珠江口盆地流花油田新近系碳酸盐岩白垩状结构化成因机理探讨  

Genesis of calcification in Neogene carbonate rocks of Liuhua oilfield,Pearl River Mouth Basin

作　　者：侯明才[1,2] 邓敏[2] 冯琳[2] 刘军 吴熙纯[4] 曾驿 周小康 

机构地区：[1]油气藏地质及开发工程国家重点实验室,成都理工大学,成都610059 [2]成都理工大学沉积地质研究院,成都610059 [3]中海石油(中国)有限公司深圳分公司研究院,广州510240 [4]成都理工大学能源学院,成都610059

出　　处：《岩石学报》2014年第3期768-778,共11页Acta Petrologica Sinica

基　　金：高等学校博士学科点专项科研基金(20115122110002);国家科技重大专项子课题(Z2008SLSZ-052)联合资助

摘　　要：珠江口盆地白垩状结构(白垩化)碳酸盐岩是礁滩相沉积体内碳酸盐沉积物在多期白垩化'作用'环境下经成岩作用改造及地下水'漂洗'形成的淡色、疏松、晶间多微孔生物泥晶灰岩。流花油田下中新统珠江组为礁滩相叠加白垩状结构化形成的局部白垩化储层。本文结合流花油田钻井白垩化灰岩分布、显微结构以及碳氧同位素和油田水作用,探讨分析了其成因机制。分析认为白垩化可以分为:缝合线内白垩化、含油层段中等程度白垩化和底水段强白垩化三类,白垩化程度与孔隙度和δ13C呈正相关性。缝合线内白垩为成岩早期大气淡水溶蚀淋滤和晚期压溶作用产物,中等白垩化由成岩早期选择性溶蚀、退变新生变形作用及成岩中-晚期上覆泥岩压实'再造水'非选择性溶蚀作用共同控制,强白垩是前期白垩化成型后受氯化钠型油田水的溶蚀淘洗结果。白垩状结构化经过初期定型,中期强化与孔隙保持,后期加强三个阶段形成。The chalky texture carbonate in the Pearl River Mouth Basin is a kind of white, loose, and porous biomicrite formed in carbonate depositional environments, including reefs and banks. It has experienced diagenesis in a multiphase calcification environment and a ＂rinse＂ by underground water. The Liuhua oilfield reservoir of the Zhujiang Formation is a locally calcified reservoir. It is formed in an environment superimposed by the reef bank where it has experienced the process of calcification. In its discussion on the genesis of calcification, this study focuses on the distribution of calcified horizons in coring wells of the Liuhua oilfield, microscopic texture of chalkified rocks, carbon and stable isotope oxygen compositions, and the chemical action of underground oil-field water. The processes of calcification in different well intervals are divided into three categories： （1） weak calcification in stylolites; （2） moderate calcification of carbonate reservoir rocks along oil-well columns ; and （3） strong calcification in oilfield bottom waters. The degree of calcification is positively correlated with the porosity and 813 C of reservoir rocks. The occurring process of calcification can be divided into three periods ： （ 1 ） the chalky texture in stylolites is formed by dissolution and leaching in the fresh water vadose zone of the early diagenetic stage and by pressure solution in late diagenetic stage; （2） the moderate calcification process is controlled by selective dissolution and degrading neomorphism in the early diagenetic stage and controlled by the non-selective dissolution of the regenerated groundwater from the compaction of overlying argillite strata in the middle and late diagenetic stage ; and （ 3 ） the strong calcification process occurs through the enhancement of formerly calcified rocks through ＂rinsing＂ by the bottom water of the underground oil

关 键 词：白垩状结构碳酸盐岩 新近系 溶蚀作用 新生变形作用 油田水 

分 类 号：P588.245[天文地球—岩石学]