Influence of reservoirs/interlayers thickness on hydraulic fracture propagation laws in low-permeability layered rocks

Yang, Yongming; Li, Xiao; Yang, Xiya; Li, Xiwen

doi:10.1016/j.petrol.2022.111081

Cited by 13 publications

(4 citation statements)

References 29 publications

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“…9 The high injection pressure makes the polymer difficult to inject into the reservoir, and the low sweep efficiency makes it difficult to enter the tiny pore throats, which tends to cause blockage of the low-permeability pore throats, resulting in lower oil recovery. 10 Due to the advantages of low interfacial tension (IFT), wettability alteration effect, and good emulsification effect of crude oil, surfactants are able to reduce the injection pressure and the flowing resistance of oil displacement. 11 Therefore, it becomes an effective method to EOR in low-permeability reservoirs.…”

Section: Introductionmentioning

confidence: 99%

“…However, due to the tiny pore throats and poor flow capacity of the low-permeability reservoir, it is faced with some difficulties such as low single-well production, high injection pressure, high injection energy, and difficulty in establishing an effective displacement system, which leads to the final oil recovery of generally lower than 20%. − The molecular weight of polymer in the tertiary oil recovery is large, and there are some problems when it is used in the low-permeability reservoirs . The high injection pressure makes the polymer difficult to inject into the reservoir, and the low sweep efficiency makes it difficult to enter the tiny pore throats, which tends to cause blockage of the low-permeability pore throats, resulting in lower oil recovery . Due to the advantages of low interfacial tension (IFT), wettability alteration effect, and good emulsification effect of crude oil, surfactants are able to reduce the injection pressure and the flowing resistance of oil displacement .…”

Section: Introductionmentioning

confidence: 99%

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Study on the Adsorption Laws and Enhanced Oil Recovery of Nanofluid Prepared by Amphiphilic Nanosheets in the Low-Permeability Porous Media

Xiao,

Hou

2023

Ind. Eng. Chem. Res.

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The nanofluid prepared by spherical nanoparticles has a good enhanced oil recovery effect in low-permeability reservoirs. However, a huge adsorption loss has been produced in the process of oil displacement, reducing the oil recovery and increasing the production cost. In this paper, the static adsorption experiments under different influence factors, the dynamic desorption experiment on porous media, and the core flooding experiment are carried out with the nanofluids prepared by self-developed amphiphilic nanosheets (ODA-MoS 2 ). Furthermore, the laws of adsorption kinetics and thermodynamics of the ODA-MoS 2 nanofluid on the porous media surfaces are proposed, and the effect on improving oil recovery is clarified ulteriorly. The results show that the physical adsorption of the system on the surface of oil sand is caused by diffusion (concentration difference), electrostatic interaction, and hydrogen bonding. There is a monolayer adsorption existing on the porous media surface, which is consistent with Langmuir isothermal adsorption model. The salinity and temperature have an inhibitory effect on the adsorption of the ODA-MoS 2 nanofluid; the adsorption capacity increases with the increase in concentration and reaches the equilibrium value of 1.68 mg/g at 75 mg/L. Moreover, the adsorption rate of the ODA-MoS 2 nanofluid is the lowest, only 14.71% compared to that of SiO 2 , whereas the oil recovery increases by 18.59% compared to primary water flooding under the concentration of 75 mg/L. Therefore, the ODA-MoS 2 nanofluid with a lower adsorption capacity is more effective in improving oil recovery in low-permeability reservoirs, and it is expected to be applied on a large scale for oil extraction in low-permeability reservoirs.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study on the Adsorption Laws and Enhanced Oil Recovery of Nanofluid Prepared by Amphiphilic Nanosheets in the Low-Permeability Porous Media

Xiao,

Hou

2023

Ind. Eng. Chem. Res.

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“…In the oil and gas industry in particular, a great deal of research [7][8][9] has been carried out into the technology of interlayer explosive fracturing, which has demonstrated the effectiveness of explosive shock waves in inducing rock fracture development. Zhao et al 10 investigated the difference between gas fracturing and hydraulic fracturing and verified that the gas fracturing process can achieve significant efficiency gains in fracturing, Ni et al 11 carried out pulsed hydraulic fracturing experiments and showed that the gas concentration in fractured and pilot wells increased before and after fracturing, and the permeability increased 48-217 times, Yang et al 12 investigated the mechanical damage results of hydraulic fracturing on reservoirs and interbeds using a true triaxial test system, revealing the fracture propagation pattern. The aforementioned outcomes are derived from the utilization of high-energy shockwaves generated by the explosion of solid, liquid, and gaseous explosives to achieve fracture expansion and enhance seepage.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of the in situ gas explosion fracturing and the enhancement of the penetration in coal seam boreholes

