Experimental and Numerical Investigation of Multiscale Fracture Deformation in Fractured–Vuggy Carbonate Reservoirs

Li, Song; Kang, Yili; You, Lijun; Li, Daqi; Lian, Zhanghua

doi:10.1007/s13369-014-1018-6

Cited by 20 publications

(13 citation statements)

References 13 publications

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“…The development of the stratification plane, pump pressure and stress state had a significant impact on the fracture morphology. Jin et al (2009), Li et al (2009), Zhang et al (2010) and Li et al (2014) simulated hydraulic fracture propagation in fractured vuggy carbonate reservoirs using the damage mechanics method. The results demonstrated that the tortuous diversion conditions of the hydraulic fracture depended on the angle between the maximum horizontal principal stress and natural fracture and the scale of the fracture-cave cube.…”

Section: Pore Elasticity Effect and Reorientationmentioning

confidence: 99%

An experimental study on the mechanism of degradable fiber-assisted diverting fracturing and its influencing factors

Wang

Zhou

et al. 2015

Journal of Natural Gas Science and Engineering

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Fiber-laden fluid systems have been successfully applied for reorientation fracturing in tight gas and shale gas reservoirs around the world. Although many successful cases have been reported in the literature, there is a lack of a deep understanding of the mechanical mechanism of fiber-assisted diverting fracturing. Hence, this paper presents a systematic study of the fracture diversion mechanisms of the fiber-diverting fracturing technique. A series of laboratory experiments is conducted with a real tri-axial stress simulation system. Degradable fibers are applied to large-size natural outcrop samples (300 mm × 300 mm × 300 mm) under true triaxial stress conditions. The dynamic filtration experiment to test the temporary plugging ability showed that the fractures were effectively plugged by fiber fluids. A variety of factors related to the fracture reorientation are tested and compared, including injection rate, fracture width and horizontal principal stress difference. The additional pressure drop caused by the fiber filtration cake is calculated and used to quantitatively analyze the effects on fracture reorientation. The net pressure increase is the driving force of the fracture diversion and formation of the fracture network. The conclusions were used to guide carbonate reservoir stimulations in the Tarim oil field, in northwest China. The phenomenon of fracture diversion was evident as the pumping pressure increased considerably after injecting the degradable fiber. The hydraulic fracturing treatment and production results showed substantial pressure responses and excellent hydrocarbon production.

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Section: Pore Elasticity Effect and Reorientationmentioning

confidence: 99%

An experimental study on the mechanism of degradable fiber-assisted diverting fracturing and its influencing factors

Wang

Zhou

et al. 2015

Journal of Natural Gas Science and Engineering

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“…Subsequently, Ma et al [18] applied the unified pipe network to establish a 3D dual-phase acidizing model for simulation of propagation of acidizing wormholes in the fractured carbonate formation, and obtained the solution by sequential implicit time and adaptive time step methods. Li et al [19] studied fracture deformation and pressure distribution within a fracture in ANSYS software, and found that the NF intersected with the wellbore are very sensitive to pressure fluctuation within the wellbore and cause fluid leakoff in completion operation. Luo et al [20] established an XFEM model by considering the effects of mechanical deformation, fluid flow, acid-rock reaction, vugs, NFs, and acid on HF propagation and performed a simulation of propagation of acid-etched fractures in fractured-vuggy carbonate rock.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation on Hydrofracture Propagation in Fractured-Vuggy Unconventional Reservoirs

et al. 2022

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The unconventional reservoirs such as carbonate formation develops complex and diverse storage space structures, and it is composed of large-scale cavity, dissolved vug, and fractures. The carbonate reservoir is highly heterogeneous. Acid fracturing of carbonate reservoir is completed through the complex mechanical mechanism of interaction between vug and hydraulic fracture (HF). We use the equivalent method of reducing the rock strength by acid etching and serious fluid leakoff during interaction of HF and vug to establish a finite element (FE) model of HF propagation during acid fracturing in the fractured-vuggy carbonate reservoir. The model considers the effect of serious fluid leakoff during interaction between HF and vug, mechanism of interaction between HFs and the fracture-vug system, and change in acid etching intensity. Then, we carry out numerical simulation on impacts of injection rate, fluid viscosity, leakoff behavior in fractures and vugs, and natural fracture (NF) approaching angle on HF propagation in acid fracturing and compare the characteristics of injection pressure, fracture pressure, and HF size. It is suggested that the acid fracturing treatment should be operated by increasing the acid solution viscosity to reduce fluid leakoff, injecting fracturing fluid and acid fluid alternatively, increasing injection rate, and injecting fibers and ceramics when small pressure drop occurs during the HF interacts with the fracture-vug. When a large pressure drop occurs, it is suggested that the middle-low viscosity acid be injected at a low rate to etch the carbonate rock and enhance the fracture conductivity. HF propagates under higher pressure when the NF approaching angle is smaller.

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“…The reserves of carbonate reservoirs account for half of the world's total oil reserves. Oil production of carbonate reservoirs accounts for 60% of the world's total oil production [1][2][3]. In China, carbonate reservoirs have been discovered in Bohai Bay, Ordos, Sichuan, and Tarim basins [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation and Experimental Studies of Karst Caves Collapse Mechanism in Fractured-Vuggy Reservoirs

Guo

Wang

Sun³

et al. 2020

Geofluids

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Karst cave collapse usually occurs during the process of drilling and reservoir development. Karst cave collapse increases drilling risk and seriously affects oil production. In order to reveal the collapse mechanism of karst caves in fractured-vuggy reservoirs in Tahe oil field, rock mechanic experiments and numerical simulation studies were conducted. In rock mechanic experiments, three types of rock mechanics tests (uniaxial compression, triaxial compression, and Brazilian splitting) were carried out to obtain the basic rock mechanics parameters. In numerical simulation studies, the collapse conditions of a single karst cave and a cave system were studied. Numerical simulation results indicate that for a single karst cave, the size and geometrical features of karst caves are the main factors influencing collapse condition. For a cave system, a combination pattern and distance between caves are two main factors affecting collapse condition. In order to facilitate the application of these research results, the authors present formulas for calculating the critical conditions of karst cave collapse by means of multivariate linear regression method. The calculation formulas and prediction chart were verified as consistent with actual field results. The research results in this paper have great theoretical and practical value for revealing the mechanism of karst cave collapse in fractured-vuggy carbonate reservoirs.

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Experimental and Numerical Investigation of Multiscale Fracture Deformation in Fractured–Vuggy Carbonate Reservoirs

Cited by 20 publications

References 13 publications

An experimental study on the mechanism of degradable fiber-assisted diverting fracturing and its influencing factors

An experimental study on the mechanism of degradable fiber-assisted diverting fracturing and its influencing factors

Numerical Simulation on Hydrofracture Propagation in Fractured-Vuggy Unconventional Reservoirs

Numerical Simulation and Experimental Studies of Karst Caves Collapse Mechanism in Fractured-Vuggy Reservoirs

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