首页|天然气水合物注热分解诱发储层变形破坏的正交数值模拟研究

天然气水合物注热分解诱发储层变形破坏的正交数值模拟研究

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针对天然气水合物热分解而引起的储层失稳破坏机理及影响因素不明确的问题,考虑因水合物热分解引起的地层传热、孔隙流体渗流和固体骨架的变形破坏,建立了水合物沉积层的热-流-固耦合模型及其作用下储层固体骨架的弹塑性本构模型.基于ABAQUS软件的USD-FLD子程序进行二次开发,开展正交实验数值模拟,分析注热温度差、水合物沉积层的绝对渗透率和有效主应力差对水合物沉积层近井储层变形破坏影响的敏感性及影响机理.结果表明:对近井储层变形破坏影响的敏感程度由大到小依次为有效主应力差、绝对渗透率、注热温度差;水合物热分解引起的近井储层力学性质劣化和有效应力下降是导致其发生变形破坏的主要原因;有效主应力差越大,等效塑性应变最大值越大,并且受水平地应力非均匀性的影响,近井储层变形破坏最严重的位置始终位于井眼最小水平地应力方向上.该研究成果可为热激法开采天然气水合物或含水合物地层的钻井作业提供借鉴.
Qrthogonal Numerical Simulation Study of the Reservoir Deformation Damage Induced by the Thermal Injection Decomposition of Natural Gas Hydrate
In response to the problem that the damage mechanism and influencing factors of the reservoir destabiliza-tion caused by the thermal decomposition of natural gas hydrate are not clear,the coupled heat-fluid-solid model of the hydrate deposition layer and the elastic-plasticity intrinsic model of the solid skeleton of the reservoir under the action of such coupled model have been established in consideration of the formation heat transfer,pore fluid seep-age and deformation damage of solid skeleton due to the thermal decomposition of hydrate.Based on the secondary development of the USDFLD subroutine of ABAQUS software,the orthogonal numerical simulation experiments were carried out to analyze the sensitivity of the thermal injection temperature difference,the absolute permeability of the hydrate deposition layer,and the effective principal stress difference to the influence of the deformation damage of near-well reservoir in the the hydrate deposition layer and the influence mechanism.The results show that the sen-sitivity to the influence of the deformation damage of near-well reservoir is in descending order of the effective prin-cipal stress difference,absolute permeability,and thermal injection temperature difference;the deterioration of the mechanical properties of the near-well reservoir and the decrease of the effective stress caused by the thermal de-composition of hydrate are the main reasons for the deformation damage;the larger the effective principal stress difference is,the larger the maximum value of the equivalent plastic strain is,and the location of the most severe deformation damage in the near-well reservoir is always located in the direction of the minimum horizontal geostress in the borehole under the influence of the the non-uniformity of the horizontal geostress.This study provides a ref-erence for the natural gas hydrate extraction with the thermal stimulation method and drilling operations of hydrate-bearing formations.

natural gas hydratethermal injection decompositionthermo-hydro-mechanical coupled modelelas-to-plastic constitutive modelorthogonal numerical simulationmaximum equivalent plastic strain

翟诚、吴迪、秦冬冬

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山西工程技术学院,山西阳泉 045000

山西工程技术学院矿区生态修复与固废资源化省市共建山西省重点实验室培育基地,山西阳泉 045000

辽宁工程技术大学,辽宁阜新 123000

天然气水合物 注热分解 热-流-固耦合模型 弹塑性本构模型 正交数值模拟 等效塑性应变最大值

国家自然科学基金&&山西工程技术学院教师科研启动基金博士毕业生、博士后研究人员来晋工作奖励经费项目(第二批)(2021)

51974147521041402021QD-022021PT-13

2024

10.3969/j.issn.1006-6535.2024.02.013

特种油气藏
中油辽河油田公司

特种油气藏

CSTPCD北大核心
影响因子：1.626
ISSN：1006-6535
年,卷(期)：2024.31(2)
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