Effect of Natural Fractures on Wormhole-Propagation Behavior

Mou, Jianye; Yu, Xiaoshan; Wang, Lei; Zhang, Shicheng; Ma, Xinfang; Lyu, Xinrun

doi:10.2118/191148-pa

Cited by 7 publications

(2 citation statements)

References 29 publications

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“…Matrix acidizing is a highly effective and indispensable technology for economically developing carbonate reservoirs. It involves injectin acid fluids, such as hydrochloric acid, thickened acid, or foam acid, into the formation below fracture pressure to dissolve carbonate minerals, creating acid wormholes that penetrate contamination zones, communicate with distant reservoirs and natural fractures, and restore oil and gas well productivity [5][6][7]. The success of acidizing operations depends on the ability to distribute the acid uniformly in the reservoir.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Wormhole Propagation with Foamed-Viscoelastic-Surfactant Acid in Carbonate Acidizing

et al. 2023

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Successful matrix acidizing for extremely thick carbonate reservoirs with long horizontal well sections and strong heterogeneity requires efficient temporary plugging and diverting of acid fluid, ensuring acid fluid distribution to each production layer. Foamed-viscoelastic-surfactant (Foamed-VES) acid combines the benefits of both foam acid and viscoelastic surfactant (VES) acid, integrating foam plugging and viscous plugging. It can achieve uniform acid distribution in highly heterogeneous reservoirs. However, little research has been conducted on the wormhole propagation law of foamed-VES acid. To address this gap, this study established a mathematical model of foamed-VES acid wormhole propagation based on the dual-scale model. The model was coupled with a random porosity distribution generated with geological statistical software. The effects of different factors on foamed-VES acid etching were simulated. Numerical results show that foamed-VES acid can stimulate low-permeability reservoirs with a permeability differential of 20. Its inherent mechanism lies in the synergy of foam plugging and VES viscous plugging. This study enhances our understanding of the acid diversion mechanism of foamed-VES acid, providing a theoretical foundation for on-site acidizing treatment.

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Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Wormhole Propagation with Foamed-Viscoelastic-Surfactant Acid in Carbonate Acidizing

et al. 2023

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“…The injected acid penetrates the formation guided by the fractures, increasing the permeability of the formation. The productivity enhancement effect of acidization on fractured carbonate reservoirs is usually greater than that on nonfractured reservoirs [33][34][35]. Natural fractures have considerable effects on the acid distribution and wormhole propagation.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of the Wormhole Propagation in Fractured Carbonate Rocks during Acidization Using a Thermal-Hydrologic-Mechanics-Chemical Coupled Model

Liu

Huang

Jia

et al. 2022

Water

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Acidizing is a widely adopted approach for stimulating carbonate reservoirs. The two-scale continuum (TSC) model is the most widely used model for simulating the reactive process in a carbonate reservoir during acidizing. In realistic cases, there are overburden pressure and pore pressure at present. When the injected acid reacts with the rock, the dissolution of the rock and the consumption of the acid in the pore will break the mechanical balance of the rock. Many experimental studies show that cores after acidizing have lower strength. However, it is still not clear how the deformation of rocks by the change of ground stress influences the acidizing dynamics. For fractured carbonate reservoirs, fractures play a leading role in the flow of injected acid, which preferentially flows into the fractures and dissolves the fracture walls. The effect of the combined action of rock mechanical balance broken and fracture wall dissolution on the formation of wormholes in fractured carbonate reservoirs remains to be studied. To address the above-mentioned issues, a thermal-hydrologic-mechanical-chemical coupled model is presented based on the TSC model for studying the wormhole propagation in fractured carbonate reservoirs under practical conditions. Linear and radial flow cases are simulated to investigate the influences of fracture distribution, reaction temperature, and effective stress on acidizing dynamics. The simulation results show that more wormhole branches are formed by acidizing if the fractures are perpendicular to the flow direction of acid. Temperature is a key parameter affecting the acidification dissolution patterns, so the influence of temperature cannot be ignored during the acidification design. As the effective stress of the formation increases, the diameter of the wormhole gradually decreases, and the branching decreases. More acid is needed for the same stimulation result under higher effective stress.

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Quasi-3D fracture acidizing simulation based on discrete virtual internal bond method

Zhu,

Zhao,

Zhang

2024

Computers and Geotechnics

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Effect of Natural Fractures on Wormhole-Propagation Behavior

Cited by 7 publications

References 29 publications

Numerical Simulation of Wormhole Propagation with Foamed-Viscoelastic-Surfactant Acid in Carbonate Acidizing

Numerical Simulation of Wormhole Propagation with Foamed-Viscoelastic-Surfactant Acid in Carbonate Acidizing

Numerical Simulation of the Wormhole Propagation in Fractured Carbonate Rocks during Acidization Using a Thermal-Hydrologic-Mechanics-Chemical Coupled Model

Quasi-3D fracture acidizing simulation based on discrete virtual internal bond method

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