Experimental investigation of immiscible water-alternating-gas injection in ultra-high water-cut stage reservoir

Kong, Debin; Gao, Yanxiao; Sarma, Hemanta Kumar; Li, Yiqiang; Guo, Hu; Zhu, Weiyao

doi:10.46690/ager.2021.02.04

Cited by 34 publications

(12 citation statements)

References 34 publications

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“…(7) The changes in oil-repelling efficiency and crude oil utilization in different pore throats are calculated according to the changes in the T2 spectrum. (8) The T2 spectra that are measured by the NMR experiments are transformed into pore radius distribution, according to the transformation relationship between relaxation time distribution and pore radius distribution [14,15].…”

Section: Experimental Stepsmentioning

confidence: 99%

“…The focus of the above researchers was on how to develop flow control systems with better results, but how to combine flow control systems with more mature processes to improve crude oil recovery seems to be the question of interest for oil producers. Currently, the main flow control systems that are used to seal gas scramble are water/gas alternate injection (WAG), CO 2 foam injection, and CO 2 foam gel injection [15][16][17]. In mine practice, improper combinations of different flow control systems and mismatches with formation pore throats have caused oil in large pore channels to be squeezed into small pore throats without being driven out [18], and plugging failure affecting the final recovery is reported from time to time.…”

Section: Introductionmentioning

confidence: 99%

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Study on the Plugging Limit and Combination of CO2 Displacement Flow Control System Based on Nuclear Magnetic Resonance (NMR)

Yang

Cao³

et al. 2022

Processes

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CO2 displacement is an important technology to reduce emissions and improve crude oil recovery, as well as prevent CO2 escape. Effective storage is key to the successful implementation of this technology, especially for medium and high permeability reservoirs. The current flow control systems that are applied to seal gas escape are mainly gas/water alternation, CO2 foam, and CO2 foam gel, but there is no clear understanding of the plugging limits of various flow control systems and the mechanism of their combined use of residual oil. Therefore, in this paper, a series of core replacement experiments are conducted for different flow control systems and their combinations. The quantitative characterization of the core pore size distribution before and after the replacement is carried out using the NMR technique to try and determine the plugging limits of different plugging systems, and to investigate the residual oil utilization patterns of self-designed flow control system combinations and common flow control system combinations under two reservoir conditions with and without large pores. The results show that the plugging limits of water/gas alternation, CO2 foam, and CO2 foam gel systems are 0.86–21.35 μm, 0.07–28.23 μm, and 7–100 μm, respectively, as inferred from the T2 (lateral relaxation time) distribution and pore size distribution. When different combinations of flow control systems are used for repelling, for reservoirs without large pore channels, the combination of flow control systems using higher strength CO2 foam first can effectively improve the degree of crude oil mobilization in small pore throats, compared to using gas/water alternation directly. For reservoirs containing large pore channels, using high-strength CO2 foam gel first to seal the large pore channels increases the degree of utilization of the large pore channels; using water/gas alternation first causes damage to the middle pore channels; High-strength CO2 foam gel seals the large pore channels when the plugging strength is not enough; and using water/gas alternation can effectively improve the degree of utilization of small and medium pore channels. The results of this paper can provide theoretical guidance for the multi-stage flow control of CO2 displacement in the field.

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Section: Experimental Stepsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study on the Plugging Limit and Combination of CO2 Displacement Flow Control System Based on Nuclear Magnetic Resonance (NMR)

Yang

Cao³

et al. 2022

Processes

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“…Channeling of the injected fluid due to reservoir heterogeneity will reduce the swept fluid volume and reduce oil recovery. , No matter whether conventional or unconventional reservoirs − or gas − or water injection, plugging the dominant channels and expanding the swept volume of the injected fluid are the developmental ideas throughout the whole process of oil and gas field development . Additionally, due to the influence of reservoir wettability, the injected fluid tends to invade the pore throats with the least flow resistance under the action of a capillary force, which will also lead to the formation of dominant channels. , Therefore, the optimal selection of profile control agents and the revelation of their transport and plugging mechanisms in porous media are the focus of research. − …”

Section: Introductionmentioning

confidence: 99%

Pore-Scale Transport Dynamic Behavior of Microspheres and Their Mechanisms for Enhanced Oil Recovery

