scholarly journals Numerical Simulation via CFD Methods of Nitrogen Flooding in Carbonate Fractured-Vuggy Reservoirs

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7554
Author(s):  
Kexing Li ◽  
Bowen Chen ◽  
Wanfen Pu ◽  
Jianhai Wang ◽  
Yongliang Liu ◽  
...  
Keyword(s):  
Conceptual Model ◽  
Oil Recovery ◽  
High Speed ◽  
Physical Simulation ◽  
Fluid Dynamic ◽  
Gas Injection ◽  
Water Flooding ◽  
Injection Mode ◽  
Well Pattern ◽  
Gas Channeling

A reservoir-scale numerical conceptual model was established according to the actual geological characteristics of a carbonate fractured-vuggy reservoir. Considering the difference in density and viscosity of fluids under reservoir conditions, CFD (computational fluid dynamic) porous medium model was applied to simulate the process of nitrogen displacement in a fractured-vuggy reservoir after water flooding. The effects of gas injection rate, injection mode, and injector–producer location relation were studied. The results show that nitrogen flooding can yield additional oil recovery of 7–15% after water flooding. Low-speed nitrogen injection is beneficial in obtaining higher oil recovery. High speed injection can expand the sweep area, but gas channeling occurs more easily. In gas–water mixed injection mode, there is fluid disturbance in the reservoir. The gas channeling is faster in low injector–high producer mode, while the high injector–low producer mode is beneficial for increasing the gas sweep range. Nevertheless, the increment of recovery is closely related to well pattern. After nitrogen flooding, there are still a lot of remaining oil distributed in the trap area of gas cap and bottom water in the reservoir that water and gas injection can’t sweep. The establishment of the numerical conceptual model compensates for the deficiency of physical simulation research, stating that only limited parameters can be simulated during experiments, and provides theoretical bases for nitrogen flooding in fractured-vuggy reservoir.

The Research of Flood Pattern Completeness in the Thin and Poor Oil Layers of South West II Area

2012 ◽  
Vol 594-597 ◽  
pp. 2541-2544
Author(s):  
Xiao Hui Wu ◽  
Kao Ping Song ◽  
Chi Dong ◽  
Ji Cheng Zhang ◽  
Jing Fu Deng
Keyword(s):  
Oil Recovery ◽  
Water Flooding ◽  
South West ◽  
Oil Distribution ◽  
Well Pattern ◽  
Remaining Oil ◽  
Tertiary Oil Recovery ◽  
Well Pattern Optimization ◽  
Numerical Simulation Technique

As line well pattern is the main development technique in the thin and poor oil layers of Daqing Oilfield South West Ⅱ PⅠ group, the layers have been idle and the degree of reserve recovery is far less than the region level. In response to these problems, we analyzed the balanced flood performance of various layers and the remaining oil distribution through numerical simulation technique. It shows that, the main remaining oil type of intended layers is caused by voidage-injection imperfection. Considering the needs of the follow-up infill well pattern and tertiary oil recovery, we decided to keep the well network independent and integrated without disturbing the pattern configuration and main mining object of various sets of well pattern. Finally we confirmed to perforate-adding the first infill wells of intended layers to consummate the water flooding regime. Through analyzing the production target of different well pattern optimization programs relatively, it shows that the best program has regular well pattern and large drilled thickness.

scholarly journals Asynchronous Injection-Production Process: A Method to Improve Water Flooding Recovery in Complex Fault Block Reservoirs

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Shibao Yuan ◽  
Rui Wang ◽  
Haiyan Jiang ◽  
Qing Xie ◽  
Shengnan Chen ◽  
...  
Keyword(s):  
Production Process ◽  
Oil Recovery ◽  
Water Injection ◽  
Central Area ◽  
Water Flooding ◽  
Production Stage ◽  
Fault Block ◽  
Complex Fault ◽  
Well Pattern ◽  
Remaining Oil

The complex fault block reservoir has the characteristics of small area and many layers in vertical. Due to the influence of formation heterogeneity and well pattern, the situation that “water fingering is serious with water injection, on the contrary, driving energy is low” frequently occurs in water flooding, which makes it difficult to enhance oil recovery. Asynchronous injection-production (AIP) process divides the conventional continuous injection-production process into two independent processes: injection stage and production stage. In order to study oil recovery in the fault block reservoir by AIP technology, a triangle closed block reservoir is divided into 7 subareas. The result of numerical simulation indicates that all subareas have the characteristic of fluid diverting and remaining oil in the central area is also affected by injected water at injection stage of AIP technology. Remaining oil in the central area is driven to the included angle and border area by injected water and then produced at the production stage. Finally, the oil recovery in the central area rises by 5.2% and in the noncentral area is also increased in different levels. The AIP process can realize the alternative change of reservoir pressure, change the distribution of flow field, and enlarge the swept area by injected water. To sum it up, the AIP process is an effective method to improve the oil recovery in complex fault-block reservoir by water flooding.

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.

