前人對干燥裂紋（龜裂縫）的形成機(jī)理和擴(kuò)展規(guī)律進(jìn)行了大量的研究。然而,富有機(jī)質(zhì)頁巖中成巖微裂縫的形成機(jī)制尚不清楚。根據(jù)研究建議,對海相、過渡相和陸相頁巖樣品的微裂縫進(jìn)行了掃描電鏡研究。同時(shí),對頁巖中常見的泥質(zhì)礦物（蒙脫石、伊利石、高嶺石）進(jìn)行了實(shí)驗(yàn)研究,以確定干燥裂縫發(fā)育的主要控制因素,并探討這些因素對裂縫幾何形態(tài)的影響。頁巖中普遍發(fā)育的成巖收縮裂縫與干燥裂縫具有明顯的相似性。為模擬干燥裂縫的擴(kuò)展過程,闡明收縮裂縫的形成機(jī)理,論文采用了成巖裂縫模擬機(jī)和實(shí)驗(yàn)室烘箱等進(jìn)行了模擬試驗(yàn),結(jié)果表明,粘土含量、溫度和粘土層厚度是控制裂縫發(fā)生和發(fā)展的主要因素。裂縫寬度隨層厚增加而增大,隨著蒙脫石含量的增加而增大,但隨著高嶺石和伊利石含量的增加,裂縫寬度減小。對于某些單一成分的實(shí)驗(yàn)樣品來說,當(dāng)溫度達(dá)到100℃和230℃時(shí),干燥裂縫的數(shù)量將會進(jìn)一步增加。混合樣品則不存在這種現(xiàn)象。進(jìn)一步,92%的干燥裂縫均呈現(xiàn)為三臂型,臂間夾角為90-100度和170-180度。脫水過程中的含水量在裂縫形成過程中起著重要作用,可分為四個階段。大部分的裂縫都形成于初始和發(fā)展階段,此時(shí)主要形成初始的單一裂縫并開始分叉。在自然界... 

【文章來源】：中國地質(zhì)大學(xué)(北京)北京市 211工程院校 教育部直屬院校

【文章頁數(shù)】：155 頁

【學(xué)位級別】：碩士

【文章目錄】：
摘要
abstract
1 Preface
    1.1 Background and significance
        1.1.1 Background
        1.1.2 Significances
        1.1.3 Project supports
    1.2 Research status and existing problems
        1.2.1 Research status
        1.2.2 Existing problems
    1.3 Research content and technical ideas
        1.3.1 Research content
        1.3.2 Technical ideas
    1.4 Work completed
    1.5 Main achievements
2 The formation mechanism of diagenetic fractures of shale
    2.1 Characteristics and development patterns of desiccation cracks
        2.1.1 Basic characteristics of desiccation cracks
        2.1.2 Development patterns of desiccation cracks
        2.1.3 Geometrical parameters of desiccation cracks
    2.2 Formation mechanism of desiccation cracks
        2.2.1 Main mineral composition and characteristics of clays
        2.2.2 Mechanical condition for desiccation crack formation
        2.2.3 Stages of desiccation crack formation
        2.2.4 Main controlling factors of desiccation crack propagation
    2.3 Formation mechanism of shale diagenetic fractures and their distribution
        2.3.1 The model of formation processes from desiccation cracks to shale diagenetic cracks during diagenesis
        2.3.2 Analogy of formation mechanism and conditions of shale diagenetic fractures and clay desiccation fractures
        2.3.3.Formation mechanism of shale diagenetic fractures
3 Shale diagenesis
    3.1 Basic composition of shale
        3.1.1 Main mineral composition
        3.1.2 Organic matter composition of shale
        3.1.3 Fluids in shale
    3.2 Shale diagenesis
        3.2.1 Shale from marine facies
        3.2.2 Shale from transitional facies
        3.2.3 Shale from continental facies
    3.3 Main changes in shale diagenesis
        3.3.1 Under-compacted overpressure
        3.3.2 Cementation
        3.3.3 Mineral transformation
        3.3.4 Hydrocarbon generation
        3.3.5 Recrystallization
        3.3.6 Dehydration
4 Development mechanism of shale diagenetic fractures
    4.1 Main types of shale diagenetic fractures and their classification features
        4.1.1 Main types of shale diagenetic fractures
        4.1.2 Characteristics of shale diagenetic fractures
    4.2 Microfracture development mechanism
        4.2.1 Bedding cracks
        4.2.2 Stress tectonic cracks
        4.2.3 Shrinkage cracks
        4.2.4 Hydrocarbon generation cracks
        4.2.5 Undercompacted/ overpressure cracks
        4.2.6 Mineral transformation cracks
    4.3 Identification of main types of shale diagenetic fractures
    4.4 Microfracture combinations
5 Shale diagenetic crack diversity and main influencing factors
    5.1 Basic geological characteristics
        5.1.1 Sample diversity
        5.1.2 TOC contents of samples
    5.2 Differences of shale diagenetic fractures
        5.2.1 Shale from marine facies
        5.2.2 Shale from continental facies
        5.2.3 Shale from transitional facies
        5.2.4 Differences in diagenetic fractures of different types of shale
    5.3 Main influencing factors of shale diagenetic fracture formation
        5.3.1 Mineral composition
        5.3.2 Total organic carbon contents
        5.3.3 Maturity of organic matter
        5.3.4 Shale sedimentary facies
6 Conclusions
Gratitude
References
Plate1:SEM photos of microcracks in the shale from marine facies
Plate2:SEM photos of microcracks in the shale from continental facies
Plate3:SEM photos of microcracks in the shale from transitional facies
Appendix



本文編號：3519640