Dense sandstone formation is a common difficult-to-drill section in oil and gas drilling, and its difficult-to-drill nature lies in the complex composition of rock minerals and dense cementation, coupled with the multiscale interaction of in situ temperature and pressure coupling in the endowment environment, which makes its mechanical characteristics more complex and difficult to be effectively characterized by existing experimental means. For this reason, starting from the fine-scale thermal expansion characteristics of the skeleton/cemented minerals, combined with the polycrystalline discrete element method, a non-homogeneous fine-scale mechanical modeling method considering the temperature effect was established and used to reveal its triaxial compression characteristics. The results show these as follows. Unlike the thermal expansion and contraction characteristics of skeleton minerals, the spacing of clay mineral grain surfaces shows irreversible thermal expansion with increasing temperature, which is the fundamental reason for the mechanical properties of locally strengthened dense sandstones; the thermal expansion of clay minerals increases the contact strength of intergranularity, and the localized densification makes the intergranularity more difficult to be damaged during triaxial compression, and the percentage of intragranular tensile cracks rises with the temperature; the compressive strength and elastic modulus of clay minerals increase with the temperature at room temperature~200 ℃, compressive strength and modulus of elasticity increases with temperature, the increase of peripheral pressure makes the elastic modulus growth trend from “lower convex” to “upper convex”. 30 MPa, room temperature to 200 ℃, the compressive strength increased by 21.6%. At 200 ℃, the compressive strength increased by 26.6% from 0.1 to 30 MPa. The results provide a theoretical tool for prediction of pre-drilling mechanics for drilling wells in deep dense sandstones.
ZHU Yan, LI Gao, YANG Xu, ZHANG Yi, LI Hong-tao.
Discrete Element Simulation of Triaxial Compressive Damage Characteristics of Sandstone under Temperature-pressure Coupling[J].
Science Technology and Engineering, 2026, 26(3): 989-998 DOI:10.12404/j.issn.1671-1815.2501049
随着计算机技术的进步,数值模拟方法已成为研究岩石力学性质的重要工具。付腾飞等[7]基于离散元模型从细观尺度对砂岩在不同围压下的损伤演化进行模拟分析。潘海潮等[8]针对离散元软件中细观参数标定困难的难题,提出了一种基于机器学习算法的空心圆柱砂岩离散元细观参数标定方法。陈旭等[9]利用离散元法建立砂岩颗粒流数值模型,开展4种不同法向应力条件下的直剪渗流模拟研究。徐超华等[10]以单轴压缩和巴西劈裂试验为基础,利用PFC3D软件得到细观参数与宏观力学参数的线性关系式。Wang等 [11]开展了巴西劈裂、三轴压缩试验,验证了宏-微观参数的转换关系,建立了PFC2D水力压裂数值模型。Meharn等[12]采用离散元方法(discrete element method,DEM)法模拟了各向异性砂岩的强度、变形和破裂行为。然而,目前大多数学者在砂岩数值模型构建过程中,未考虑黏土矿物的分布与热学参数。对于砂岩来讲,骨架矿物与黏土矿物的热敏感性存在差异,在建模过程中应特别考虑黏土矿物的分布与热学参数。
GuoChunfen, LiAirong, FanWanhong, et al. Micro-pore structure of tight sandstone reservoir and influence on reservoir physical properties: Chang 6 Member of Huangling Area, Ordos Basin as an example[J]. Science Technology and Engineering, 2024, 24(34): 14623-14631.
HouBing, WuAnan, ChangZhi, et al. Experimental tudy on vertical propagation of fractures of multi-sweet of spots shale oil reservoir[J]. Chinese Journal of Geotechnical Engineering, 2021, 43(7): 1322-1330.
YuXin, LiGao, ChenZe. Changes in uniaxial compressive strength during heating of dense sandstone[J]. Science Technology and Engineering, 2019, 19(32): 133-138.
DaiYuhang, LiuJianfeng, LinHao, et al. Mechanical properties and acoustic emission evolution of layeredshale under triaxial compression[J]. Science Technology and Engineering, 2024, 24(24): 10419-10428.
HanZhongying, SunBo, WangYunhan, eral. Rock mechanics experiments of deep sandstone and influence rules of sand production in reservoir exploitation[J]. Science Technology and Engineering, 2023, 23(29): 12504-12512.
[11]
KhalilR, EmadiH. An experimental investigation of cryogenic treatments effects on porosity, permeability, and mechanical properties of Marcellus downhole core samples[J]. Journal of Natural Gas Science and Engineering, 2020, 81: 1875-5100.
