长石砂岩中长石溶解作用发育机理及其影响因素分析
摘要: 松辽盆地和辽河盆地的砂岩储层中长石含量很高,次生孔隙主要是由长石颗粒溶解后形成的。本文运用扫描电镜、X衍射、氧碳稳定同位素等分析方法,对研究区砂岩储层中长石溶解作用发育状况以及溶解物质的迁移与沉淀的影响因素进行了分析,阐明了泥质岩在成岩过程中由于粘土矿物和有机质演化所释放出来的富含有机酸溶液对砂岩中长石溶解作用的发育产生着重要影响。
Annnalysis on Mechanism of Feldspar Dissolution and Its Influencing Factors in Feldspar-rich Sandstone Reservoir
- Lanzhou Institute of Geology, Chinese Academy of Sciences
Abstract: Porosity formed by the dissolution of unstable framework grains is one of the most important genetic types of secondary porosity,and feldspar is found to be the most extensive ones of the unstable framework grains. Songliao and Liaohe basins are two large petroliferous inland basins of Mesozoic and Cenozoic,in which has been constructed a clastic rock formation with great thickness.In sandstone there is above 20% unstable feldspar fragments,which is the requisite condition for the development of the secondary porosity. But it has been studied that the FGD of the grains, may not cause the increase of the reservoir permeability of the sandstone(Siebert,1984). The dissolution of a unit volume of feldspar may produce 0. 66 volume of Kaolinite and 0. 33 volume of quartz (Sullivan,1991).Therefore.only when the dissolved materials are transferred after dissolution the porosity of the sandstone can be effectively increased. This paper is based on analyzing the state of thermodynamics of feldspar dissolution process.The SEM,X一diffraction,oxygen and carbon stable isotopes, etc. analytical methods are adopted in research of the controlling factors of feldspar dissolution in Cretaceous sandstone in the region of Songliao basin and Palaeogene sandstone in the Liaohe basin. Through research,the author indicates that favors to development degree of feldspar dissolution are dependent on:(1)the organic and inorganic reaction time;(2)the characteristics and fluid condition of pore water;(3)the primary porosity of sandstone,and(4)the temperature and pressure,etc. These factors play different roles in different types of feldspar. The most important parameters are fluid condition,type and abundance of organic acid in fluid .which were closely related with the evolution of clay mineral and organic material in the diagenesis of mudstone.
史基安, 晋慧娟, 薛莲花. 长石砂岩中长石溶解作用发育机理及其影响因素分析[J]. 沉积学报, 1994, 12(3): 67-75.
引用本文: |
史基安, 晋慧娟, 薛莲花. 长石砂岩中长石溶解作用发育机理及其影响因素分析[J]. 沉积学报, 1994, 12(3): 67-75.
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Shi Ji'an, Jin Huijuan, Xue Lianhua. Annnalysis on Mechanism of Feldspar Dissolution and Its Influencing Factors in Feldspar-rich Sandstone Reservoir[J]. Acta Sedimentologica Sinica, 1994, 12(3): 67-75.
Citation: |
Shi Ji'an, Jin Huijuan, Xue Lianhua. Annnalysis on Mechanism of Feldspar Dissolution and Its Influencing Factors in Feldspar-rich Sandstone Reservoir[J]. Acta Sedimentologica Sinica, 1994, 12(3): 67-75.
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