Evaluating seepage radius of tight oil reservoir using digital core modeling approach

Liu, Weifeng; Chen, Shiyu; Gao, Yang; Kong, Chuixian; Jia, Ning; He, Ling; Wang, Rong; Li, Junjian

doi:10.1016/j.petrol.2019.03.072

Cited by 28 publications

(16 citation statements)

References 17 publications

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“…The G-W co-flow interval (water saturation range of gas−water twophase flow) of the three models was 33.89−69.72%, 28.83− 84.78%, and 56.55−77.12%, and the gas-phase relative permeability (Krg) at SWI was 0.357, 0.539, and 0.452 (Figure 11a). 33 Combined with the simulation results of single-phase gas flow, in fracture structure C2, due to the low resistance and high efficiency of gas driving water, the SWI was at its lowest value, and the Krg was as its highest. In fracture-pore structure C3, the fractures easily became high-permeability channels, which reduces the efficiency of gas driving water and makes it difficult for the water in the pores to be completely displaced, especially the cavities.…”

Section: Resultsmentioning

confidence: 81%

“…28−31 The 3D pore network models (PNMs) based on CT scanning can not only match the real pore structure but also extract and establish the representative elementary volume (REV) of rare samples to simulate and analyze the flow characteristics to compensate for the deficiency of experiments, theoretical modeling, and other methods. 32,33 However, there are few studies on the influence of complex pore structures on gas flow in ultradeep carbonate gas reservoirs by 3D PNM. In addition, 3D PNM can also be used to simulate gas−water two-phase (G-W) flow.…”

Section: Introductionmentioning

confidence: 99%

“…Studying gas flow in pore structures is beneficial to describing reservoir production characteristics. − 2D visualization models are widely used to observe fluid flow in porous media, but the 2D structure cannot fully reflect the complex pore structure of carbonate reservoirs, and it is not suitable for analyzing single-phase gas flow and pressure distributions. , Under certain conditions, core surface characteristics cannot effectively represent internal pore structures, which makes it difficult to fully reveal the influence of core experimental results. Developing 3D digital cores is one of the most direct and accurate methods to reflect internal pore characteristics. − The 3D pore network models (PNMs) based on CT scanning can not only match the real pore structure but also extract and establish the representative elementary volume (REV) of rare samples to simulate and analyze the flow characteristics to compensate for the deficiency of experiments, theoretical modeling, and other methods. , However, there are few studies on the influence of complex pore structures on gas flow in ultradeep carbonate gas reservoirs by 3D PNM. In addition, 3D PNM can also be used to simulate gas–water two-phase (G-W) flow.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Pore Structure on Gas Flow and Recovery in Ultradeep Carbonate Gas Reservoirs at Multiple Scales

et al. 2021

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Ultradeep carbonate gas reservoirs are a major resource of interest in clean energy development, and complex pore structures and reservoir conditions with high-temperatures and pressures are great challenges to efficient development and experimental research. It is becoming increasingly imperative to study the influence of pore structure on gas flow and productivity under reservoir conditions. Taking an ultradeep carbonate gas reservoir in the eastern Sichuan Basin, SW China, as the target reservoir, the pore structure was accurately analyzed and classified by X-ray computed tomography scanning. On this basis, three representative pore network models were established to simulate and visually analyze the gas flow characteristics at the pore scale, which effectively supplemented and perfected previous core experiments and 2D visualization research. A high-temperature and high-pressure experimental platform was built, and the influence of pore structure, heterogeneity, and irreducible water saturation (SWI) on gas flow and recovery was studied quantitatively and qualitatively for the first time through improved core experiments. The results showed that fracture characteristics, pore connectivity, and water saturation are key factors affecting gas flow and depletion strategies, and cavities constitute the main reservoir space. Under no-water conditions, the final recovery nears 72.24%, and the influence of pore structure is not obvious. Under SWI conditions, the gas flow resistance increases, and the loss of the production rate is higher than 27% based on the similarity transformation; the lower the permeability or production pressure difference is, the higher the production rate loss will be. At the same time, irreducible water leads to significant recovery losses; the final recovery is between 57.95 and 71.10%, and the recovery loss of the pore-type reservoir is much higher than that of the fracture-type reservoir. In gas reservoir development, increasing permeability is conducive to improving the production rate and recovery, especially for ″high-porosity and low-permeability″ reservoirs. If the permeability is high enough, the production pressure difference should be controlled to avoid insufficient gas supply from far-well areas and reduce interlayer interference. Therefore, it is of great significance to promote coordinated development between multiple layers in the vertical direction and between near-well area and far-well areas in the horizontal direction.

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Section: Resultsmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of Pore Structure on Gas Flow and Recovery in Ultradeep Carbonate Gas Reservoirs at Multiple Scales

et al. 2021

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“…[80] This method is harmless to the core microstructure and shows highly accurate imaging results, so it is commonly used to establish the digital core. [81,82] The numerical reconstruction methods for the establishment of a digital core consist of the stochastic simulation method (e.g., Gaussian simulation, simulated annealing, multipoint statistics) [83][84][85][86] and process simulation method. [87][88][89] The digital core can be established by the statistical information of core slice images using numerical reconstruction methods.…”

Section: Digital Core Techniquementioning

confidence: 99%

Review on Pore Structure Characterization and Microscopic Flow Mechanism of CO₂ Flooding in Porous Media

