Character istics of Diagenetic Evolution of Chang 4 + 5 Sandstones ( Upper Triassic) in Yanchi-Jiyuan Area, Ordos Basin and Distribution of High-Quality Reservoir
-
摘要: 盐池—姬塬地区延长组长4+5砂岩由台型和坡型三角洲前缘砂体组成,以岩屑长石砂岩和长石砂岩为主,其中石英、长石和岩屑平均含量分别为24.7%、43.2%和10.0%,岩屑也以变质岩屑和火成岩屑为主,占岩屑总量的88.0%。砂岩目前处于早成岩阶段B期的晚期,Ro为0.8%,温度在70～90℃,主要受酸性成岩环境控制,因此次生溶孔发育。在对砂岩各种组分含量统计的基础上,定量计算表明机械压实作用是造成研究区原生孔隙消亡的最主要原因,其次为胶结作用,而由溶蚀作用增加的孔隙占初始孔隙度比例较小(﹤10%)。结合沉积相分析成果,在研究区可划分出3种沉积—成岩相带,即坡型三角洲前缘—绿泥石粘土膜胶结原生孔相、坡型三角洲前缘—晚期铁方解石胶结次生溶孔相和台型三角洲前缘—晚期铁方解石胶结相,其中有利的高孔高渗储层区主要分布在前两种有利沉积—成岩相带结合部位。Abstract: Chang 4 + 5 sandstones of Yanchang Formation in Yanchi-Jiyuan area are mainly composed of platform-type and slope-type delta front sandbodies. Lithic feldspathic and feldspathic sandstones are chief rock types, of which the average content of quartz, feldspar and rock fragments are 24.7%, 43.2% and 10. 0%, respectively, and meta-morphic and igneous fragments are dominant constitutes, accounting for 88. 0% of total fragment content. At present, these sandstones are in the late period of the Early diagenetic B stage (Ro = 0. 8% and T = 70290℃), so they are under the control of acidic diagenetic environment, being of abundant secondary dissolution porosity. On the basis of the statistics of sandstone compositions, it is indicated by the quantitative calculation that compaction is the dominant reason for the loss of the primary porosity in the study area, and next cementation, whereas the increasing ratio of porosity caused by the dissolution is relatively small ( < 10%). In combination with the results of sedimentary facies, three types of sedimentary-diagenetic facies zone could be divided, i. e. slope-type delta front-chlorite film primary porosity facies, slope-type delta front-late ferrous calcite cemented secondary porosity facies and platform delta front late ferrous calcite cemented facies, and the favorable reservoir facies ismainly distributed in the joint area of the former two facies zones.
-
Key words:
- diagenesis /
- sedimentary-diagenetic facies zone /
- high quality reservoir /
- Triassic series /
- Ordos basin /
-
[1] 1 付金华,罗安湘,喻建. 西峰油田成藏地质特征及勘探方向[J].石油学报,2004,(02):25-29.
2 喻建,韩永林,凌升阶. 鄂尔多斯盆地庆阳以南三叠系延长组油田成藏地质特征及油藏类型[J].中国石油勘探,2001,(04):13-19.
3 王琪,史基安,薛莲花. 碎屑储集岩成岩演化过程中流体-岩石相互作用特征[J].沉积学报,1999,(04):584-590.
4 Luo J L,Morad S,Zhang X L. Reconstruction of the diagenesis of the fluvial-lacustrine-deltaic sandstones and its influence on the reservoir quality evolution[J]. Science in China,Series D,2002,(07):616-625.
5 Houseknecht D W. Assessing the relative importance of compaction process and cementation to reduction of porosity in sandstones[J].AAPG BULLETIN,1987,(06):633-642.
6 Beard D C,Weyl P K. Influence of texture on porosity and permeability of unconsolidated sand[J].AAPG Bulletin,1973.349-369.
7 刘宝珺. 沉积岩石学[M].北京:地质出版社,1980.
8 钟广法,邬宁芬. 成岩岩相分析:一种全新的成岩非均质性研究方法[J].石油勘探与开发,1997,(05):62-66.
9 孙玉善,申银民,徐讯. 应用成岩岩相分析法评价和预测非均质性储层及其含油性-以塔里木盆地哈得逊地区为例[J].沉积学报,2002,(01):55-59.
10 Martin K R,Baker J C,Hamilton P J. Diagenesis and reservoir quality of Paleocene sandstones in the Kupe South Field,Taranaki Basin,New Zealand[J].AAPG Bulletin,1994,(04):624-643.
11 Dutton S P,Diggs T N. Evolution of porosity and permeability in the Lower Cretaceous Travis Peak Formation,East Texas[J].AAPG BULLETIN,1992,(02):252-269.
12 史基安,陈国俊,王琪. 塔里木盆地西部层序地层与沉积、成岩演化[M].北京:科学出版社,2001.
13 史基安,王金鹏,毛明陆. 鄂尔多斯盆地西峰油田三叠系延长组长6-8段储层砂岩成岩作用研究[J].沉积学报,2003,(03):373-379.
14 李凤杰,王多云,宋广寿. 陕甘宁盆地坳陷型湖盆缓坡带三角洲前缘短期基准面旋回与储层成因分析[J].沉积学报,2004,(01):73-78.
15 张金亮,司学强,梁杰. 陕甘宁盆地庆阳地区长8油层砂岩成岩作用及其对储层性质的影响[J].沉积学报,2004,(02):225-233. -
点击查看大图
计量
- 文章访问数: 489
- HTML全文浏览量: 9
- PDF下载量: 700
- 被引次数: 0
下载:
