【作者】 刘涛；

【导师】 黄思静；

【作者基本信息】 成都理工大学 ， 地质学， 2011， 硕士

【摘要】 本文选取鄂尔多斯盆地姬塬地区长8油层组储层砂岩中的自生高岭石作为研究对象,以中石油长庆油田勘探开发研究院与成都理工大学沉积地质研究院合作的科研项目《姬塬—华庆地区延长组第8油层组储层粘土矿物研究》为依托,通过对所选取样品的岩石学特征分析,结合岩石薄片的显微镜观察、扫描电镜、全岩X衍射定量分析等多种研究手段,探讨了姬塬地区长8油层组储层砂岩中自生高岭石的含量、赋存方式、分布规律等各种特征、形成机制以及它对储层发育的影响,取得了以下的一些相关认识:根据对岩石学特征和岩石薄片镜下的研究分析得出,岩屑长石砂岩和长石岩屑砂岩是研究区长8油层组储层砂岩的主要岩石类型,岩石骨架组分中34.71%的长石碎屑含量是一个显著的特征,岩石具有较低的成分成熟度和较高的结构成熟度,碳酸盐矿物是含量最多且分布最广的自生成岩矿物,自生高岭石在含量和分布规律上具有区域性。自生高岭石在砂岩中的平均含量为1.59%,主要分布在姬塬西部区域的长81小层中,其中自生高岭石的平均含量为2.60%;在赋存方式方面,自生高岭石常以充填在残余的原始粒间孔和长石溶孔等次生孔隙中的形式产出,伴随有自生高岭石晶间孔隙的形成。自生高岭石含量、赋存方式、分布规律等各种特征的特殊性是由它的形成机制造成的,由于姬塬西部区域更靠近长7烃源岩沉积中心附近,有机酸的向下运动对临近长8油层组储层砂岩的侵蚀造成了自生高岭石含量和分布在研究区中区域性的差异;有机酸对岩石中长石等不稳定硅酸盐矿物的溶解,是自生高岭石沉淀的主要成因。在孔隙构成方面,以残余粒间孔为主的原生孔隙是储集空间的主要部分,次生孔隙（主要为长石溶孔、岩屑溶孔、晶间孔隙以及粒间溶孔等）也占有着较多的储集空间,其中,姬塬西部长81小层中的次生孔隙和长82小层中的原生孔隙相对于其他区域含量较多;在物性特征方面,储层砂岩的孔隙度平均值为7.29%,渗透率平均值为0.38×10^-3μm²,得出姬塬地区长8油层组砂岩储层属于低孔隙度特低渗透率致密型储层。自生高岭石一方面在沉淀过程中占据了储集空间,另一方面,自生高岭石晶间孔隙可以扩大部分储集空间,因此需要定量地研究它对储层发育的影响。它对原生孔隙的发育有不利的影响,两者的相关系数为-0.27,但有利于次生孔隙的发育,相关系数为+0.2,总体上自生高岭石对储层孔隙的发育上是保持性的作用;在储层物性方面的影响上,作用不很明显,自生高岭石造成孔隙度和渗透率的降低程度是很有限的。更多还原

【Abstract】 Based on the scientific research task of“The research on Clay minerals of Chang 8 oil-bearing Formation in Jiyuan-Huaqing area”,and by analyzing the characteristics of rock in chang 8 oil-bearing formation sandstone of Jiyuan area,combining the optical microscopy、XRD、SEM analyses on core samples and other research methods. This thesis mainly discusses the characteristics of authigenic kaolinite,such as its content、occurrence、distribution、formation and the influence of authigenic kaolinite on the reserivor development in chang 8 oil-bearing formation sandstone of Jiyuan area. this thesis gives some conclusions in the following:Based on the description of well cores,the identification of the thin section and the grain size analysis,it shows that the reservoir rock type are dominantly the lithic arkose and feldspathic lithic sandstone in Jiyuan area,34.71% of the average content of feldspar is a significant feature in the rock matrix,which is characterized by low composition maturity and high textural maturity. Carbonate is the most major authigenic minerals in the study area,the authigenic chlorite and authigenic kaolinite only can be found in some area .The average content of authigenic kaolinite is 1.59% in chang 8 oil-bearing formation sandstone of Jiyuan area,it mainly distributes in chang-81 sub-oil-bearing formation of the western region in the study area,in which its average content is 2.60%;Authigenic kaolinite often occurs in the original intergranular pore and secondary porosity（such as feldspar dissolution porosity）,at the same time,intergranular pore of authigenic kaolinite appears.The particularity of the various features of authigenic kaolinite is caused by its formation mechanism.Because the western of Jiyuan area is closer to the centre of hydrocarbon source rocks of chang 7 oil bearing formation,then the downward movement of organic acids causes the dissolution of many feldspars and the precipitation of authigenic kaolinite,moreover,it also causes all the kinds of characteristics of authigenic kaolinite.In the composition of pore of chang 8 oil-bearing formation sandstone in Jiyuan area,the original intergranular pore is the main part of the reservoir space,secondary porosity（feldspar dissolution porosity,debris dissolved pore and intergranular dissolution pores,etc）also accounts for part of the reservoir space. On the other hand,it also finds that the secondary porosity in chang-81 sub-oil-bearing formation of the western region in the study area is more than other area,and the content of the original pore in chang-82 sub-oil-bearing formation of the western region is the most one;Research in reservoir properties,the average porosity of sandstone is 11.66% and the average permeability is 0.38×10^-3μm²,in which we can see that it is ultra-low porosity and low permeability reservoir in chang 8 oil-bearing formation sandstone of Jiyuan area.On one hand,authigenic kaolinite occupies the reservoir space in its formation process. On the other hand,intergranular pore of authigenic kaolinite can expand part of the reservoir space. Therefore,quantitative research required in the study of authigenic kaolinite,it is harm to the development of primary porosity,and their correlation coefficient is -0.27,at the same time,authigenic kaolinite conducives to the development of secondary porosity,the correlation coefficient is +0.2. All in all,authigenic kaolinite takes the retention diagenesis in the the development of pore of the study area;Authigenic kaolinite in the study area on the impact of reservoir properties is not obvious,the decrease of porosity and permeability caused by authigenic kaolinite is very limited.更多还原