【作者】 陈要辉；

【导师】 闫铁；

【作者基本信息】 大庆石油学院 ， 油气井工程， 2008， 博士

【摘要】 海拉尔油田凝灰质储层蕴藏着极为丰富的石油资源,是“十一五”期间重要的勘探开发区块之一。海拉尔油田凝灰质储层属于典型的低孔低渗储层,自然产能很低,储层结构和岩性复杂,常规砂岩的增产技术呈现出很强的不适应性,水力压裂施工频繁出现砂堵事故,导致不能达到预期的加砂量,甚至施工失败,极大的影响了储层的开发效果。基于上述状况,本文开展了海拉尔油田凝灰质储层岩石水力压裂力学理论研究,研究内容与成果如下:首先,系统的描述了海拉尔油田凝灰质储层的岩性、电性和沉积等特征;通过薄片鉴定、X-射线衍射、X-衍射全岩分析、电子探针分析、扫描电镜、电镜能谱分析和岩石物性分析等试验,对凝灰质储层矿物学特征进行了分析;通过水浸实验研究了凝灰质储层岩石的水理特征;应用波速各向异性测试、粘滞剩磁法、井筒崩落及热弹性应变恢复确定了储层地应力的方向,通过差应变法、现场小型压裂施工得到储层地应力的大小。分析表明,凝灰质储层岩性复杂,粘土矿物含量高,非偏碱性含凝灰质储层遇水稳定,不会分散,属于正常的硬地层,而易水化碱性和偏碱性含凝灰质储层,遇水水化后将发生软化或泥化作用,对水力压裂产生不利的影响。其次,通过密度测定、抗张强度试验、单轴压缩试验、三轴压缩试验,获取了海拉尔油田凝灰质储层的岩石力学参数。从凝灰质岩石材料内部所含缺陷分布的随机性出发,将连续损伤机理和统计强度理论有机的结合起来,建立了海拉尔油田凝灰质岩石损伤软化的本构模型。第三,考虑原岩应力、井筒内压及压裂液渗滤影响,推导了井筒应力场,建立了海拉尔油田凝灰质储层裸眼完井及射孔完井的破裂压力计算模型;根据缝尖应力分布,应用断裂力学理论,建立了I-II型复合受载裂缝的最大应力强度准则。应用有限元软件对模型进行了验证。第四,根据裂缝宽度模型、压裂液流动压降模型、高度延伸模型及连续性方程,应用迭代法对海拉尔油田凝灰质储层裂缝几何形态进行了计算。本文将断裂力学、损伤力学理论与海拉尔油田凝灰质储层性质紧密联系起来,通过理论推导与实验分析,系统的研究了海拉尔油田凝灰质储层的水力压裂力学理论。通过本文的研究,为海拉尔油田凝灰质储层的有效开发提供了强有力的理论指导与技术支持,具有重要的学术价值与现实意义。更多还原

【Abstract】 Tuffaceous formation in Hailaer basen, which is one of the most important exploration and development tracts during the Eleventh Five-Year Plan period, storages rich petroleum resources. Its low-porosity and low-permeability induce poor natural productivity. In addition, its structures and lithological characters are very complex which make the conventional stimulation technologies unsuitable in the situation. Furthermore, sand plug occures frequently during the hydraulic fracturing operations, which could lead to poor proppant concentration and even operation failure. According to these conditions, a series of studies are proceeded and valuable results are achieved in this paper.Firstly, the lithological, electrical and sedimentary characters of the formation are described systematically in the paper. The mineralogical characters of the tuffaceous formation are analyzed by means of slice identification, X ray diffraction, SEM and so on. The enhydrous character is studied by waterlogging test. The orientation and value of formation stress are acquired by anisotropic wave velocity test, viscous remanence method, borehole caving, ASR test, differential strain method and mini-frac test. Based on the analysis, it is shown that the lithological characters of the formation are very complicated and the clay mineral content is high. The alkaline formation is sensitive to the water which induces soften and dispersion of formatin rock and it is adverse for hydraulic fracturing operation, but the others are stable to the water.Secondly, the mechanics parameters of tuffaceous formation rock are acquired by density measurement test, Brazilian test, uniaxial compression test and triaxial compression test. Based on the distributing randomicity of the defects inside the tuffaceous rock, CDM and statistical intensify theory, the constitutive equation is established in the paper.Thirdly, considering the influence of in situ stress, fluid pressure and infiltration of fracturing fluid, the borehole stress field model is deduced and the breakdown pressure calculating model for open-hole completion and conventional completion are established. The maximal intensify criteria of I-II mode fracture propagation is established based on the stress distribution and fracture mechanics. The model is testified by finite element software.Fourthly, the fracture width model, fluid flow model, fracture height propgating model and continuum model are established in the paper. The fracture geometric parameters can be calculated by iterative method.This paper combines the fracture mechanics, damage mechanics with tuffaceous formation characters; accomplishes the experimental analysis and academic study; and researches systematically the hydraulic fractur ing mechanics theory. Based on aboved work, the powerful theoretical instructions and technical support can be supplied for effective development of tuffaceous formation in Hailaer oilfield. Moreover, it has important academic value and realistic meaning.更多还原