Study on Minimum Miscible Pressure and Oil Displacement Law for CO2 Flooding

2011 ◽  
Vol 391-392 ◽  
pp. 1051-1054
Author(s):  
Shu Li Chen ◽  
Wen Xiang Wu ◽  
Jia Bin Tang
Keyword(s):  
Oil Recovery ◽  
Gas Injection ◽  
Injection Pressure ◽  
Water Flooding ◽  
Tube Model ◽  
Gas Oil ◽  
Core Flooding ◽  
Oil Displacement ◽  
Gas Flooding ◽  
Cumulative Recovery

In laboratory, the minimum miscible pressure (MMP) of oil and CO2 was studied by using a slim tube model. The results showed that the greater the gas injection pressure, the higher the cumulative recovery. The gas breakthrough when the gas was injected with a volume of 0.7~0.8PV, the trend of cumulative recovery increase slowed down and the produced gas-oil ratio increased dramatically. Core flooding experiments were carried to compare the effects of CO2 and water flooding. As a result, the ultimate oil recovery of CO2 flooding increased with the increase of gas injection pressure. If the gas flooding was miscible, the ultimate recovery of CO2 flooding was generally higher than that of water flooding.

scholarly journals Experimental Study on Enhanced Oil Recovery by Nitrogen-Water Alternative Injection in Reservoir with Natural Fractures

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Xiang Li ◽  
Yuan Cheng ◽  
Wulong Tao ◽  
Shalake Sarulicaoketi ◽  
Xuhui Ji ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Gas Injection ◽  
Water Injection ◽  
Injection Pressure ◽  
Injection Rate ◽  
Water Flooding ◽  
Orthogonal Experimental Design ◽  
Fractured Reservoir ◽  
Natural Fractures ◽  
Nitrogen Injection

The production of a low permeability reservoir decreases rapidly by depletion development, and it needs to supplement formation energy to obtain stable production. Common energy supplement methods include water injection and gas injection. Nitrogen injection is an economic and effective development method for specific reservoir types. In order to study the feasibility and reasonable injection parameters of nitrogen injection development of fractured reservoir, this paper uses long cores to carry out displacement experiment. Firstly, the effects of water injection and nitrogen injection development of a fractured reservoir are compared through experiments to demonstrate the feasibility of nitrogen injection development of the fractured reservoir. Secondly, the effects of gas-water alternate displacement after water drive and gas-water alternate displacement after gas drive are compared through experiments to study the situation of water injection or gas injection development. Finally, the reasonable parameters of nitrogen gas-water alternate injection are optimized by orthogonal experimental design. Results show that nitrogen injection can effectively enhance oil production of the reservoir with natural fractures in early periods, but gas channeling easily occurs in continuous nitrogen flooding. After water flooding, gas-water alternate flooding can effectively reduce the injection pressure and improve the reservoir recovery, but the time of gas-water alternate injection cannot be too late. It is revealed that the factors influencing the nitrogen-water alternative effect are sorted from large to small as follows: cycle injected volume, nitrogen and water slug ratio, and injection rate. The optimal cycle injected volume is around 1 PV, the nitrogen and water slug ratio is between 1 and 2, and the injection rate is between 0.1 and 0.2 mL/min.

Scheme to Tap Remaining Oil Potential in Poor Pay Zones

2013 ◽  
Vol 734-737 ◽  
pp. 1257-1261
Author(s):  
Ji Cheng Zhang ◽  
Shu Hong Zhao ◽  
Jin Yu Lan ◽  
Kao Ping Song
Keyword(s):  
Oil Recovery ◽  
Water Flooding ◽  
Oil Distribution ◽  
Well Pattern ◽  
Remaining Oil ◽  
Tertiary Oil Recovery ◽  
Well Pattern Optimization ◽  
Numerical Simulation Technique ◽  
Production Target

This paper analyzed the balanced flood performance of various layers and the remaining oil distribution through numerical simulation technique. It shows that, the main remaining oil type of intended layers is caused by voidage-injection imperfection. Considering the needs of the follow-up infill well pattern and tertiary oil recovery, we decide to maintain the relative independence and integrity of each well network without disturbing the pattern configuration and the mining exploit object of various sets of well pattern. Finally we confirm to perforate adding the first infill wells of intended layers to consummate the water flooding regime. Through analyzing the production target of different well pattern optimization programs relatively, it shows that the best program has regular well pattern and large drilled thickness.

Experimental Research on Hot Water Flooding of Different Rhythm Heavy Oil Reservoir after the Steam Injection

2012 ◽  
Vol 550-553 ◽  
pp. 2878-2882 ◽  
Author(s):  
Ping Yuan Gai ◽  
Fang Hao Yin ◽  
Ting Ting Hao ◽  
Zhong Ping Zhang
Keyword(s):  
Oil Recovery ◽  
Heavy Oil ◽  
Physical Simulation ◽  
Steam Injection ◽  
Hot Water ◽  
Water Flooding ◽  
Oil Reservoir ◽  
Steam Flooding ◽  
Heavy Oil Reservoir ◽  
Swept Volume

