Nuclear magnetic resonance study of CO2 flooding in tight oil reservoirs: Effects of matrix permeability and fracture

Cao, Aiqing; Li, Zhaomin; Zheng, Lei; Bai, Hao; Zhu, Di; Li, Binfei

doi:10.1016/j.geoen.2023.211692

Cited by 14 publications

(6 citation statements)

References 32 publications

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“…40 The existence of fractures reduces the pore seepage resistance and increases the contact area between CO 2 and matrix pores, which is conducive to the extraction of the crude oil from smaller pores. 41 Qian et al studied the liquid production capacity of fractured and nonfractured ends of fractured tight oil reservoirs by changing the fracture length, soaking time, and depressurization method. 42 The results show that increasing the fracture length can improve the recovery rate and the recovery rate of the pore in the core near the fracture end is effectively improved.…”

Section: Introductionmentioning

confidence: 99%

Insights into Enhancing Shale Oil Recovery Postfracturing with CO₂ Huff and Puff and Elastic Depletion Development Strategies

Li,

Huang,

Duan

et al. 2024

Energy Fuels

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After hydraulic fracturing, shale reservoirs often undergo rapid production declines during depleted development, resulting in a low cumulative production. CO 2 huff and puff emerges as a promising method to enhance shale oil recovery postfracturing. This study conducted independent experiments to investigate multistage depressurization elastic depletion development and the CO 2 huff and puff method in shale oil. The effects of injection pressure, temperature, fractures, and other parameters on the CO 2 huff and puff recovery were analyzed using nuclear magnetic resonance (NMR). The impact of the CO 2 huff and puff on crude oil in different pores was elucidated. The results show that the fluid mobility of the shale reservoir is poor, with the recovery rate of elastic depletion development being less than 10%. Conversely, a CO 2 huff and puff can enhance the recovery rate by up to 20%. The recovery rate of shale oil through a CO 2 huff and puff correlates positively with injection pressure and temperature. The initial cycle of huff and puff contributes the most to crude oil recovery, reaching up to 50%. Under equivalent parameter conditions, the presence of fractures can increase the CO 2 huff and puff efficiency by 20% compared to the matrix core. Combined with NMR experiments, the lower limit of pores that oil can be produce in matrix and fracture cores in elastic depletion development is 200 and 150 nm, respectively. In the context of CO 2 huff and puff development, these values decrease to 30 nm for matrix cores and 15 nm for fractured cores.

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Section: Introductionmentioning

confidence: 99%

Insights into Enhancing Shale Oil Recovery Postfracturing with CO₂ Huff and Puff and Elastic Depletion Development Strategies

Li,

Huang,

Duan

et al. 2024

Energy Fuels

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“…Since the 1970s, a series of studies have been carried out at home and abroad for low-porosity, low-permeability, low-pressure, and low-abundance oil reservoirs, and so far, it has been integrated into a variety of technical directions, including carbon dioxide and natural gas injection (used to increase reservoir pressure and facilitate crude oil flow) [1,2], microbial-enhanced oil recovery (employed to improve reservoir conditions and increase abundance) [3][4][5], as well as horizontal well drilling and multi-well development (utilized to expand contact area) [6,7]. Compared with the above stimulation technology, fracturing technology has the advantages of simple construction, strong effectiveness, prominent pertinence, and good controllability.…”

Section: Introductionmentioning

confidence: 99%

Research and Applications of New Fracturing Technology in Low-Abundance and Greater-Depth Well LN-1 Reservoirs