Qiao,

Zhang,

Yuan

et al. 2023

Energy Science & Engineering

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Permeability enhancement of low permeability coal seams is a key tool in coal mine gas extraction and utilization. Numerical investigations are used to analyze the geometric parameters of the drilled gas cavity and the effect of initial pressure on explosion parameters to explore the potential of original gas blasting in enhancing crack penetration in coal seams. On the basis of these analyses, the changes in characteristic parameters of the coal body under blasting pressure are examined. The results show that the maximum explosion pressure tends to be close to the theoretical explosion maximum when the L/Φ is 1.67–2.5, and the mechanical effect of the explosion pressure and surge velocity on the wall reaches the optimum in the experimental group when the L/Φ is 1.67. The initial pressure and the maximum explosion pressure demonstrate a linear positive correlation, and increasing the former can effectively enhance the force applied to the hole wall. During the gas explosion pressurization stage, the cracking range of coal under pressure is 0.05 m, but the duration of peak pressure can extend the range of cracking. The combined effect of the stress and pressure fields causes elastic energy storage in the coal body to fail in the radial region of the hole wall, but regains elastic energy storage as the pressure increases. The effect of fracturing on the radial coal seam permeability of the borehole wall before and after the fracturing effect is expanded by 19.6 times, proving that in situ gas explosion in boreholes can effectively improve the gas seepage characteristics of coal seams and increase the gas recovery rate. The simulations indicate that the application of in situ gas explosion fracturing and permeation technology is limited by the increase in maximum explosion pressure and the cumulative effect time of the peak pressure. This provides a theoretical basis for understanding the constraints of gas explosion fracturing and permeation technology.

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“…Currently, hydrofracturing is an important development technology for unconventional reservoirs with low permeability . Therefore, understanding the spatial distribution law, propagation mode, and key influencing factors of hydraulic fractures in low-permeability reservoirs under the coupled effect of in situ stress and hydraulic pressure is crucial to effectively implement hydrofracturing technology and improve the recovery efficiency of unconventional oil and gas resources. − The propagation processes and laws of hydraulic fracture propagation in low-permeability reservoirs are extremely complicated as a result of the stratum property difference between the depth and complexity of the in situ stress environment. The reservoir rock is buried deep underground, and it is difficult to effectively monitor the behavior of hydraulic fracture propagation in the field.…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of Hydraulic Fracture Propagation and Multi-well Effect during Multiple Vertical Well Fracturing in Layered Reservoirs with Low Permeability

Yang,

Li,

et al. 2023

Energy Fuels

Self Cite

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Segmental-layered modeling and fine grid division methods were proposed to construct a three-dimensional largescale layered geologic model and reveal the mechanisms of hydraulic fracture propagation and the well spacing effect in multi-well fracturing in layered reservoirs with low permeability. The hydraulic fracture propagation in layered reservoirs under multi-well fracturing was simulated using a continuum-based discrete element numerical method. The effects of the stratum property difference, in situ horizontal stress difference (HSD), and well spacing on breakdown pressures and fracture propagation were analyzed. The concept of "extension ellipse" was proposed to describe the propagation morphology of fractures, which addresses the difficulty of accurately characterizing the propagation morphology of fractures at the geologic scale. The influence range of the multiwell effect in layered reservoirs was also determined, and the effect mechanisms of stress amplification and attraction and repulsion between fractures on the behavior of hydraulic fracture propagation were revealed. Layered reservoirs and higher in situ HSD restrict the development of hydraulic fractures but greatly reduce the breakdown pressures. The multi-well fracturing mode changes the stress field distribution around the wells and weakens the effects of in situ HSD on fracture propagation. In comparison to homogeneous reservoirs, the range of the multi-well effect in the layered reservoirs is relatively small. At the fracturing site, the well spacing should be appropriately increased in the direction of the maximum horizontal stress and should be reduced in the direction of minimum horizontal stress, helping hydraulic fracture development and improving the fracturing stimulation effect in layered reservoirs. This study addresses the deficiency of considering stratum property differences in the existing large-scale fracturing models, and the results provide a reference for the optimization and design of fracturing simulation in the layered reservoirs with low permeability.

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Influence of reservoirs/interlayers thickness on hydraulic fracture propagation laws in low-permeability layered rocks

Cited by 13 publications

References 29 publications

Study on the Adsorption Laws and Enhanced Oil Recovery of Nanofluid Prepared by Amphiphilic Nanosheets in the Low-Permeability Porous Media

Study on the Adsorption Laws and Enhanced Oil Recovery of Nanofluid Prepared by Amphiphilic Nanosheets in the Low-Permeability Porous Media

Numerical investigation of the in situ gas explosion fracturing and the enhancement of the penetration in coal seam boreholes

Mechanisms of Hydraulic Fracture Propagation and Multi-well Effect during Multiple Vertical Well Fracturing in Layered Reservoirs with Low Permeability

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