龙马溪组页岩的力学特性及破坏模式研究

发布时间：2018-01-07 04:04

本文关键词：龙马溪组页岩的力学特性及破坏模式研究　出处：《地下空间与工程学报》2017年01期 　论文类型：期刊论文

【摘要】：井壁稳定性是页岩气勘探开发关键技术的核心问题之一。针对页岩井壁稳定问题,以四川盆地龙马溪组页岩为研究对象,结合实际钻井情况,开展了不同围压、加卸载模式、取芯角度、流体浸泡等一系列岩石力学实验,为页岩气的勘探和开发提供基础数据。研究表明:四川盆地龙马溪组页岩单轴抗压强度较高,脆性较强;卸载作用造成岩样破坏更加剧烈,破坏模式更加复杂;取芯方向与层理面夹角为15°时,岩样的抗压强度和内聚力最低,夹角为45°时,岩样的破坏最剧烈;流体浸泡使岩样的强度和内聚力大幅下降,岩样以剪切破坏为主,浸泡过油基钻井液的岩样的强度和内聚力损失最小;随浸泡时间的增长,岩样的内聚力和内摩擦角先快速降低后趋于平缓。
[Abstract]:Wellbore stability is one of the core problems in shale gas exploration and development. Aiming at shale wellbore stability, the shale of Longmaxi formation in Sichuan Basin is taken as the research object and different confining pressures are carried out in combination with the actual drilling conditions. A series of rock mechanics experiments, such as loading and unloading mode, core angle and fluid immersion, provide basic data for the exploration and development of shale gas. The study shows that the uniaxial compressive strength of shale in Longmaxi formation in Sichuan Basin is high. Brittleness is strong; The failure of rock samples is more severe and the failure mode is more complex due to unloading. When the angle between core direction and stratified plane is 15 掳, the compressive strength and cohesion of rock sample are the lowest, and when the angle is 45 掳, the damage of rock sample is the most severe. The strength and cohesion of rock samples are greatly decreased by fluid immersion, and the shear failure of rock samples is the main, and the loss of strength and cohesion of rock samples soaked with oil based drilling fluid is the least. With the increase of soaking time, the cohesion and friction angle of rock samples decrease rapidly and then tend to smooth.
【作者单位】：西南石油大学油气藏地质及开发国家重点实验室;
【基金】：国家自然科学基金面上项目(51274172);国家自然科学基金联合基金重点项目(U1262209)
【分类号】：TE21
【正文快照】： 0引言随着能源需求的增加和工业技术的进步,我国对天然气的需求量越来越大,我国天然气对外依存度呈逐年快速攀升趋势。页岩气作为非常规天然气资源,因其资源量巨大而备受社会关注[1]。页岩气储层钻井过程中,井壁坍塌失稳、钻井液漏失等井下事故频发,导致页岩水平井钻井周期长

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