Shi,

Chen,

Wang

et al. 2024

Processes

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The upper Shasi reservoir in the LN block is characterized by low abundance and greater depth, low porosity, low permeability, and low pressure. Due to high water injection pressure, the LN block has been developed in an elastic way. The natural productivity of oil wells in this block is low, but the productivity can be improved after fracturing. However, the field development effects show that the oil well has high initial production, but rapid decline and rapid pressure drop. At present, the recovery factor of this block is only 0.38%, and it is difficult to realize the economic and effective development of a difficult-to-develop block by conventional fracturing technology. Based on the geological characteristics of the LN block and the fracturing experience of adjacent wells, the fracturing process is optimized and the key fracturing parameters are determined in combination with the sand body distribution and logging curve of well LN-1. Due to the low-pressure coefficient and medium water sensitivity of well LN-1, a new high-efficiency stimulation fracturing fluid system was selected and the formula of the fracturing fluid system was formed. The cluster perforating process is optimized according to reservoir differences, and the perforating “sweet spot” is optimized. Based on the sand body spread point of well LN-1, the high diversion channel technology and the temporary plugging and turning fracturing technology are selected to form a new fracturing and stimulation technology suitable for this kind of oil reservoir. A fracturing test was performed in layers 17# (electrical sequencing number) and 22# of well LN-1. The initial oil production was 12.5 t/d, and the stimulation effect was significantly higher than the 8.3 t/d (general fracturing) of adjacent wells. At present, the well LN-1 has been producing steadily for more than six months, and the results of this work can provide technical guidance for the efficient development of low-abundance and greater-depth oil reservoirs that are difficult to develop.

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“…Their findings were integrated with analyses of wettability and the characteristics of sweet spot reservoirs. Cao et al [23] demonstrated that the injection of carbon dioxide can enhance recovery in tight reservoir development. To this end, they conducted carbon dioxide immersion experiments using natural tight cores with varying matrix permeabilities and artificial fracture conditions.…”

Section: Introductionmentioning

confidence: 99%

Flow Characterization in Fractured Shale Oil Matrices Using Advanced Nuclear Magnetic Resonance Techniques

Li,

Sun,

Gao

et al. 2024

Processes

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The evaluation of flow dynamics in fractured shale oil reservoirs presents significant challenges due to the complex pore configurations and high organic material concentration. Conventional methods for petrophysical and fluid dynamic evaluations are insufficient in addressing these complexities. However, nuclear magnetic resonance (NMR) technology is an effective technique for quantitatively delineating fluid micro-transport properties across the reservoir core. This study presents an experimental methodology rooted in NMR technology to quantify the flow capabilities within the shale oil matrix. This approach incorporates high-pressure saturation flow experiments across seven distinct core samples to gauge the micro-transport phenomena of fluids across various pore dimensions. The results revealed that under high-pressure saturation, shale cores devoid of fractures demonstrated an average crude oil saturation rate of merely 19.44%. Cores with evident stratification exhibited a 16.18% increase in flow capacity compared to their non-stratified counterparts. The flow dynamics within these shale reservoirs exhibited a range of behaviors, from non-linear to linear. In lower-permeability zones, non-linear patterns became increasingly apparent. An NMR T2 spectrum analysis was used to identify the minimum effective pore size conducive to shale oil flow within the matrix, which was between 8 and 10 nanometers. These insights provide a foundation for a deeper understanding of the mechanisms behind oil and gas migration in fractured shale oil matrices, offering valuable insight into their extractive potential.

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Nuclear magnetic resonance study of CO2 flooding in tight oil reservoirs: Effects of matrix permeability and fracture

Cited by 14 publications

References 32 publications

Insights into Enhancing Shale Oil Recovery Postfracturing with CO₂ Huff and Puff and Elastic Depletion Development Strategies

Insights into Enhancing Shale Oil Recovery Postfracturing with CO₂ Huff and Puff and Elastic Depletion Development Strategies

Research and Applications of New Fracturing Technology in Low-Abundance and Greater-Depth Well LN-1 Reservoirs

Flow Characterization in Fractured Shale Oil Matrices Using Advanced Nuclear Magnetic Resonance Techniques

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Nuclear magnetic resonance study of CO2 flooding in tight oil reservoirs: Effects of matrix permeability and fracture

Cited by 14 publications

References 32 publications

Insights into Enhancing Shale Oil Recovery Postfracturing with CO2 Huff and Puff and Elastic Depletion Development Strategies

Insights into Enhancing Shale Oil Recovery Postfracturing with CO2 Huff and Puff and Elastic Depletion Development Strategies

Research and Applications of New Fracturing Technology in Low-Abundance and Greater-Depth Well LN-1 Reservoirs

Flow Characterization in Fractured Shale Oil Matrices Using Advanced Nuclear Magnetic Resonance Techniques

Contact Info

Product

Resources

About

Insights into Enhancing Shale Oil Recovery Postfracturing with CO₂ Huff and Puff and Elastic Depletion Development Strategies

Insights into Enhancing Shale Oil Recovery Postfracturing with CO₂ Huff and Puff and Elastic Depletion Development Strategies