Based on the issue of enhancing oil recovery of heavy oil reservoir after steam injection, this paper studied the development characteristics of hot water flooding in different rhythm (positive rhythm, anti-rhythm, complex rhythm) reservoir after steam drive by means of physical simulation. The research shows that the positive rhythm reservoir has a large swept volume with steam flooding under the influence of steam overlay and steam channeling. Anti-rhythm reservoir has a large swept volume with hot water flooding, because hot water firstly flows along the high permeability region in upper part of the reservoir, in the process of displacement, hot water migrates to the bottom of reservoir successively for its higher density.

scholarly journals Development of Proxy Models for Screening Water Flood and Gas Flood Candidates

2021 ◽  
pp. 51-57
Author(s):  
Moyosore, Olanipekun ◽  
Akpabio, Julius U. ◽  
Isehunwa, Sunday O.
Keyword(s):  
Oil Recovery ◽  
Gas Injection ◽  
Water Injection ◽  
Screening Method ◽  
Water Flooding ◽  
Improved Oil Recovery ◽  
Screening Criteria ◽  
Recovery Techniques ◽  
Oil Formation Volume Factor ◽  
Proxy Models

Fluid-flood and other improved oil recovery techniques are becoming prominent in global petroleum production because a large proportion of production is from mature oil fields. Although water flooding and gas injection are well established techniques in the industry, several of the screening criteria in literature are discipline which could sometimes be subjective. This work used experimental design techniques to develop proxy models for predicting oil recovery under water-flood and gas-flood conditions. The objective of the study is to develop a quantitative screening method that would allow for candidates to be evaluated and ranked for water flood or gas injection. The model was applied to some field cases and compared with published models and the well-known Welge Analysis method. The coefficient constants for the oil formation volume factor for water flooding and gas injection was 0.0139 and 0.0434 respectively. Similarly, the coefficient constants for water injection and gas injection for the generated proxy model was -2.34* 10-8 and -6.1 *10-5 respectively. The results show that the proxy models developed are quite robust and can be used for first pass screening of water and gas flood candidates. 

scholarly journals An experimental study of alternative hot water alternating gas injection in a fractured model

2018 ◽  
Vol 37 (3) ◽  
pp. 945-959 ◽  
Author(s):  
Amirhossein Ebadati ◽  
Erfan Akbari ◽  
Afshin Davarpanah
Keyword(s):  
Oil Recovery ◽  
Gas Injection ◽  
Conventional Technique ◽  
Hot Water ◽  
Recovery Factor ◽  
Water Flooding ◽  
Fractured Reservoir ◽  
Carbon Dioxide Gas ◽  
Water Alternating Gas ◽  
Alternative Water

Alternative injection of gas as slugs with water slugs, or alternative water gas injection, is the conventional technique for improving the recovery factor due to its high potential for mobilizing the residual oil in place in the reservoirs and to control gas mobility. The water alternating gas methodology is a combination of two oil recovery procedures: gas injection and waterflooding. The principal parameters that must be evaluated in water alternating gas injection in laboratory scale are reservoir heterogeneity, rock type, and fluid properties. In the current investigation, a feasibility study has been performed to analyze the five various scenarios of enhanced oil recovery techniques and compare them experimentally. The laboratory experiments are done for one of the Iranian reservoirs which have been subjected to waterflooding for several years, and the amount of recovery factor for water flooding is about 42%. The results of this study illustrate that water alternating gas injection and hot water alternating gas injection exert a profound impact on the amount of recovery factor. Moreover, the primary purpose of this study is to assess the application of alternative hot water and hot carbon dioxide gas injections in the conventional and fractured reservoir model.

scholarly journals Investigation effect of wettability and heterogeneity in water flooding and on microscopic residual oil distribution in tight sandstone cores with NMR technique

Open Physics ◽  
2017 ◽  
Vol 15 (1) ◽  
pp. 544-550 ◽  
Author(s):  
Pufu Xiao ◽  
Xiaoyong Leng ◽  
Hanmin Xiao ◽  
Linghui Sun ◽  
Haiqin Zhang ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Physical Simulation ◽  
Spontaneous Imbibition ◽  
Recovery Factor ◽  
Water Flooding ◽  
Pore Throat ◽  
Tight Sandstone ◽  
Large Pore ◽  
Oil Distribution ◽  
The Difference

AbstractIn order to explore the effect of wettability and pore throat heterogeneity on oil recovery efficiency in porous media, physical simulation experiment and nuclear magnetic resonance (NMR) measurements were conducted to investigate how crude oil residing in different sized pores are recovered by water flooding. Experimental results indicate that the recovery factor of water flooding is governed by spontaneous imbibition and also pore throat heterogeneity. It is found that intermediate wetting cores lead to the highest final recovery factor in comparison with water wet cores and weak oil wet cores, and the recovery oil difference in clay micro pore is mainly because of the wettability, the difference in medium pore and large pore is affected by pore throat heterogeneity. Water wet core has a lower recovery factor in medium and large pore due to its poor heterogeneity, in spite of the spontaneous imbibition effect is very satisfying. Intermediate wetting cores has significant result in different sized pore and throat, the difference in medium pore and large pore is affected by pore throat heterogeneity.

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