Nitrogen gas channeling characteristics in fracture-vuggy carbonate reservoirs

Qu, Ming; Hou, Jirui; Wen, Yuchen; Liang, Tuo

doi:10.1016/j.petrol.2019.106723

Cited by 36 publications

(16 citation statements)

References 16 publications

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“…These three characteristics can lead to the early breakthrough of gas, which reduces the oil displacement efficiency of CO 2 gas flooding; this problem of gas channeling can also occur during N 2 flooding (Jian et al 2019). Qu et al (2020) used visualization models and macroscopic models to simulate fractured vuggy carbonate reservoirs. On the basis of studying the gas channeling characteristics of fractured vuggy carbonate reservoirs, they proposed three risk assessment methods of gas channeling: the "PIR" of typical fractured vuggy carbonate reservoirs.…”

Section: N2 Injectionmentioning

confidence: 99%

A review of development methods and EOR technologies for carbonate reservoirs

et al. 2020

Pet. Sci.

177

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Carbonate reservoirs worldwide are complex in structure, diverse in form, and highly heterogeneous. Based on these characteristics, the reservoir stimulation technologies and fluid flow characteristics of carbonate reservoirs are briefly described in this study. The development methods and EOR technologies of carbonate reservoirs are systematically summarized, the relevant mechanisms are analyzed, and the application status of oil fields is catalogued. The challenges in the development of carbonate reservoirs are discussed, and future research directions are explored. In the current development processes of carbonate reservoirs, water flooding and gas flooding remain the primary means but are often prone to channeling problems. Chemical flooding is an effective method of tertiary oil recovery, but the harsh formation conditions require high-performance chemical agents. The application of emerging technologies can enhance the oil recovery efficiency and environmental friendliness to a certain extent, which is welcome in hard-to-recover areas such as heavy oil reservoirs, but the economic cost is often high. In future research on EOR technologies, flow field control and flow channel plugging will be the potential directions of traditional development methods, and the application of nanoparticles will revolutionize the chemical EOR methods. On the basis of diversified reservoir stimulation, combined with a variety of modern data processing schemes, multichannel EOR technologies are being developed to realize the systematic, intelligent, and cost-effective development of carbonate reservoirs.

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Section: N2 Injectionmentioning

confidence: 99%

A review of development methods and EOR technologies for carbonate reservoirs

et al. 2020

Pet. Sci.

177

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“…Conversely, the injected gas only sweeps the top part of the reservoir and bypasses oil in the bottom part. (Qu et al, 2020)…”

Section: Introductionmentioning

confidence: 98%

The development of heat‐resistant and salt‐tolerant foam with betaine surfactants

Zhang

Guo

et al. 2022

J Surfact & Detergents

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A modified instrument was designed to evaluate foam properties under high temperature and pressure. The type and molar ratio of betaine surfactants were screened to develop the heat-resistant and salt-tolerant foam for Tahe oilfield (130 C, 220 g/L), and the effects of temperature and pressure on foam properties were also investigated. The synergism between surfactants and the enhanced oil recovery (EOR) mechanism of foam flooding in fractured-vuggy reservoirs were studied. Experimental results showed the developed foam had excellent foaming ability and foam stability when the lauramidopropyl hydroxyl sulfobetaine (LHSB): erucic amide propyl betaine (EAB) molar ratio ranged from 1:1 to 1:2 (initial foam volume was 392 ml when the molar ratio was 1:1, drainage half-time was 5.75 min and foam half-time was 72 min when the molar ratio was 1:2 at 130 C and 2 MPa). The synergistic effect was found to reach its maximum when the LHSB:EAB molar ratio ranged from 1:1 to 1:2 according to interaction parameters, which agreed with the results of foam properties. Foam stability was found to considerably increase with increasing pressure, but decrease with increasing temperature. However, temperature and pressure were found to have consistent effects on foaming ability, that is, the foaming ability increased with increasing temperature and pressure. The flooding test showed foam flooding exhibited better sweep efficiency and higher recovery ratio in the fractured-vuggy model than gas flooding and water flooding. This could be because injected foam did not channel through the top (or bottom) path due to its high viscosity and moderate density.

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“…Air flooding has succeeded in oil reservoirs with relatively homogeneous formation properties, with significant economic benefits. For continental sedimentary reservoirs with severe heterogeneity, the risk of gas channeling is greater [ 5 , 6 ]. In addition, to prevent explosions and ensure the safety and controllability of air flooding, light oil reservoirs are usually flooded with oxygen-reduced air.…”

Section: Introductionmentioning

confidence: 99%

Identification of Gas Channeling and Construction of a Gel-Enhanced Foam Plugging System for Oxygen-Reduced Air Flooding in the Changqing Oilfield

Wang

Qin

et al. 2022

Gels

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The accurate identification of gas channeling channels during foam-assisted oxygen-reduced air flooding (FAORAF) and the analysis of the main controlling factors are essential to propose reasonable and effective countermeasures to enhance oil recovery (EOR). However, there are few comprehensive studies on identifying gas channeling channels, the influencing factors, and the corresponding plugging EOR systems in FAORAF. The channeling channels of the injection and production wells of the Changqing Oilfield, China, under varying development schemes are identified utilizing fuzzy membership function theory in this work to obtain their primary distribution. The characteristics and influence factors of gas channeling channels are analyzed by numerical simulation using CMG. The recovery performance of each foam blocking system is evaluated by twin-tube sand pack models. As well, based on the features of reservoir fractures, a new gel-enhanced foam plugging system is developed. The results show that channeling channels chiefly develop along NE 60–70° and that foam could reduce gas channeling. Natural and artificial fractures are the principal factors causing gas channeling, followed by the injection method and gas injection rate. Under the premise of the injection and migration efficiency, the optimal gel system is a 0.1% HPAM + 0.1% organic chromium crosslinking agent. The addition of gel increases the viscosity of the liquid phase and strengthens the mechanical strength of the foam liquid film. At a permeability ratio of 12, the recovery factors of the binary plugging systems composed of microspheres, PEG, and gel combined with foam are 40.89%, 45.85%, and 53.33%, respectively. The movable gel foam system has a short breaking time (only 18 days) and a recovery factor of about 40% at a permeability ratio of 20. To be suitable for oil reservoirs with microfractures, an improved ternary gel foam system—0.1% HPAM + 0.1% chromium crosslinking agent + 0.05–0.1% nano-SiO2—is developed. Compared with the binary gel foam system, the recovery rate of the new nano-SiO2 gel foam system after 15 days of ageing using the core splitting test is 25.24% during the FAORAF process, increasing by 12.38%.

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Nitrogen gas channeling characteristics in fracture-vuggy carbonate reservoirs

Cited by 36 publications

References 16 publications

A review of development methods and EOR technologies for carbonate reservoirs

A review of development methods and EOR technologies for carbonate reservoirs

The development of heat‐resistant and salt‐tolerant foam with betaine surfactants

Identification of Gas Channeling and Construction of a Gel-Enhanced Foam Plugging System for Oxygen-Reduced Air Flooding in the Changqing Oilfield

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