Tang

Hou

et al. 2020

Energy Tech

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Rapidly rising emissions of greenhouse gases into the atmosphere lead to the greenhouse effect and accelerate the exacerbation of the global climate. [1] Greenhouse gases include carbon dioxide (CO 2), ozone (O 3), nitric oxide (N 2 O), methane (CH 4), hydrogen fluoride, the chlorine carbide class (CFCs, HFCs, HCFCs), and perfluorinated carbide (PFCs) and sulfur hexafluoride (SF 6). The concentration of CO 2 is the highest in the atmosphere among greenhouse gases, and it significantly dominates global warming. [2] The process of the greenhouse effect and the impact of greenhouse gases on global warming are shown in Figure 1. Carbon is one of the most important elements of earth's structure and living things. It widely exists in the biosphere, lithosphere, hydrosphere, and atmosphere and circulates continuously with the movement of the Earth. CO 2 plays an important role in the cycle. Green plants absorb CO 2 from the atmosphere, and CO 2 is converted into organic matter and oxygen is also released through photosynthesis with the participation of water, as shown in Figure 2. [3,4] Before the industrial revolution, the carbon cycle has been kept in balance for millions of years. After the industrial revolution, human beings began to utilize fossil fuels to obtain energy. The balance of nature is thus destroyed, leading to climate anomalies (e.g., global warming) due to the increased concentration of CO 2 caused by the burning of fossil fuels and other industrial activities. Therefore, reducing emissions of CO 2 and other greenhouse gases is essential for protecting the natural environment. [5,6] At present, carbon emissions can be reduced by decreasing energy consumption, improving energy utilization efficiency, replacing fossil fuels with clean energy (e.g., solar energy, wind energy, geothermal energy, and hydrogen energy), and carbon capture and storage (CCS). However, it is still hard for most of the clean energy to completely replace fossil fuels in the near future because of safety, technology availability, and economical efficiency. [7] CCS is an important technological means to reduce carbon emission. [8,9] However, CCS requires high costs and may cause leakage of carbon because the captured carbon is usually sequestrated in saline aquifers, coal seams, depleted reservoirs, etc. [10-12] Therefore, carbon capture, utilization and storage (CCUS) has been acknowledged as a promising technology to achieve efficient reduction of carbon and also generate economic benefits, which is more practical and economical. [13] CO 2 is an important material for industry and has been applied in many fields, as shown in Figure 3. [14,15] In the food industry, CO 2 is used in the production of carbonized beverages, food preservation, and industrial processing as a refrigerant and protective gas. It can also be applied to synthesize chemicals, drugs, polymers, such as degradable plastics, etc. High-purity

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“…Seepage characteristics of reservoir rocks are important information in exploration and development of tight oil and gas reservoirs. Most existing investigations on seepage characteristics are based on macroscopic scale studies (Li et al 2019a, b;Lv et al 2019;Zhang et al 2019). Because the pore size of tight sandstone is relatively small (at micron level), it is necessary to carry out microscopic scale study of seepage characteristics of tight sandstone reservoirs (Babchin and Nasr 2006;Li et al 2019a, b;Ren et al 2018;Yin et al 2019;Wang et al 2020).…”

Section: Introductionmentioning

confidence: 99%

Investigating microscopic seepage characteristics and fracture effectiveness of tight sandstones: a digital core approach

Song

et al. 2020

Pet. Sci.

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Microscopic seepage characteristics are critical for the evaluation of tight sandstone reservoirs. In this study, a digital core approach integrating microscopic seepage simulation and CT scanning was developed to characterize microscopic seepage and fracture effectiveness (the ratio of micro-fractures that contributes to fluid flow) of tight sandstones. Numerical simulations were carried out for characterizations of tight sandstones. The results show that the axial permeability of the investigated cylindrical tight sandstone from Junggar Basin in China is 0.460 μm2, while the radial permeability is 0.3723 μm2, and the axial and radial effective fracture ratios are 0.4387 and 0.4806, respectively, indicating that cracks are not fully developed and the connectivity between micro-cracks is poor. Directional permeability that is difficult to measure by laboratory experiments can be obtained readily using the proposed method in this paper. The results provide important information for improving the exploration and development of tight sandstone reservoirs.

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Evaluating seepage radius of tight oil reservoir using digital core modeling approach

Cited by 28 publications

References 17 publications

Influence of Pore Structure on Gas Flow and Recovery in Ultradeep Carbonate Gas Reservoirs at Multiple Scales

Influence of Pore Structure on Gas Flow and Recovery in Ultradeep Carbonate Gas Reservoirs at Multiple Scales

Review on Pore Structure Characterization and Microscopic Flow Mechanism of CO₂ Flooding in Porous Media

Investigating microscopic seepage characteristics and fracture effectiveness of tight sandstones: a digital core approach

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Evaluating seepage radius of tight oil reservoir using digital core modeling approach

Cited by 28 publications

References 17 publications

Influence of Pore Structure on Gas Flow and Recovery in Ultradeep Carbonate Gas Reservoirs at Multiple Scales

Influence of Pore Structure on Gas Flow and Recovery in Ultradeep Carbonate Gas Reservoirs at Multiple Scales

Review on Pore Structure Characterization and Microscopic Flow Mechanism of CO2 Flooding in Porous Media

Investigating microscopic seepage characteristics and fracture effectiveness of tight sandstones: a digital core approach

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Review on Pore Structure Characterization and Microscopic Flow Mechanism of CO₂ Flooding in Porous Media