Xiao Yan^1,2,3, Di Wang^1,2,4, Haitao Yu^1,2,3,5,*

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.3, pp. 3051-3071, 2024, DOI:10.32604/cmes.2024.051832

Abstract The existence of high-density bedding planes is a typical characteristic of shale oil reservoirs. Understanding the behavior of hydraulic fracturing in high-density laminated rocks is significant for promoting shale oil production. In this study, a hydraulic fracturing model considering tensile failure and frictional slip of the bedding planes is established within the framework of the unified pipe-interface element method (UP-IEM). The model developed for simulating the interaction between the hydraulic fracture and the bedding plane is validated by comparison with experimental results. The hydraulic fracturing patterns in sealed and unsealed bedding planes are compared. Additionally,… More >

Sichen Li^1,2, Dehua Liu^1,2,*, Liang Cheng^1,2, Pan Ma^1,2

Energy Engineering, Vol.121, No.7, pp. 1921-1943, 2024, DOI:10.32604/ee.2024.049906

Abstract Due to the depletion of conventional energy reserves, there has been a global shift towards non-conventional energy sources. Shale oil and gas have emerged as key alternatives. These resources have dense and heterogeneous reservoirs, which require hydraulic fracturing to extract. This process depends on identifying optimal fracturing layers, also known as ‘sweet spots’. However, there is currently no uniform standard for locating these sweet spots. This paper presents a new model for evaluating fracturability that aims to address the current gap in the field. The model utilizes a hierarchical analysis approach and a mutation model, More > Graphic Abstract

Zhengrong Chen^*, Mao Jiang, Chuanzhi Ai, Jianshu Wu, Xin Xie

Energy Engineering, Vol.121, No.6, pp. 1657-1669, 2024, DOI:10.32604/ee.2024.030222

Abstract Based on the actual data collected from the tight sandstone development zone, correlation analysis using the Spearman method was conducted to determine the main factors influencing the gas production rate of tight sandstone fracturing. An integrated model combining geological engineering and numerical simulation of fracture propagation and production was completed. Based on data analysis, the hydraulic fracture parameters were optimized to develop a differentiated fracturing treatment adjustment plan. The results indicate that the influence of geological and engineering factors in the X1 and X2 development zones in the study area differs significantly. Therefore, it is… More >

Rui Zhang¹, Lixiang Wang^2,*, Jing Li^1,4, Chun Feng², Yiming Zhang^1,3,4,*

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.2, pp. 2103-2129, 2024, DOI:10.32604/cmes.2024.049885

Abstract Perforation is a pivotal technique employed to establish main flow channels within the reservoir formation at the outset of hydraulic fracturing operations. Optimizing perforation designs is critical for augmenting the efficacy of hydraulic fracturing and boosting oil or gas production. In this study, we employ a hybrid finite-discrete element method, known as the continuous–discontinuous element method (CDEM), to simulate the initiation of post-perforation hydraulic fractures and to derive enhanced design parameters. The model incorporates the four most prevalent perforation geometries, as delineated in an engineering technical report. Real-world perforations deviate from the ideal cylindrical shape, More >

Diguang Gong¹, Junbin Chen¹, Cheng Cheng², Yuanyuan Kou^2,*

Energy Engineering, Vol.121, No.2, pp. 425-437, 2024, DOI:10.32604/ee.2023.030196

Abstract Horizontal well-stimulation is the key to unconventional resource exploration and development. The development mode of the well plant helps increase the stimulated reservoir volume. Nevertheless, fracture interference between wells reduces the fracturing effect. Here, a 2D hydro-mechanical coupling model describing hydraulic fracture (HF) propagation is established with the extended finite element method, and the effects of several factors on HF propagation during multiple wells fracturing are analyzed. The results show that with an increase in elastic modulus, horizontal principal stress difference and injection fluid displacement, the total fracture area and the reservoir stimulation efficiency are More >

