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| 高温环境下油井水泥石力学性能试验 |
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王磊1,2,曾义金1,3,张青庆4,徐峰1,2,杨春和1,2,5,郭印同1,2,陶谦1,3,刘杰5
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(1.页岩油气富集机理与有效开发国家重点实验室,北京 100101;2.中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉 430071;3.中国石油化工股份有限公司石油工程技术研究院,北京 100101;4.中国石油管道有限责任公司西气东输分公司,上海 200122;5.重庆大学煤矿灾害动力学与控制国家重点实验室,重庆 400044)
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| 摘要: |
| 油井水泥石通常在地层深部高温环境下服役,其力学性能对于油气井的固井质量以及后续水力压裂施工有重要影响。按照深井高温油气井所用的常规水泥浆体系配方,在温度130 ℃、压力20.7 MPa的养护环境下,制备标准圆柱体水泥试样,开展常温单轴压缩试验,常温、80 ℃、130 ℃条件下的三轴压缩和循环加卸载试验,探究油井水泥石在高温下的强度、变形、破坏模式等特征。结果表明:常温下水泥石表现出显著的弹脆性特征,水泥石破坏后形成宏观裂缝;在80 ℃下水泥石的抗压强度没有明显减弱,弹性模量相对于常温下降低了11.1％;在130 ℃下水泥石的抗压强度和弹性模量均显著降低,相对于常温下分别下降17.4％和47.6％;80和130 ℃下水泥石的变形均以轴向压缩变形为主,侧向膨胀较小,不易形成明显宏观裂缝,表现出良好的抵抗变形破坏的能力,具有近似线弹性-理想塑性的特征;80和130 ℃下对水泥石的循环加卸载产生的塑性变形分别为0.9773％和0.5649％,是常温下的2.26倍和1.31倍,塑性变形主要形成于第1个加卸载循环。 |
| 关键词: 固井 水泥石 高温 循环荷载 力学性能 |
| DOI：10.3969/j.issn.1673-5005.2018.06.010 |
| 分类号::TE 256 |
| 文献标识码:A |
| 基金项目:国家自然科学基金项目(51574218)；国家科技重大专项(2016ZX05060017,2017ZX05036003004) |
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| Experimental study on mechanical properties of oil well cement under high temperature |
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WANG Lei1,2, ZENG Yijin1,3, ZHANG Qingqing4, XU Feng1,2, YANG Chunhe1,2,5, GUO Yintong1,2, TAO Qian1,3, LIU Jie5
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(1.State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing 100101, China;2.State Key Laboratory of Geomechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China;3.SINOPEC Research Institute of Petroleum Engineering, Beijing 100101, China;4.West-East Gas Pipeline Company, China Petroleum Pipeline Company Limited, Shanghai 200122,China;5.State Key Laboratory for Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China)
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| Abstract: |
| Oil and gas well cement works in deep underground environment at high temperature and high pressure conditions, and its mechanical property is of great importance to the cementation quality of the wellbore and successive oil and gas production and hydraulic fracturing. In this study, The mechanical properties of the cementing materials commonly used in high temperature wells were tested. Standard cylinder cement stone specimens were prepared according to the required formulation of cement slurry system and maintained at 130 ℃ and 20.7 MPa. Then, uniaxial compression, triaxial compression and triaxial cyclic loading testings were conducted at room temperature, 80 ℃ and 130 ℃ to investigate the strength, deformation and fracture mode of the cement specimen. The experimental results indicate that the cement specimens are of typical elastic-brittle feature at room temperature, and macro-fractures can be formed during their destruction. At 80 ℃, the strength of the cement specimen can be maintained as same as that at room temperature, but its elastic modulus can be reduced by over 11％. At 130 ℃, its strength and elastic modulus decreases by 17.4％ and 47.6％, respectively. At 80 ℃ and 130 ℃, the deformation of the specimen is mainly due to axial compression, while lateral dilation is relatively small, and macro-fractures are unlikely to occur. The cement stone shows favorable performance on resisting deformation and destruction and can be regarded as a near linear elastic and good plastic material. Its plastic strain caused by cycle loading at 80 ℃ and 130 ℃ are of 0.9773％ and 0.5649％, respectively, 2.26 and 1.31 times of that at room temperature, and mainly from the first loading cycle. |
| Key words: well cementation cement stone high temperature cyclic loading mechanical property |
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