FuTengfei, XuTao, ZhuWangcheng, et al. Damage characteristics of sandstone under triaxial compression based on polycrystalline discrete element method[J]. Journal of Northeastern University(Natural Science), 2020, 41(7): 968-974.
PanHaichao, WuJinghong, JiangYue, et al. Calibration method for mesoscopic parameters of hollow cylindrical sandstone discrete element based on machine learning algorithm[J]. Science Technology and Engineering, 2025, 25(1): 339-345.
ChenXu, YuFeiyang, TangMinggao, et al. DEM simulation of progressive damage and permeability evolution of sandstone during direct-shearing[J]. Chinese Journal of Rock Mechanics and Engineering, 2024, 43(S1): 3161-3174.
XuChaohua, ZhangBo, QinXiaohui, et al. Mesoscopic parameter calibration of PFC3D numerical model based on PB + CCD design method[J]. Science Technology and Engineering, 2024, 24(31): 13512-13520.
[20]
WangH J, GongW L, YuanG X, et al. Effect of in-situ stress on hydraulic fracturing of tight sandstone based on discrete element method[J]. Energies, 2022, 15(15): 5620-5620.
[21]
MehranN, GholamrezaK, VahabS, et al. An experimental and numerical study of layered sandstone’s anisotropic behaviour under compressive and tensile stress conditions[J]. Rock Mechanics and Rock Engineering, 2023, 57(2): 1451-1470.
ZhangLi, ShuZhiguo, HeSheng, et al. Reservoir characteristics and differential evolution process of Xujiahe Formation in Jiannan Area, East Sichuan[J]. Earth Science, 2021, 46(9): 3139-3156.
ZhangYi, LiGao, WangXiyong, et al. Microfabric characteristics of tight sandstone of Xujiahe Formation in Western Sichuan after high temperature and the effect on mechanical properties[J]. Chinese Journal of Rock Mechanics and Engineering, 2021, 40(11): 2249-2259.
[26]
YangX, ZhangY, LiG, et al. Mesoscopic modeling approach and application based on rock thin slices and nanoindentation[J]. Computers and Geotechnics, 2024, 165: 0266-352 X.
CheJiaqi, WangHanxiang, ZhangYanwen, et al. Heat production law and temperature control method of milling tools for workover under action of thermo-mechanical coupling[J]. Journal of China University of Petroleum(Edition of Natural Science), 2023, 47(3): 132-141.
[29]
MaZ Y, ZhangC P, RanjithG P, et al. Uncovering the creep deformation mechanism of rock-forming minerals using nanoindentation[J]. International Journal of Mining Science and Technology, 2022, 32(2): 283-294.
ZhangChenhan, YouShuang, JiHongguang. Grain-based model and analysis of deep hard rock considering intragranular structure characteristics of mineral[J]. Journal of China Coal Society, 2021, 46(S2): 749-758.
[32]
WangF, KonietzkY, MartinH, et al. Thermal cracking in granite during a heating-cooling cycle up to 1 000 ℃: laboratory testing and real-time simulation[J]. Rock Mechanics and Rock Engineering, 2022, 55(3): 1-18.
ZhangWeiwei, LiYanrong, GongYangqing, et al. Effects of temperature fluctation on structural evolution of inital loess deposits[J]. Journal of Engineering Geology, 2022, 30(2): 357-365.
[35]
SwainK A. Influence of thermal conductivity of rocks on polar ice sheet recession near Schirmacher Oasis, East Antarctica[J]. Journal of the Geological Society of India, 2019, 93(4): 455-465.
[36]
LiliestimernaA. Thermal classification of cable route[D]. Gothenburg: Chalmers University of Technology, 2015.
[37]
KumarS, KumarA. Indirect tensile test modelling for inhomogeneous rock samples using digital image processing[J]. Arabian Journal of Geosciences, 2023, 16(8): 1866-7511.
GuoJinping, YangYanguang, ZhangWen, et al. Experimental study on dynamic damage and failure characteristics of blue sandstone after high temperature[J]. Journal of Henan Polytechnic University(Natural Science), 2023, 42(2): 160-165.
[40]
GuoP Y, BuM H, ZhangP, et al. Mechanical properties and crack propagation behavior of granite after high temperature treatment based on a thermo-mechanical grain-based model[J]. Rock Mechanics and Rock Engineering, 2023, 56(9): 6411-6435.
GongJiachen, ChenShihai. Experimental study on mechanical parameters and wave velocity variation of sandstone under high ground stress[J]. Journal of Shandong University(Engineering Science), 2020, 50(3): 82-87, 97.