本文關(guān)鍵詞： 高-過成熟頁巖 天然氣地球化學(xué) 頁巖氣成因 成因模式 頁巖氣賦存狀態(tài)　出處：《中國(guó)地質(zhì)大學(xué)(北京)》2017年博士論文　論文類型：學(xué)位論文

【摘要】：高-過成熟(Ro2.0%)是川渝鄂地區(qū)下古生界海相及南華北盆地下二疊統(tǒng)海陸過渡相富有機(jī)質(zhì)頁巖的重要特征之一。論文分析了川渝鄂地區(qū)下古生界海相和南華北盆地下二疊統(tǒng)海陸過渡相頁巖中天然氣的地球化學(xué)異常和頁巖氣成因,探討了下寒武統(tǒng)頁巖中氮?dú)鈦碓春透患瘷C(jī)理,建立了頁巖氣演化階段模型及高含氮頁巖氣成因模式,提出了頁巖氣來源及賦存狀態(tài)的同位素判識(shí)方法,主要取得了以下認(rèn)識(shí):(1)高-過成熟頁巖中天然氣地球化學(xué)特征往往出現(xiàn)煤型氣與油型氣難以區(qū)分的異�，F(xiàn)象。海相與海陸過渡相高-過成熟頁巖中天然氣地球化學(xué)的主要差異在于頁巖氣中的非烴組分,特別是體現(xiàn)在CO_2含量及其碳同位素組成的差異。海陸過渡相頁巖氣主要分布在CO_2含量大于5%且δ~(13)C(CO_2)值小于-10‰的范圍內(nèi),而海相頁巖氣則主要分布在CO_2含量小于5%且δ~(13)C(CO_2)值大于-15‰的范圍內(nèi)。(2)通過對(duì)秭地1井下寒武統(tǒng)和南華北盆地下二疊統(tǒng)頁巖氣中烷烴碳同位素倒轉(zhuǎn)的成因分析,認(rèn)為兩個(gè)地區(qū)頁巖氣同位素倒轉(zhuǎn)主要是頁巖氣在高-過成熟階段與水及含鐵金屬發(fā)生反應(yīng)引發(fā)的瑞利分餾所導(dǎo)致。四川盆地代表性的龍馬溪組頁巖氣鉆井?dāng)?shù)據(jù)表明,頁巖氣中甲烷、乙烷碳同位素倒轉(zhuǎn)程度與地層壓力系數(shù)及初始產(chǎn)氣量具有良好的正相關(guān)關(guān)系,對(duì)頁巖氣藏保存程度具有指示意義。(3)在分析了研究區(qū)頁巖氣地球化學(xué)特征的基礎(chǔ)上建立了頁巖氣演化階段模型。結(jié)合川渝鄂地區(qū)下寒武統(tǒng)頁巖氣地質(zhì)特點(diǎn)建立了三種高含氮頁巖氣成因模式,即有機(jī)質(zhì)熱解成因模式、大氣成因模式和復(fù)合成因模式,并對(duì)以上模式的主控因素進(jìn)行了分析,對(duì)下寒武統(tǒng)頁巖氣勘探具有指導(dǎo)意義。(4)建立了頁巖氣來源和賦存狀態(tài)的同位素判識(shí)方法,通過研究川渝鄂地區(qū)海相頁巖氣來源組成發(fā)現(xiàn),隨著頁巖成熟度的增加,頁巖氣中油裂解氣的比例降低。對(duì)南華北盆地海陸過渡相頁巖氣中游離氣和吸附氣含量進(jìn)行計(jì)算并對(duì)比測(cè)井解釋結(jié)果發(fā)現(xiàn),該方法計(jì)算結(jié)果與測(cè)井解釋結(jié)果具有良好的可對(duì)比性。論文系統(tǒng)研究了高-過成熟頁巖中天然氣地球化學(xué)成因及模式,延伸了頁巖氣地球化學(xué)的地質(zhì)應(yīng)用,對(duì)我國(guó)頁巖氣勘探實(shí)踐具有一定的參考意義。
[Abstract]:) is one of the important characteristics of the Lower Paleozoic marine facies in Sichuan, Chongqing and Hubei areas and the southern North China basin underground Permian transitional facies rich in organic matter shale. The paper analyses the Lower Paleozoic marine facies and the South North China Basin in Sichuan, Chongqing and Hubei regions. Geochemical anomalies of natural gas in the transitional facies shale of the Permian sea and land and the origin of the shale gas, The source and enrichment mechanism of nitrogen gas in Lower Cambrian shale are discussed. The evolution stage model of shale gas and the genetic model of high nitrogen content shale gas are established, and the isotopic identification method of source and occurrence state of shale gas is put forward. The main results are as follows: (1) the geochemical characteristics of natural gas in the overmature shale often occur abnormal phenomenon that it is difficult to distinguish the coal-type gas from the oil-type gas. The geochemistry of natural gas in the marine and oceanic transitional facies and the over-mature shale. The main difference in science lies in the non-hydrocarbon components of shale gas, In particular, the difference in CO_2 content and carbon isotopic composition shows that the marine and continental transitional shale gas mainly distributes in the range of CO_2 content greater than 5% and 未 ~ (13) C _ (13) C _ (C) _ (CO _ (2)) value less than -10 鈥，

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