Abstract : yanchang series is a typical low permeability reservoir , and its favourable sandstone reservoir is delta facies . heavy compaction , cementation and heterogeneity exist in it . according to the analysis of the main control factors of forming the secondary pore , it is held that the secondary pore in longdong area is controlled by both favorable facies belt and abnormal formation pressure . it is also held that the formation of the abnormal formation pressure is due to the dewatering of the clay mineral during diagenesis because the dewatering time is identical with the decarboxylation time of organism . organic acid and co2 are driven to adjacent favorable reservoirs under the abnormal formation pressure , and a lot of secondary pore is produced in the runners . from the present exploration result , it is useful to predicting the development of secondary pore to study the distribution of abnormal formation pressure 文摘:陕甘宁盆地三叠系延长统是国内外典型的低渗特低渗油田，储集层主要为三角洲砂体，压实作用和胶结作用强烈，储层非均质性非常严重，因此预测次生孔隙发育带是寻找油气聚集带的关键.通过对陕甘宁盆地陇东地区延长统次生孔隙形成的主控因素分析，认为陕甘宁盆地延长统次生孔隙的形成除了受沉积有利相带控制外，还与地层异常压力的作用密切相关.研究认为陇东地区异常压力的形成机理主要由于成岩过程中粘土矿物脱水作用.粘土矿物大量脱水时间正好与有机质脱羧期相一致，从而在异常压力作用下将生油岩中的大量有机酸及co2带到与之相邻的储集层中，并沿着有利储集相带运移，在酸性水经过的地方形成大量的次生孔隙，为后期油气运聚提供有利通道及宿住空间，从现今的勘探结果来看，通过研究地层异常压力纵横向分布特征，并结合有利相带研究预测次生孔隙育良带是行之有效的方法
On the basis of the study of high resolution sequence stratigraphy , this paper discusses the reservoir petrology ' s diagenesis and secondary pore of the chang 4 + 52 ~ chang 62 pay zones in detail by using the methods of analysis of mercury injection , cast section , popular section , scanning electron microscope , x - ray diffraction and etc . the reservoir rock is mainly composed of feldspar fine sandstone , which is characterized by low compositional maturity and relatively high textural mature 本文在高分辨率层序地层学研究的基础上，通过15口井的常规物性、压汞、铸体分析、薄片鉴定、扫描电镜、 x光衍射、阴极发光、粒度分析等多项测试手段，对坪北油田延长组长4 + 52长62储层岩石学、成岩作用及次生孔隙进行了详细研究。
The great number of pores of reef rocks disappeared due to multi - generational cementation in submarine and taphonomic environments . the pores in reef rocks are mainly secondary and the primary pores are almost filled up . the evolution of pores is wholly controlled by diagenesis , all in a word , the histoty of diagenesis is evolution of pores 礁灰岩中的大量孔隙被海底和埋藏成岩环境中多期胶结物充填而丧失，孔隙类型以次生孔隙为特征，原生孔隙基本被填实，孔隙演化完全受成岩作用的控制，成岩作用的发展史就是孔隙的演化史。
At the same time , structural strike varied from n w - se to ne - sw . with diagenetic evoluation analysis , there are three secondary porosity zones , two of them located in the upper part of the profile whose porosity is small , the other one is located in the lower part whose porosity is up to 10 % - 18 % 根据成岩演化分析可知，研究区内共发育有三个次生孔隙发育带，上部的两个带孔隙度较小，下部次生孔隙带较发育，孔隙度可达10 18 ，其深度介于3500 3700m之间。
The pattern of diagenetic and porosity evolution are established . the primary porosity of the reservoir rocks was 35 % , which was reduced by 21 . 7 % by compaction and pressure solution and 8 . 2 % by cementation . the secondary pores were produced by organic acids " dissolution during organic matter maturing stage , resulting an increase of porosity by 5 % 预测本区砂岩原始孔隙度为35 ，经机械压实和化学压溶作用孔隙度损失了21 . 7 ，后经自生矿物的胶结作用，孔隙度损失了8 . 2 ，当进入有机质成熟阶段，有机酸的溶解作用产生次生孔隙，使孔隙度增加5 ，现今保存的平均孔隙度为10 . 1 。
Yanchang series is a typical low permeability reservoir , and its favourable sandstone reservoir is delta facies . heavy compaction , cementation and heterogeneity exist in it . according to the analysis of the main control factors of forming the secondary pore , it is held that the secondary pore in longdong area is controlled by both favorable facies belt and abnormal formation pressure . it is also held that the formation of the abnormal formation pressure is due to the dewatering of the clay mineral during diagenesis because the dewatering time is identical with the decarboxylation time of organism . organic acid and co2 are driven to adjacent favorable reservoirs under the abnormal formation pressure , and a lot of secondary pore is produced in the runners . from the present exploration result , it is useful to predicting the development of secondary pore to study the distribution of abnormal formation pressure 陕甘宁盆地三叠系延长统是国内外典型的低渗特低渗油田，储集层主要为三角洲砂体，压实作用和胶结作用强烈，储层非均质性非常严重，因此预测次生孔隙发育带是寻找油气聚集带的关键.通过对陕甘宁盆地陇东地区延长统次生孔隙形成的主控因素分析，认为陕甘宁盆地延长统次生孔隙的形成除了受沉积有利相带控制外，还与地层异常压力的作用密切相关.研究认为陇东地区异常压力的形成机理主要由于成岩过程中粘土矿物脱水作用.粘土矿物大量脱水时间正好与有机质脱羧期相一致，从而在异常压力作用下将生油岩中的大量有机酸及co2带到与之相邻的储集层中，并沿着有利储集相带运移，在酸性水经过的地方形成大量的次生孔隙，为后期油气运聚提供有利通道及宿住空间，从现今的勘探结果来看，通过研究地层异常压力纵横向分布特征，并结合有利相带研究预测次生孔隙育良带是行之有效的方法
