四川盆地三叠系嘉陵江组—雷口坡组天然气成藏
领字开头的成语差异性研究
摘要
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为深入探讨四川盆地嘉陵江组—雷口坡组气藏成藏的差异性及总结其天然气的成藏规律，笔者收集大量前人资料，并分不同构造单元分析天然气的基本成藏地质条件，包括烃源、储层、封盖、圈闭、运聚、保存等方面，揭示不同构造单元间天然气成藏的差异性，包括气源差异性、沉积差异性、储层差异性、成藏过程的差异性，最终总结了四川盆地嘉陵江组和雷口坡组天然气的成藏规律。
据天然气组分和碳同位素分析，认为四川盆地嘉陵江组气藏的气源以外源为主，且除了川中地区嘉陵江组气藏天然气中没有上二叠统煤系烃源岩所贡献的煤型气外，盆地内大部分地区嘉陵江组气藏中的天然气为煤型气（二叠系）与油型气（二叠系、志留系）的混合。对四川盆地嘉陵江组各期的沉积相进行了研究，在嘉陵江组沉积时期，海水的进退共发生了三次，其沉积呈现出台地总体上不断局限化的特点。相应地，四川盆地中部以及东部地区能够划分出三种不同的沉积相带，分别是局限台地、蒸发台地以及开阔海台地；而四川盆地南部地区仅发育半局限—局限台地和开阔海台地。通过岩心、薄片观察，认为四川盆地嘉陵江组储集岩以灰岩和白云岩为主，常见的储集空间类型有粒间孔、粒内孔、晶间孔、溶解孔、缝洞、构造缝等。四川盆地嘉陵江组储层的物性总体上表现出低孔和低渗的特征：川东地区以Ⅲ类
储层为主，孔渗相关性较强；川中孔隙度较低，孔渗相关性差；川南地区孔隙度较差、渗透率较好，裂隙较为发育。
通过对四川盆地嘉陵江组典型构造天然气成藏过程的差异性研究，认为二叠系的高—过熟油裂解气在川东和川南地区主要是依靠烃源断层向上覆岩层运移，而川中地区则是通过高压破裂缝向上运移；天然气在区域性石膏盖层的封盖作用下，聚集在嘉陵江组碳酸盐岩储层中；圈闭类型主要为岩性圈闭、构造圈闭或它们的组合。嘉陵江组气藏的形成大致包含了古油藏的演化、古气藏的演化以及现今气藏的调整等过程，其中古油藏赋存的层位、形成与破坏的时间在盆地内不同构造单元上具有差异性：第一，川东和川南地区存在嘉陵江组古油藏，而川中地区发育二叠系或飞仙关组古油藏；第二，川东地区的古油藏在印支运动之后的早侏罗世形成，而川中和川南地区的古油藏在三叠纪印支运动之前形成。四川盆地嘉陵江组天然气成藏规律可概括为：“高压驱动，断层裂缝疏导，流体跨层流动，膏盖油裂解气成藏”。
通过常规有机地球化学及充填物锶、碳、氧稳定同位素地球化学特征等方法研究四川盆地雷口坡组天然气的气源，认为雷口坡组气藏都为混源，顶部雷口坡
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组四段风化壳气藏气源主要来自于上覆上三叠统泥质烃源岩，二次运移通道为雷口坡组风化壳。雷口
北京植物园>说开头的成语坡组三段、一段滩相储层气藏其气源主要来自下伏二叠系烃源岩，运移通道为通源断层或裂缝。
通过典型井的研究对比发现四川盆地雷口坡组气藏储层有两种，一为主要受沉积相控制的内幕滩相颗粒碳酸盐岩储层，其最为发育的储集空间类型为原生粒间孔、鸟眼孔、晶间孔和生物体腔孔等；二为受雷口坡顶面岩溶体系控制的风化壳岩溶储层，储集空间类型为白云石晶间（溶）孔和溶蚀孔缝。
四川盆地雷口坡组气藏圈闭类型可以分为两个不同的类别，一是主要受构造控制的内幕构造型气藏，二为主要受地层（岩性）控制的构造－地层型气藏。四川盆地雷口坡组气藏直接盖层也可分为二类，一是雷口坡组顶部岩溶气藏其上的上三叠统泥岩盖层，二是雷口坡组内幕气藏其内幕膏岩盖层。
四川盆地雷口坡组可分为两大类气藏。一为气源主要来自上覆烃源不含硫化氢的岩溶型构造—地层气藏；二为气源主要来自下伏烃源岩含硫化氢内幕滩相储层构造气藏。四川盆地雷口坡组天然气成藏规律概括为“源分上下，运移上壳下断；储分两种，顶溶内滩；圈闭两分，内顶有别；封盖顶泥内膏，藏成两类”。
关键词：四川盆地嘉陵江组雷口坡组天然气成藏差异性天然气成藏规律
书英语II
The Differences Study of Natural Gas Accumulation of Triassic Jia-lingjiang and Lei-koupo Formatio
n in Sichuan Basin
Abstract
For studying the differences of natural gas accumulation of Triassic Jia-lingjiang and Lei-koupo formation in Sichuan Basin, and summarizing the regularity of natural gas’ accumulation, the author collected a large number of predecessors' information, studying the different tectonic units’ basic geological conditions of hydrocarbon accumulation, including hydrocarbon source condition, rervoir condition, aling system conditions, conditions, trap conditions and prervation conditions; carefully summarized gas accumulation differences between different tectonic units, including gas source diversity, rervoirs’ difference, dimentary difference, the process of hydrocarbon accumulation diversity, finally summarized the regularity of natural gas accumulation of Triassic Jia-lingjiang and Lei-koupo formation in Sichuan Basin.
