Novel method for determining the lower producing limits of pore-throat radius and permeability in tight oil reservoirs

Xiao, Qi; Wang, Zhiyuan; Yang, Zhengming; Xiang, Zuping; Liu, Zhonghua; Yang, Wei

doi:10.1016/j.egyr.2021.03.011

Cited by 14 publications

(10 citation statements)

References 16 publications

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“…The macroscopic seepage capacity of the reservoir is strongly influenced by the microscopic pore structure and the throat of tight sandstone reservoirs. The pore size determines the ability of the rock to store oil and gas, and the radius and shape of the throat determine the seepage capacity of oil and gas [43][44][45]. For a given pressure difference, the smaller the throat radius, the higher the capillary pressure, and the greater the resistance to the flow of oil and gas, and the flow rate of oil and gas will be smaller.…”

Section: Minimum Flow-pore-throat Radius-based Methodsmentioning

confidence: 99%

Research Status, Existing Problems, and the Prospect of New Methods of Determining the Lower Limit of the Physical Properties of Tight Sandstone Reservoirs

Wang

Liu

et al. 2023

Energies

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At present, many methods are used to determine the lower limits of physical properties (PPLLs) of tight sandstone reservoirs, such as empirical statistics, oil occurrence, and logging parameter crossplots, but the accuracy with which these methods obtain the lower limit of physical properties depends entirely on the number of test production data, and they are not suitable for tight sandstone reservoirs with a low degree of exploration and a lack of prediction. Compared to these mature methods, it can be concluded that the water-film-thickness-based method, which integrates factors such as formation temperature, formation pressure, mineral wettability, and formation water salinity, can characterize PPLLs using the minimum pore throat radius for hydrocarbon migration, which has a better theoretical basis and technical advantages. However, the water-film thickness is not a fixed value and cannot be directly measured in the laboratory. The molecular simulation method, known as a computational microscope, has become an effective means of investigating nano effects. By accurately investigating the interactions between rock minerals and the formation of water on atomic and molecular scales based on increasingly improved studies of the molecular force field, this method can overcome the deficiencies of the laboratory study of water films and precisely characterize the water films’ thickness. The intersection of molecular simulation and geology can bring about new methods and new research ideas for determining the lower limit of the physical properties of tight sandstone reservoirs and has broad application prospects.

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Section: Minimum Flow-pore-throat Radius-based Methodsmentioning

confidence: 99%

Research Status, Existing Problems, and the Prospect of New Methods of Determining the Lower Limit of the Physical Properties of Tight Sandstone Reservoirs

Wang

Liu

et al. 2023

Energies

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“…The lower limit of the average immovable fluid pore radius in the imbibition process (10 nm) is smaller than that in the displacement process (40 nm). Xiao et al 47 determined the lower limit of the pore throat radius by calculating the thickness of the combined water film of the reservoir. The result is that the lower limit of the producing radius of the Daqing tight reservoir is about 22 nm, while the lower limit of the producing radius of the Changqing tight reservoir is 18 nm, which is consistent with our results.…”

Section: Oil Absorption and Water Drainage And Watermentioning

confidence: 99%

Evaluation of the Lower Producing Limit of the Pore Radius for Imbibition and Displacement Based on Shale Oil Reservoir Characteristics

Lai

Deng

Wang³

et al. 2023

Energy Fuels

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Imbibition after fracturing is an important way of enhancing oil recovery in shale oil reservoirs. It includes three steps: fracturing, huff and puff imbibition, and water flooding. The shale oil reservoir of the Lucaogou Formation in Jimsar Sag was taken as the research object to understand further the mobility of shale oil by imbibition and displacement. First, the porosity, permeability, and wettability of the reservoir were analyzed via experimental methods such as nitrogen permeability porosimetry, automatic mercury porosimetry, microscopic scanning electron microscopy (SEM), and nuclear magnetic resonance technology. The effects of imbibition and displacement processes on various pore sizes were comparatively studied based on the self-absorption method combined with core nuclear magnetic resonance (NMR) to test the wettability. The experimental results show that the reservoir has well-developed micro nano pores and poor pore connectivity. Moreover, the wettability is neutral to oil wetting, and the average pore throat radius distribution is between 0.01 and 0.39 μm. Small (r t < 0.09 μm), medium (0.09 μm < r t < 0.85 μm), and large (r t >0.85 μm) pores account for 42.56%, 28.64%, and 28.8%, respectively. Through pore size conversion, we can know that the lower limits of the fluid utilization radius for the infiltration and displacement processes are 10 and 40 nm, respectively. Therefore, reservoirs with pore distribution between 10 and 40 nm can be exploited through imbibition, while reservoirs above 40 nm are suitable for both imbibition and conventional displacement oil recovery.

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“…Currently, the primary energy source worldwide relies mainly on fossil energy, especially in China, where fossil energy accounts for only about 15% of primary energy consumption. − In the future economic and industrial development, fossil energy will continue to play a crucial role. − Shale gas is an important unconventional natural gas, with China’s shale gas reserves reaching nearly 30 trillion cubic meters, ranking first in the world and being very abundant. − However, the low porosity and permeability of China’s shale gas reservoirs have led to significant development challenges, becoming a key constraint on increasing shale gas production in the country. , Therefore, a certain degree of reservoir stimulation is necessary to promote the high-yield and efficient development of shale gas. − …”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Simulation Research on Controllable Shock Wave-Induced Shale Fracturing under Repeated Action

Ding,

Liu,

Zhang

et al. 2024

ACS Omega

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Low permeability is a key geological factor constraining the development of shale gas, and reservoir modification to improve its permeability is a prerequisite. Controlled shock wave fracturing can induce the formation of complex fractures in reservoirs and is expected to become an important means of reservoir modification. However, the mechanism of controlled shock wave fracturing in shale and the geological engineering control factors are unclear. Therefore, this article reveals the mechanism and effect of shock wave modification through small-scale experiments and large-scale numerical simulations. Results show that as the impact number increases, a significant increase in large fractures and fracture connectivity within the shale samples is observed, while the correlation between the geometric parameters of the fractures and the number of impacts is weak. High-energy input in the model will cause a larger range of damage to the rock, accompanied by a smaller attenuation index, indicating that the speed of energy attenuation plays a decisive role in rock damage. The influence of crustal stress is greater than the speed of energy attenuation, and higher crustal stress will inhibit the formation of fractures. A moderate increase in the number of controllable shock waves is beneficial for the fracturing effect; however, further increasing the loading number of controllable shock waves will weaken the strengthening effect of the fracturing effect.

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Novel method for determining the lower producing limits of pore-throat radius and permeability in tight oil reservoirs

Cited by 14 publications

References 16 publications

Research Status, Existing Problems, and the Prospect of New Methods of Determining the Lower Limit of the Physical Properties of Tight Sandstone Reservoirs

Research Status, Existing Problems, and the Prospect of New Methods of Determining the Lower Limit of the Physical Properties of Tight Sandstone Reservoirs

Evaluation of the Lower Producing Limit of the Pore Radius for Imbibition and Displacement Based on Shale Oil Reservoir Characteristics

Experimental and Numerical Simulation Research on Controllable Shock Wave-Induced Shale Fracturing under Repeated Action

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