Comprehensive evaluation of waterflooding front in low‐permeability reservoir

Wang, Chunsheng; Sun, Zhang‐Hua; Sun, Qiji; Zhang, Lei; Zhang, Xueqiang

doi:10.1002/ese3.948

Cited by 14 publications

(3 citation statements)

References 7 publications

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“…However, due to complex diagenesis and geological structures, the heterogeneity of ultralow-permeability reservoirs is strong, which greatly increases the difficulty of reservoir development [1][2][3][4][5]. Ultra-low-permeability reservoirs with low porosity, low permeability, and strong heterogeneity are developed to address conventional water flooding, which often faces difficulty in water injection and has a low production capacity [6][7][8][9][10]. The existing research results show that compared to traditional water flooding, CO 2 has a better ability to enhance oil recovery in ultra-low-permeability reservoirs because of its unique properties.…”

Section: Introductionmentioning

confidence: 99%

A Study on the Plugging Effect of Different Plugging Agent Combinations during CO2 Flooding in Heterogeneous Reservoirs

Zhang,

Ji,

et al. 2024

Energies

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Gas channeling control is key to improving CO2-flooding efficiency. A traditional plugging system has disadvantages, such as poor adaptability and stability, leading to the poor plugging effect of CO2 channeling in heterogeneous reservoirs and difficulty in controlling the subsequent CO2 injection pressure. To achieve a significant plugging effect and effectively control the subsequent CO2 injection pressure, a heterogeneous physical model of gas channeling in a horizontal well was established, and plugging experiments were conducted using four different combinations of plugging agents during CO2 flooding. Three evaluation parameters were defined, including the temperature field variation coefficient (TFVC), medium-permeability diversion rate (MPDR), and subsequent injection pressure coefficient (SIPC). The plugging effect of different combinations of plugging agents during CO2 flooding in heterogeneous reservoirs was analyzed. The results show that the plugging effect after using a combination of plugging agents was significantly better than after using a single plugging agent, and different plugging agent combinations had distinct characteristics. The strong–medium–weak (S-M-W) combination had the best MPDR for subsequent CO2 flooding, but the SIPC was the highest. The strong–weak–strong–weak (S-W-S-W) and weak–strong–weak–strong (W-S-W-S) combinations could effectively control the SIPC. These results indicate that plugging using the S-W-S-W and W-S-W-S combinations can achieve an effective plugging effect and reasonably control the subsequent CO2 injection pressure. This work provides a personalized design scheme for effective gas channeling control and maintenance of appropriate injection pressure during CO2 flooding in heterogeneous reservoirs.

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Section: Introductionmentioning

confidence: 99%

A Study on the Plugging Effect of Different Plugging Agent Combinations during CO2 Flooding in Heterogeneous Reservoirs

Zhang,

Ji,

et al. 2024

Energies

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“…However, the combination of "horizontal well + reservoir modification" in hydraulic fracturing frequently results in water channeling. This method is characterized by initially high output rates, followed by slow or ineffective water injection and a swift decline in production, leading to a primary recovery rate of merely about 5-10% [25][26][27]. The core issue is derived from the fracturing modification methods not sufficiently changing the permeability of the majority of reservoir matrices.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Combination Mechanism of Spontaneous Imbibition and Water Flooding in Tight Oil Reservoirs Based on Nuclear Magnetic Resonance

Tao,

Wang,

Bai

et al. 2024

Energies

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As conventional oil reservoirs are gradually being depleted, researchers worldwide are progressively shifting their focus towards the development and comprehensive study of tight oil reservoirs. Considering that hydraulic fracturing is one of the main approaches for developing tight sandstone reservoirs, it is of great significance to explore the mechanism of spontaneous imbibition and waterflooding behavior after hydraulic fracturing in tight oil reservoirs. This research delves into the analysis of tight sandstone core samples obtained from the Shahejie Formation in the Bohai Bay Basin. All core samples are used for a series of experiments, including spontaneous imbibition and water flooding experiments. An additional well-shut period experiment is designed to understand the impact and operational dynamics of well shut-in procedures in tight reservoir development. Utilizing nuclear magnetic resonance (NMR) technology, the pore sizes of a sample are divided into three types, namely, macropores (>100 ms), mesopores (10–100 ms), and micropores (<10 ms), to thoroughly assess the fluid distribution and changes in fluid signals during the spontaneous imbibition and water flooding stages. Experimental outcomes reveal that during the spontaneous imbibition stage, oil recovery ranges from 12.23% to 18.70%, predominantly depending on capillary forces. The final oil recovery initially rises and then falls as permeability decreases, while the contribution of micropores progressively grows as the share of mesopores and macropores deceases. With water flooding processes carried out after spontaneous imbibition, enhanced oil recovery is observed between 28.26% and 33.50% and is directly proportional to permeability. The well shut-in procedures can elevate the oil recovery to as high as 47.66% by optimizing energy balance.

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“…We observed a direct correlation between the micro-heterogeneity of the reservoir and the difference in water saturation levels, i.e., the less the difference between the waterflood front and irreducible water, the more heterogeneous the reservoir. This micro-heterogeneity can increase the likelihood of 'fingering', which can consequently result in early water breakthroughs in oil wells [65,66]. In the case of the relationship curve between the water cut ( f w ) and water saturation (S w ), we used Point (S wc , 0) to draw a tangent to the water cut curve.…”

mentioning

confidence: 99%

The Influence of Micro-Heterogeneity on Water Injection Development in Low-Permeability Sandstone Oil Reservoirs

Li,

Qu,

Wang

et al. 2023

Minerals

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Micro-heterogeneity in low-permeability sandstone oil reservoirs significantly influences the uniformity of water injection during development. This leads to the formation of preferred channels for water injection, causing premature water breakthroughs in oil wells. Not only does this reduce oil displacement efficiency, but it also enriches residual oil in the formation, which ultimately impacts the overall recovery rate. This study employed various methods, including thin-section casting, qualitative analysis through scanning electron microscopy, quantitative analysis of X-ray diffraction, high-pressure mercury intrusion and particle size, and experimental techniques, such as wettability and micro-displacement, to investigate the impact mechanism of micro-heterogeneity on water injection development in low-permeability oil reservoirs. A typical low-permeability sandstone oil reservoir in the Ordos Basin was used as a case study. The results reveal that the reservoir’s micro-heterogeneity is determined by the heterogeneity of the interstitial material, porosity, and particle size. Micro-heterogeneity plays a critical role in the flow characteristics and oil displacement efficiency of low-permeability oil reservoirs. The less the micro-heterogeneity, the better the water injection development outcome. This study suggests a technical policy adjustment method that is critical for guiding the development of low-permeability water injection oil reservoirs, thereby improving the effectiveness of water injection development.

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Comprehensive evaluation of waterflooding front in low‐permeability reservoir

Cited by 14 publications

References 7 publications

A Study on the Plugging Effect of Different Plugging Agent Combinations during CO2 Flooding in Heterogeneous Reservoirs

A Study on the Plugging Effect of Different Plugging Agent Combinations during CO2 Flooding in Heterogeneous Reservoirs

Investigation of the Combination Mechanism of Spontaneous Imbibition and Water Flooding in Tight Oil Reservoirs Based on Nuclear Magnetic Resonance

The Influence of Micro-Heterogeneity on Water Injection Development in Low-Permeability Sandstone Oil Reservoirs

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