With the carbon isotope and gas component analysis, to think that the gas source of Jia-lingjiang formations’ gas rervoir is complex, is given priority to with exogenous, most areas of the basin is Permian coal type gas or the Permian and Silurian oil type gas hybrid, except the middle of Sichuan basin, the lack of early Permian coal type gas.
佩帏
Through the study of dimentary facies of Jia-lingjiang formation’s every dimentary times in Sichuan basin, to think that in three times during a advance and retreat, the dimentary characteristics of Jia-lingjiang formation is salization to localization to salinization of platform. It can be divided into three pha belt in middle and east of Sichuan basin: a platform , limited a platform and evaporative platform. It only develops open a platform mi-limited—limited a platform pha in south of Sichuan basin. Through the cores’ and rock slices’ study, to think that Jia-lingjiang formations’ rervoir rock is mainly constituted by limestone and dolomite, familiar types of rervoir space consists of intergranular pore and intragranular pore, dissolved pore, hole, structural fractures, etc. Rervoirs’ physical property is characterized by low porosity and low permeability. In the east of Sichuan region is
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given priority to with type rervoir, porosity and permeability strong correlation; In the middle of Sichuan region, low porosity, porosity and permeability poor correlation; In the south of Sichuan region, rervoir is generally characterized by low porosity and high permeability, good at cracks’ development.
Through the differences study of natural gas accumulation process of typical structures in the east and middle and south of Sichuan basin, to think that Permian’s high—over maturity oil splitting gas go to the upper rocks mainly rely on hydrocarbon source faults(east and south of Sichuan basin) or high pressure broken crack(middle of Sichuan basin), under the aling gland condition of regional plaster covering strata, it
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gathered in carbonate rervoir of Jia-lingjiang formation. The type of trap is lithology trap or structure trap or their combination. The gas pools’ of Jia-lingjiang formation today experienced ancient oil pool→ancient gas pool→prent gas pool. The ancient oil pool’s formation and occurrence time have differences in the basin: First, the middle of Sichuan basin produce Permian’s and Fei-xianguan formation’s ancient oil pools, and the east and south of Sichuan basin produce Jia-lingjiang formation’s ancient oil pools. Secondly, The ancient oil pools of middle and south area formed before the Indosinian Movement, but the ancient oil pools of east area formed at early Jurassic when the Indosinian Movement is over. The natural gas accumulation of Jia-lingjiang formation in Sichuan Basin follow the regularitys: “high pressure driving, fluid flow across formation, fault and fracture dredging, plaster covering and decomposition gas accumulation”.
Through general geochemical method and strontium, carbon and oxygen stable isotopic characteristics method rearching the gas source of Lei-koupo formation in Sichuan basin, to think that the gas source of Lei-koupo formation gas rervoir is mixing source, the gas source of T2l4 weathering crust gas rervoir which on the top of Lei-koupo formation mainly from the upper Triassic mudstone hydrocarbon source rocks and condary migration channel mainly is weathering crust; the gas source of T2l3 and T2l1 beach facies rervoir gas rervoir is mainly from Permian hydrocarbon source rocks, the migration pathway is connecting hydrocarbon source fault or cracks.
Through contrasting typical wells’ rervoir characteristics, the rervoir of Lei-koupo formation have two types: The first is beach facies carbonate rervoir which is mainly controlled by the dimentary facies, the most developed rervoir space types include primary intergranular pore, birds eye pore, biological body cavity pore and intragranular pore, etc. The cond is weathering crust karst rervoir which is controlled by the karst system on the top of Lei-koupo formation, rervoir space types is dolomite intercrystal(dissolved) pore and dissolution pore or am.
The trap types of Lei-koupo formation gas rervoir can be divided into two different categories, one of them is mainly controlled by tectonic insider structural trap gas rervoir; another is mainly controlled by the strata (lithology) tectonic - formation gas rervoir. The direct caprock of Lei-koupo
formation gas rervoir also can be divided into two categories, one of them is Upper Triassic mudstone cap rock which upon the karst rervoir that on the top of Lei-koupo formation; another is the gypsum rock inside the insider gas rervoir of Lei-koupo formation.9月30
充足的英文The gas rervoirs’ type of Lei-koupo formation can be divided into two categories, the one is karst type structure - formation gas rervoir who gas source is mainly from overlying hydrocarbon source that does not containing the hydrogen sulfide, the cond is inside beach facies rervoir gas rervoir of construction who gas source is mainly from the underlying source rock containing hydrogen sulfide. The natural gas accumulation of Jia-lingjiang formation in Sichuan Basin follow the
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regularitys: “gas source from upside or downside, upper gas migration through weathering crust, lower gas migration through faults; rervoir is divided into two kinds, upper is weathering crust karst rervoir and internal is beach facies carbonate rervoir; the trap have two types, there are differences between the top and the insider; upper rervoir blocked by mudstone, internal rervoir blocked by gypsum rock, gas rervoir is divided into two types.”
Keywords: Sichuan basin, Jia-lingjiang formation, Lei-koupo formation, Differences of natural gas accumulation, Regularities of natural gas accumulation
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