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最終更新日:2016年9月10日
起源物質 |
ケロジェン起源説 |
図K2 ケロジェンおよび石炭マセラルのタイプ: タイプI〜IIIケロジェンが示されている。縦軸が水素/炭素比(H/C),横軸が酸素/炭素比(O/C)で,van Krevelen図という。H/C,O/Cが高いほど熟成度が低い。石炭の場合は、その端成分の種類で判別されている。水生藻類由来のalginite,植物の表皮や胞子などから形成されるexinite,木質のvitriniteで表現されている(Vandenbroucke and Largeau, 2007引用)。 北大・理・生物地球化学研究室(HP/2011/5)による『生物・高分子地球化学トピックス』による |
Monash University(HP/2011/5)の中のBeardsmore & Cull(2001)による『Crustal Heat Flow: A Guide to Measurement and Modelling』の『Chapter 5: Thermal Maturity』から |
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non reagent nisi soluti(HP/2011/5)による『Evolusi termal material organik (2)』から |
Evolution of kerogen. A modified Van Krevelen diagram shows changes to kerogen brought on by increased heat during burial. The general trend in the thermal transformation of kerogen to hydrocarbon is characterized by the generation of nonhydrocarbon gases, and then progresses to oil, wet gas, and dry gas. Type IV is residual kerogen considered to be primarily dead carbon or inertinite that does not generate hydrocarbon. |
The naturally occurring, solid, insoluble organic matter that occurs in source rocks and can yield oil upon heating. Kerogen is the portion of naturally occurring organic matter that is nonextractable using organic solvents. Typical organic constituents of kerogen are algae and woody plant material. Kerogens have a high molecular weight relative to bitumen, or soluble organic matter. Bitumen forms from kerogen during petroleum generation. Kerogens are described as Type I, consisting of mainly algal and amorphous (but presumably algal) kerogen and highly likely to generate oil; Type II, mixed terrestrial and marine source material that can generate waxy oil; and Type III, woody terrestrial source material that typically generates gas. |
Schlumberger(HP/2011/5)による『Oilfield Glossary』の中の『Kerogen』から ※縦軸はH/C原子比で、横軸はO/C原子比。タイプTがケロジェンから典型的な石油への変化経路。 |
Figure 5.29 Classification scheme for kerogen types based on the hydrogen index and oxygen index (after Cornford, 1998). Inset diagram shows the original classification of kerogen on the basis of H/C and O/C atomic ratios (after Tissot and Welte, 1984). Robb(2006)による『Introduction to Ore-Forming Processes』から |
a, Van Krevelen diagram showing the chemical evolution of immature kerogen of varying composition (type I, II, III and IV) at increasing levels of thermal maturity (based on ref. 2). Levels of thermal maturity are indicated by isochors of vitrinite reflectance (%R0), a widely used geochemical indicator that integrates the effects of time and temperature during thermal maturation of sediments. In general, kerogen composition moves from the upper right regions of the figure to the lower left with increasing maturity. b, Traditional model of the amount and timing of organic alteration products generated during progressive burial in sedimentary basins that assumes oxygen and hydrogen in organic alteration products are derived only from kerogen (modified from ref. 2). The form of this figure is constrained by the maturation trends shown in the Van Krevelen diagram. c, Schematic illustration of the amount and timing of organic alteration products generated if water and minerals are allowed to contribute the requisite hydrogen and oxygen for the formation of hydrocarbons and oxygenated compounds such as carbon dioxide and carboxylic acids. Ultimately, production of oxygenated products and methane will cease owing to exhaustion of a reactive carbon source. The depth at which this occurs is unknown. Seewald(2003)による『Organic-inorganic interactions in petroleum-producing sedimentary basins』から |
図1 石油の成り立ち |
Cross-section of a generic petroleum system, including source and reservoir rocks, traps, and migration pathways. (modified from Magoon, 1988) 〔Lowell E. Waitee氏によるWelcome to Geocomplexity.comの『Earth Systems』の中の『Petroleum systems』から〕 |
生成温度 |
石油技術協会(HP/2011/5)による『石油・天然ガスの根源と鉱床』から |
石油の生成温度−堆積盆地の昇温速度と“有機物熟成”− 石油の生成温度: タイプ II ケロジェンの例
反応速度が長いほど, 低温でも生成可能 ケロジェンタイプと石油生成温度 同じ熱史を経験してもケロジェンタイプによって石油生成温度、生成量が異なる。 ケロジェンの種類による生成温度の違い
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鈴木(2003)による『石油はあと何年利用できるか ?: 1. 石油とは ?』から |
生成時代 |
Several studies have found that rich oil source rocks are unevenly distributed through the past 500 million years of geologic timescale with the mid-Cretaceous pulse as the “king of world oil.” Note that these data are for conventional crude (not for unconventional hydrocarbons) and for deposition ages of source rocks (not ages of oil generation). Illustration: Rasoul Sorkhabi |
Various changes in the Earth's oceans and atmosphere during the mid-Cretaceous probably brought about by a superplume upwelling. Compiled from Larson (Geology, October 1991) and several other sources. |
Sourkhabi(HP/2011/10)による『Mid Cretaceous Source Rock Enigma』から |
図 地質時代別にみた巨大油田の埋蔵量 自然の摂理から環境を考える(HP/2011/5)の中の『プレートテクトニクス(その2)石油の起源』(2007/9)から |
石油の地質時代 |
石油の生成された年代
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鈴木(2003)による『石油はあと何年利用できるか ?: 1. 石油とは ?』から |
トラップ |
図2 石油トラップの種類(物理探査学会編「図解物理探査」より引用。ピンク色はガス層、黒色は油層、水色は水層をそれぞれ示す。 松島(2007)による『「石油ピーク」論を理解するための基礎知識(1)−石油資源−』から |
Figure 5.33 Geological scenarios for hydrocarbon trap sites. (a) Stratigraphic traps represented by unconformities, pinch-outs, and carbonate “pinnacle” reefs. (b) Structural traps represented by faults, diapiric features, and anticlinal or dome like structures. (c) Other features, such as hydrodynamic and asphalt traps (after Hunt, 1979; Bjorlykke, 1989). Robb(2006)による『Introduction to Ore-Forming Processes』から |