川东北地区飞仙关组鲕滩储层成岩作用——以宣汉-达县及元坝区块为例  

Diagenesis of the Feixianguan oolitic shoal reservoirs in the northeastern Sichuan Basin——examples from Xuanhan-Daxian and Yuanba areas

作　　者：郭彤楼[1] 

机构地区：[1]中国石油化工股份有限公司南方勘探开发分公司,四川成都610041

出　　处：《石油与天然气地质》2010年第5期620-631,共12页Oil & Gas Geology

基　　金：国家油气重大专项(2008CX05005-003)

摘　　要：四川盆地东北部飞仙关组发育台地边缘暴露浅滩相鲕粒白云岩及台地边缘浅滩相鲕粒灰岩两种储层。根据常规岩石薄片观察与阴极发光、扫描电镜、包裹体测温等资料的综合分析,结合印支期以来元坝等地区构造活动强度、期次的研究,开展了鲕滩储层特征及成岩作用研究。结果表明,宣汉-达县地区鲕粒白云岩储层物性明显好于元坝地区鲕粒灰岩。宣汉-达县地区鲕粒白云岩储层在破裂、重结晶及溶蚀等成岩作用方面具强度大、期次多的特征,岩石发生了5期破裂及5期溶蚀,其中第二、第三、第五期裂缝及溶孔对储层形成有利,重结晶作用强烈;元坝地区鲕粒灰岩储层在破裂、重结晶及溶蚀等成岩作用方面具强度小、期次少的特征,岩石发生了3期破裂及3期溶蚀,其中第二期、第三期裂缝及溶孔对储层形成有利,重结晶作用弱。白云岩宏观特征研究表明,鲕粒白云岩是沉积形成的,不是灰岩交代产物。Two types of reservoirs occur in the Feixianguan Formation in northeastern Sichuan Basin, namely oolitic dolomite of exposed shoal facies on platform margins and oolitic limestone of shoal facies on platform mar- gins. Based on an integrated analysis of various data including thin section observation, cathodoluminescence, scanning electron microscope and inclusion thermometry,a study of the characteristics of oolitic shoal reservoirs and their diagenesis is made in combination with the research on the tectonic strength and phases of the Yuanba area since the Indo-Chinese epoch. The results show that the physical properties of oolitic dolomite reservoirs in the Xuanhan-Daxian area are much better than those of oolitic limestone reservoirs in the Yuanba area. The oolitic dolomite reservoirs in the Xuanhan-Daxian area are characterized by greater intensity and multiple phases of diagenesis such as cataclasis,reerystallization and dissolution. The rocks experienced five phases of cataclasis and dissolution, among which the second, third and fifth phases were favorable for reservoir formation, and their recrystallization was strong. In contrast, the oolitic limestone reservoirs in the Yuanba area are featured by weaker strength and less phases of diagenesis such as cataclasis, recrystallization and dissolution. The rocks experienced three phases of cataclasis and dissolution,among which the second and third phases were favorable for reservoir development, and their recrysta]lization was weak. The macro-characteristics of dolomites show that the genesis of the oolitic dolomite is deposition rather than limestone metasomatism.

关 键 词：鲕粒白云岩 鲕粒灰岩 破裂作用 重结晶作用 溶蚀作用 白云石化作用 飞仙关组 川东北地区 

分 类 号：TE122.2[石油与天然气工程—油气勘探]