Huaiyin He¹, Longqing Zou¹, Yanchao Li¹, Yixuan Wang¹, Junxiang Li¹, Huan Wen¹, Bei Chang¹, Lijun Liu^2,*

Energy Engineering, Vol.121, No.1, pp. 111-123, 2024, DOI:10.32604/ee.2023.041010

Abstract Multistage multi-cluster hydraulic fracturing has enabled the economic exploitation of shale reservoirs, but the interpretation of hydraulic fracture parameters is challenging. The pressure signals after pump shutdown are influenced by hydraulic fractures, which can reflect the geometric features of hydraulic fracture. The shutdown pressure can be used to interpret the hydraulic fracture parameters in a real-time and cost-effective manner. In this paper, a mathematical model for shutdown pressure evolution is developed considering the effects of wellbore friction, perforation friction and fluid loss in fractures. An efficient numerical simulation method is established by using the method… More >

Yu Gao¹, Zhenqiang Xu^2,3,*, Kaixiang Shen^2,3,*

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.1, pp. 179-192, 2024, DOI:10.32604/fdmp.2023.030499

Abstract Hydraulic jetting is a form of fracturing that involves using a high-pressure jet of water to create fractures in the reservoir rock with a nozzle serving as the central component of the hydraulic sandblasting perforation tool. In this study, the flow behavior of the nozzle is simulated numerically in the framework of a SST k-ω turbulence model. The results show that the nozzle structure can significantly influence the jet performance and related cavitation effect. Through orthogonal experiments, the nozzle geometric parameters are optimized, and the following configuration is found accordingly: contraction angle 20°, contraction segment More >

Sergey Galkin^1,*, Ian Savitckii¹, Denis Shustov¹, Artyom Kukhtinskii¹, Boris Osovetsky², Alexander Votinov³

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.2, pp. 273-284, 2023, DOI:10.32604/fdmp.2022.021697

Abstract Survey and novel research data are used in the present study to classify/identify the lithological type of Verey age reservoirs’ rocks. It is shown how the use of X-ray tomography can clarify the degree of heterogeneity, porosity and permeability of these rocks. These data are then used to elaborate a model of hydraulic fracturing. The resulting software can take into account the properties of proppant and breakdown fluid, thermal reservoir conditions, oil properties, well design data and even the filtration and elastic-mechanical properties of the rocks. Calculations of hydraulic fracturing crack formation are carried out… More > Graphic Abstract

Fang Shi^1,*, Daobing Wang², Xiaogang Chen¹

CMES-Computer Modeling in Engineering & Sciences, Vol.127, No.2, pp. 575-598, 2021, DOI:10.32604/cmes.2021.015384

Abstract Field data suggests that carbonate reservoirs contain abundant natural fractures and cavities. The propagation mechanisms of hydraulic fractures in fracture-cavity reservoirs are different from conventional reservoirs on account of the stress concentration surrounding cavities. In this paper, we develop a fully coupled numerical model using the extended finite element method (XFEM) to investigate the behaviors and propagation mechanisms of hydraulic fractures in fracture-cavity reservoirs. Simulation results show that a higher lateral stress coefficient can enhance the influence of the natural cavity, causing a more curved fracture path. However, lower confining stress or smaller in-situ stress… More >

Daobing Wang¹, Fang Shi^2,*, Hao Qin^1,*, Dongliang Sun¹, Bo Yu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.3, pp. 891-914, 2021, DOI:10.32604/cmes.2021.014206

Abstract In this study, we use the extended finite element method (XFEM) with a consideration of junction enrichment functions to investigate the mechanics of hydraulic fractures related to naturally cemented fractures. In the proposed numerical model, the lubrication equation is adopted to describe the fluid flow within fractures. The fluid-solid coupling systems of the hydraulic fracturing problem are solved using the Newton-Raphson method. The energy release rate criterion is used to determine the cross/arrest behavior between a hydraulic fracture (HF) and a cemented natural fracture (NF). The failure patterns and mechanisms of crack propagation at the… More >