Crucial oil reservoirs are located in naturally fractured carbonate formations and are currently reaching a mature phase of production. Hence, a cost-effective enhanced oil recovery (EOR) method is needed to achieve a satisfactory recovery factor. The paper focuses on an experimental investigation of the efficiency of water alternating sour and high-nitrogen (~85% N2) natural gas injection (WAG) in mixed-wetted carbonates that are crucial reservoir rocks for Polish oil fields. The foam-assisted water alternating gas method (FAWAG) was also tested. Both were compared with continuous water injection (CWI) and continuous gas injection (CGI). A series of coreflooding experiments were conducted within reservoir conditions (T = 126 ℃, P = 270 bar) on composite cores, and each consisted of four reservoir dolomite core plugs and was saturated with the original reservoir fluids. In turn, some of the experiments were conducted on artificially fractured cores to evaluate the impact of fractures on recovery efficiency. The performance evaluation of the tested methods was carried out by comparing oil recoveries from non-fractured composite cores, as well as fractured. In the case of non-fractured cores, the WAG injection outperformed continuous gas injection (CGI) and continuous water injection (CWI). As expected, the presence of fractures significantly reduced performance of WAG, CGI and CWI injection modes. In contrast, with regard to FAWAG, deployment of foam flow in the presence of fractures remarkably enhanced oil recovery, which confirms the possibility of using the FAWAG method in situations of premature gas breakthrough. The positive results encourage us to continue the research of the potential uses of this high-nitrogen natural gas in EOR, especially in the view of the utilization of gas reservoirs with advantageous location, high reserves and reservoir energy.

Experimental Study of Miscible Thickened Natural Gas Injection for Enhanced Oil Recovery

2017 ◽  
Vol 31 (5) ◽  
pp. 4951-4965 ◽  
Author(s):  
Nasser M. Al Hinai ◽  
A. Saeedi ◽  
Colin D. Wood ◽  
R. Valdez ◽  
Lionel Esteban
Keyword(s):  
Experimental Study ◽  
Natural Gas ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Gas Injection
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