Chen,

Li,

et al. 2024

Energy Fuels

Self Cite

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Polymer microsphere transport in porous media widely appears in oil field development. However, the migration and plugging mechanisms of the microspheres at the pore-throat scale need further study. In this paper, four pore-throat and one reservoir etching models were designed to simulate the pore throat distribution with different heterogeneities and real reservoir pore structures, respectively. The pore-throat matching relationship, dynamic transport behavior, and enhanced oil recovery (EOR) mechanisms of microspheres were clarified based on the injectivity and displacement experiments. The results show that microspheres will preferentially occupy larger pores and throats, showing obvious selective plugging characteristics. Taking the absence of microspheres entering and retention in the throat as the basis for the mismatch between microspheres and pore throats, the upper limits of the matching factors of the sectional model and the axial model are 1.21 and 1.47, respectively, which is consistent with the macroscopic matching results. Microspheres have a significant liquid flow diversion effect, which can force the solution flow into the unswept small throat area and simultaneously displace blindend residual oil and film residual oil in the swept throats. Microspheres can further increase the oil recovery by 6.85% compared with polymer flooding through three mechanisms: increasing the injection pressure, plugging dominant channels, and further dispersing the continuous remaining oil. The impact of the heterogeneity of the microsphere particle size and reservoir pore throat structure on microsphere migration and EOR effects will be a future research topic.

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“…The occurrence state of tight oil will be comprehensively affected by temperature, pressure, pore size, pore mineral composition, fluid composition and other factors (Liu et al, 2020). For unconventional reservoirs such as tight oil, the occurrence state of fluid in reservoirs is quite different from that of conventional oil and gas reservoirs (Kong et al, 2021). At present, the occurrence state of pore fluid in tight oil reservoirs of Lucaogou Formation in Jimusar Sag, Xinjiang is unclear, the description of the availability of pore fluid is not accurate, and the development effect is not ideal.…”

Section: Introductionmentioning

confidence: 99%

Study on gas injection development effect of tight reservoir based on fluid occurrence state

Lin¹,

An²,

Hou³

et al. 2023

Front. Energy Res.

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Based on the tight oil reservoir conditions of Lucaogou Formation in Jimusar Sag, Xinjiang, this paper conducts a full-scale characterization experiment of pore structure and designs the optimization numerical simulation of the development scheme based on the geological model combination with the fluid occurrence state. A comparative study on the development methods of tight reservoirs shows that the enhanced oil recovery effect of CO2 flooding is obviously better than that of CH4 flooding and water flooding. When the production bottom hole pressure is lower than the formation fluid saturation pressure, changing the production bottom hole pressure has little impact on the productivity of CO2 flooding in tight reservoirs. The recovery factor increases with the increase of injection rate, but when the injection rate is higher than 15,000 m³/d, the increase of oil recovery and the oil change rate decrease obviously; The complex fractures near the well can help to increase the swept volume of CO2 flooding, while the complex fractures far away from the well will cause channeling, which is not conducive to production. Combined with the occurrence state of the fluid, it is obtained that in the process of CO2 displacement, when the adsorption is considered, when the adsorption components are the same, with the increase of the adsorption capacity, the recovery factor decreases; When the adsorption capacity is constant, the higher the proportion of heavy components is, the lower the recovery factor is; With the increase of adsorption capacity, the permeability decreases more. The fluid occurrence state in tight oil reservoirs is very different from that in conventional reservoirs, and the adsorption phase accounts for a larger proportion, which seriously affects the flow capacity of the fluid during the development process. However, conventional numerical simulation rarely considers the influence of fluid occurrence state.

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Experimental investigation of immiscible water-alternating-gas injection in ultra-high water-cut stage reservoir

Abstract: Experimental investigation of immiscible water-alternating-gas injection in ultra-high water-cut stage reservoir.

Cited by 34 publications

References 34 publications

Study on the Plugging Limit and Combination of CO2 Displacement Flow Control System Based on Nuclear Magnetic Resonance (NMR)

Study on the Plugging Limit and Combination of CO2 Displacement Flow Control System Based on Nuclear Magnetic Resonance (NMR)

Pore-Scale Transport Dynamic Behavior of Microspheres and Their Mechanisms for Enhanced Oil Recovery

Study on gas injection development effect of tight reservoir based on fluid occurrence state

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