本文關(guān)鍵詞： 有機(jī)質(zhì) 孔隙結(jié)構(gòu) 熱演化 排烴 延長(zhǎng)組　出處：《中國(guó)科學(xué)院廣州地球化學(xué)研究所》2017年博士論文　論文類型：學(xué)位論文

【摘要】：泥頁(yè)巖的孔隙度和孔隙結(jié)構(gòu)對(duì)頁(yè)巖油氣的儲(chǔ)集和運(yùn)移具有重要的意義。熱演化過程中有機(jī)質(zhì)賦存狀態(tài)的變化對(duì)孔隙發(fā)育影響顯著,但不同熱演化階段的主控因素與相應(yīng)的機(jī)制有待深入研究。本文以鄂爾多斯盆地東南部延長(zhǎng)組頁(yè)巖為主要研究對(duì)象,綜合利用低壓N2/CO2吸附、He密度法、高壓壓汞和場(chǎng)發(fā)射掃描電子顯微鏡(FE-SEM)等多種方法,分析了地質(zhì)樣品和熱模擬實(shí)驗(yàn)樣品的孔隙結(jié)構(gòu)和體積的變化規(guī)律,力圖闡明富有機(jī)質(zhì)頁(yè)巖熱演化過程與孔隙發(fā)育的關(guān)系。本次工作主要認(rèn)識(shí)如下:(1)鄂爾多斯盆地東南部的延長(zhǎng)組長(zhǎng)7、長(zhǎng)9段泥頁(yè)巖的有機(jī)質(zhì)類型主要為Ⅱ型,長(zhǎng)7段樣品的成熟度主體在生油初期和高峰期,而長(zhǎng)9段樣品的成熟度主體在生油后期和凝析油階段。抽提后頁(yè)巖甲烷吸附量明顯高于干酪根,并且全巖甲烷吸附量與粘土礦物含量之間具有明顯的正相關(guān)關(guān)系,表明干燥后泥頁(yè)巖的甲烷吸附量受粘土礦物含量影響較大。(2)FE-SEM觀察結(jié)果表明,延長(zhǎng)組頁(yè)巖中的有機(jī)質(zhì)孔隙按發(fā)育程度分為不發(fā)育、發(fā)育差、發(fā)育良好與高度發(fā)育四種。孔隙不發(fā)育的有機(jī)質(zhì)包括高等植物來(lái)源有機(jī)質(zhì)、固體瀝青、層狀有機(jī)質(zhì);孔隙主要發(fā)育在充填在礦物顆粒之間的小塊固體瀝青中;孔隙高度發(fā)育的有機(jī)質(zhì)具有納米級(jí)纖維狀結(jié)構(gòu),與胞外聚合物這類生物結(jié)構(gòu)類似。(3)TOC大于5%的泥頁(yè)巖孔隙發(fā)育差,主要原因有兩個(gè):其一,有機(jī)質(zhì)含量高的泥頁(yè)巖中殘留瀝青量也高,瀝青運(yùn)移到礦物顆粒之間的孔隙導(dǎo)致孔隙體積減小,抽提后泥頁(yè)巖的孔隙體積明顯高于抽提前樣品,證明殘留瀝青占據(jù)了處于生油窗泥頁(yè)巖的孔隙;其二,耐壓實(shí)的礦物顆粒支撐作用減小,導(dǎo)致頁(yè)巖壓實(shí)程度高,從而制約了孔隙發(fā)育。(4)高壓半封閉體系和封閉玻璃管體系熱模擬實(shí)驗(yàn)結(jié)果的對(duì)比分析表明,高壓半封閉體系中對(duì)巖石顆粒的壓實(shí)抑制了有機(jī)質(zhì)裂解,進(jìn)而導(dǎo)致了相對(duì)封閉玻璃管體系明顯偏高的排烴強(qiáng)度。在生油階段,高壓半封閉體系和封閉玻璃管體系的孔隙體積明顯降低,抽提前-后樣品N2吸附量的對(duì)比表明油充填是導(dǎo)致孔體積降低的主要原因,在生油高峰期孔隙開始發(fā)育;油裂解階段是孔隙發(fā)育最主要的時(shí)期,高壓半封閉體系中的油裂解產(chǎn)生的高流體壓力導(dǎo)致了高溫階段的強(qiáng)烈排烴,樣品的中-大孔的體積有明顯增長(zhǎng)且其增長(zhǎng)幅度明顯高于相同熱演化階段中封閉玻璃管體系獲得的樣品,而兩個(gè)體系的微孔體積增長(zhǎng)趨勢(shì)和大小相似。(5)有機(jī)質(zhì)類型和有機(jī)質(zhì)含量不同的富有機(jī)質(zhì)泥頁(yè)巖的模擬實(shí)驗(yàn)結(jié)果對(duì)比顯示:有機(jī)質(zhì)類型越好,TOC含量越高的泥頁(yè)巖,其排烴效率越高、孔隙體積增長(zhǎng)越多。與Ⅱ/Ⅲ型泥頁(yè)巖相比,容易生油的有機(jī)質(zhì)類型為Ⅰ、Ⅱ型的泥頁(yè)巖樣品在熱解過程中更容易產(chǎn)生大孔。壓實(shí)作用對(duì)大孔體積較高的樣品的孔隙體積增長(zhǎng)有明顯的抑制作用。
[Abstract]:The porosity and pore structure of shale play an important role in the reservoir and migration of shale oil and gas. However, the main controlling factors and the corresponding mechanism of different thermal evolution stages need to be deeply studied. In this paper, the shale of Yanchang formation in the southeast of Ordos Basin is taken as the main research object, and the density method of he adsorption with low pressure N _ 2 / CO _ 2 is used synthetically. Various methods, such as high pressure mercury injection and field emission scanning electron microscope (FE-SEM), are used to analyze the variation of pore structure and volume of geological and thermal simulated samples. This paper tries to elucidate the relationship between the thermal evolution process of organic shale and pore development. The main understanding of this work is as follows: 1) the Yanchang formation in the southeast of Ordos Basin is 7, and the organic matter type of shale in Chang 9 is mainly type 鈪，

本文編號(hào)：1551046