储气库注采载荷对储层段水泥环完整性的影响研究

发布时间：2018-01-05 14:26

本文关键词：储气库注采载荷对储层段水泥环完整性的影响研究　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：储气库是一种将已采出的天然气重新注入到地下废弃的油田或气田而形成的人工气藏,在天然气的供给和储备上起着十分重要的作用。水泥环是储气库注采井井筒完整性的重要屏障之一,其力学完整性的好坏严重影响注采井的生命周期与生产安全。研究注采载荷变化对水泥环完整性的影响,对提高储气库注采井水泥环的环空封隔能力,有效保证储气库注采井的井筒完整性具有非常重要的意义。本文建立套管-水泥环-井壁围岩的组合体模型,通过理论计算来判断水泥环的密封完整性。随后将不同循环应力环境下的水泥环作为实验研究对象,来探讨储气库注采载荷变化对水泥环密封完整性的影响规律。为了提高水泥环的承载能力,对水泥环进行力学性能改善,保证了水泥环的长期环空封隔能力。本文在理论研究与实验研究的基础上,形成了以下结论:(1)建立了考虑初始应力、井筒压力、地应力和温度作用下的水泥环密封完整性评价模型。利用理论评价模型,对X储气库水泥环进行了理论计算评价,评价结果发现现有水泥浆体系理论上可起到安全有效的密封作用。(2)对X储气库水泥环进行了密封完整性评价实验,实验结果表明现有水泥浆体系可进行较长时间的封固。进行了水泥环应力破坏实验,实验结果表明水泥环能够抵抗较高的压差。选取了不同注采压差对水泥环进行应力循环实验,压差越大,水泥环遭到破坏的风险越大。(3)通过选用不同的材料对水泥环基本力学性能进行了测试对比,选取了对水泥环的力学性能提升效果最好的碳纤维来改善水泥环力学性能。改性后的水泥环能够承受更长的循环加载周期和更大的内外压差,可为储气库的高效开发与安全生产提供有力的保障。
[Abstract]:Gas storage is a kind of artificial gas reservoir which is formed by re-infusing produced natural gas into underground abandoned oil or gas fields. Cement ring is one of the important barriers to the wellbore integrity of gas reservoir injection and production wells. Its mechanical integrity seriously affects the life cycle and production safety of injection-production wells. The influence of injection-production load change on the integrity of cement ring is studied to improve the sealing ability of cement-ring in gas reservoir injection-production wells. It is of great significance to ensure the wellbore integrity of gas reservoir injection-production wells effectively. In this paper, the combined body model of casing, cement ring and wall rock is established. The seal integrity of the cement ring is judged by theoretical calculation. Then the cement ring under different cyclic stress is taken as the experimental object. In order to improve the bearing capacity of cement ring, the mechanical properties of cement ring were improved. On the basis of theoretical and experimental studies, the following conclusion is reached: 1) the initial stress and wellbore pressure are considered. The evaluation model of cement ring seal integrity under the action of in-situ stress and temperature. Using the theoretical evaluation model, the theoretical evaluation of X gas storage cement ring was carried out. The evaluation results show that the existing cement slurry system can play a safe and effective sealing role in theory.) the seal integrity evaluation experiment of X gas storage cement ring is carried out. The experimental results show that the existing cement slurry system can be sealed for a long time, and the stress failure test of cement ring is carried out. The experimental results show that the cement ring can resist the higher pressure difference. The higher the risk of failure of cement ring is, the more basic mechanical properties of cement ring are tested and compared by selecting different materials. The carbon fiber which has the best effect on the mechanical properties of the cement ring is selected to improve the mechanical properties of the cement ring. The modified cement ring can withstand longer cycle loading cycle and greater pressure difference inside and outside. It can provide strong guarantee for high efficiency development and safe production of gas storage.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE82

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