Yuanyuan Yang¹, Xian Shi^1,2,*, Cheng Ji³, Yujie Yan³, Na An³, Teng Zhang⁴

Energy Engineering, Vol.121, No.12, pp. 3667-3688, 2024, DOI:10.32604/ee.2024.056266 - 22 November 2024

Abstract Based on a geology-engineering sweet spot evaluation, the high-quality reservoir zones and horizontal well landing points were determined. Subsequently, fracture propagation and production were simulated with a multilayer fracturing scenario. The optimal hydraulic fracturing strategy for the multilayer fracturing network was determined by introducing a vertical asymmetry factor. This strategy aimed to minimize stress shadowing effects in the vertical direction while maximizing the stimulated reservoir volume (SRV). The study found that the small vertical layer spacing of high-quality reservoirs and the presence of stress-masking layers (with a stress difference of approximately 3~8 MPa) indicate that… More > Graphic Abstract

Shangjun Gao^1,2, Yang Yang¹, Man Chen¹, Jian Zheng¹, Luqi Qin^2,*, Xiangyu Liu², Jianying Yang¹

Energy Engineering, Vol.121, No.11, pp. 3305-3329, 2024, DOI:10.32604/ee.2024.053622 - 21 October 2024

Abstract Horizontal well drilling and multi-stage hydraulic fracturing are key technologies for the development of shale gas reservoirs. Instantaneous acquisition of hydraulic fracture parameters is crucial for evaluating fracturing effectiveness, optimizing processes, and predicting gas productivity. This paper establishes a transient flow model for shale gas wells based on the boundary element method, achieving the characterization of stimulated reservoir volume for a single stage. By integrating pressure monitoring data following the pumping shut-in period of hydraulic fracturing for well testing interpretation, a workflow for inverting fracture parameters of shale gas wells is established. This new method… More >

Boyu Liu¹, Jun Yao^1,*, Hai Sun¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.29, No.1, pp. 1-1, 2024, DOI:10.32604/icces.2024.011600

Abstract The temperature gradient between the geological formation and the injected supercritical CO₂ (Sc-CO₂) initiates heat transfer processes, leading to a non-uniform temperature field within the fracture. This spatial thermal variation induces fluctuations in the density and viscosity of Sc-CO₂. Moreover, the non-uniform density distribution of Sc-CO₂ leads to varying degrees of volume expansion or shrinkage, influencing fluid flow velocities within the fractures. This study integrates heat transfer and fluid leak-off models into the Eulerian-Eulerian two-fluid framework to systematically investigate the collective impacts of Sc-CO₂'s density, viscosity, and density-induced volumetric alterations on the proppant transport process under varied pumping… More >

Hong Dong¹, Xiding Gao^2,*, Xinqi Zhang¹, Qian Wang^1,3, Haipeng Xu¹, Binrui Wang², Chengguo Gao¹, Kaiwen Luo², Hengyi Jiang²

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.9, pp. 1971-1991, 2024, DOI:10.32604/fdmp.2024.049406 - 23 August 2024

Abstract CO₂ pre-injection during hydraulic fracturing is an important method for the development of medium to deep heavy oil reservoirs. It reduces the interfacial tension and viscosity of crude oil, enhances its flowability, maintains reservoir pressure, and increases reservoir drainage capacity. Taking the Badaowan Formation as an example, in this study a detailed three-dimensional geomechanical model based on static data from well logging interpretations is elaborated, which can take into account both vertical and horizontal geological variations and mechanical characteristics. A comprehensive analysis of the impact of key construction parameters on Pre-CO₂ based fracturing (such as cluster More >

Qiuyang Cheng^1,2,3, Lijun You^3,*, Cheng Chang^1,2, Weiyang Xie^1,2, Haoran Hu^1,2, Xingchen Wang^1,2

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.7, pp. 1441-1462, 2024, DOI:10.32604/fdmp.2024.051200 - 23 July 2024

Abstract Horizontal well drilling and multi-stage hydraulic fracturing technologies are at the root of commercial shale gas development and exploitation. During these processes, typically, a large amount of working fluid enters the formation, resulting in widespread water-rock interaction. Deeply understanding such effects is required to optimize the production system. In this study, the mechanisms of water-rock interaction and the associated responses of shale fabric are systematically reviewed for working fluids such as neutral fluids, acid fluids, alkali fluids and oxidative fluids. It is shown that shale is generally rich in water-sensitive components such as clay minerals,… More >

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 - 08 July 2024

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 - 11 June 2024

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 - 21 May 2024

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 - 20 May 2024

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 - 25 January 2024

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 >